Aquaponics Rocks

[Guest]

That's a hot tip NT and I thank you very much. I think it's possible to plant the tank I only have goldies and two new comets they're not big on 'fresh veg' preferring their carbs half rotten.

Question is, how much nitrogen do these plants draw.

I asked Shipperke about it as he's always got wisdom to spare and 160ppm is probably ok for goldies as they're so tough but I'd like 100 ppm so as to have a system that will support more than just the hardiest fish. 160 ppm MAY cause health problems over long term with dantier species.

So you're a bio-bucket guy, excellent, if I didn't discover this I'd be bio all the way!

 

[RM - aquagrower]

congrads on getting some testing supplys. the way i see it, running without them would be like driving down a dark road without the headlights on. the fact that you've been running successfully for 2+ years without "the headlights on" speaks volumes about your growing ability. you da man!

i don't think that partial water changes are such a bad thing. actually a few weeks back i started dumping 5 gal about once a week from the grow system. the thinking was that the plants can't be using EVERYTHING that the fish provide.

speaking of what the fish provide, now correct me if i'm wrong as i'm far from a fish expert, fish piss in the water, as well as shit in it. now with the fish piss being mostly amonia, that gets turned into nitrites, that turn into nitrates, maybe it's the fishes piss that's providing our plants with the N they need, and the solids provide other things that the plants need. regulated by diet of course.

 

[Guest]

THSeek-
First, let me formally introduce myself. I started growing in hurtback's bio-buckets, and quickly became interested in aquaponics as a natural means of organic hydro. I eventually researched myself out of aquaponics though, for a number of reasons... which you and others seem to show somewhat unfounded.

1) I grow using DWC, and was concerned about a lack of adequate bio-material.
2) I was concerned about mono-cropping in aquaponics with a crop that needs high levels of P and K
3) Metanaturals accomplishes my goal of organic hydro without the fish and with predictable results.

I was thoroughly bitten by the "aquaponics bug" however, and have experimented with a 75 gallon planted aquarium with rainbowfish and swordtails growing lettuce via NFT channels. I just finished my next "stage", a 700 gallon in-ground fish tank with 60 cubic feet of gravel in 3 20 square foot grow beds fed via ebb&flow. (Actually, one bed is finished, the other two will be added as fish mature and new generations are added) I am growing Oreochromus Mozambique, a species of tilapia, and several different types of vegetables including tomatoes, basil, lettuce, spinach, cucumbers, squash, peppers... All of this will be enclosed in a greenhouse, but right now it is open air. I have done far too much research on the subject, and probably have annoyed quite a few people with questions (ask Shipperke), but I feel pretty good about the overall concept and I haven't had any massive fish die offs in a long time now...

I'm glad to see more people trying it on our favorite herb, but for my circumstances, it just isn't worth it. However, if you wish, I would love to share my experiences or advice with you. For starters, may I suggest this article written by Diana Walstad (the unofficial queen of planted aquariums, if you buy any aquarium book, it should be hers). It can be found here: http://www.aquabotanic.com/plants_and_biological_filtration.htm

Notably, she describes how most aquarium plants prefer ammonium to nitrate, while the opposite is true for most terrestrial plants. Ultimately, this means that if you choose to incorporate aquatic plants as nitrogen sinks for your mj grow, this may reduce your need for bio-material for the nitrification process, as aquatic plants will use nitrogen in its ammonium state.

As far as your question regarding the amount of anacharis (Elodea densa) needed, unfortunately, I have no practical experience to guide you except... use as much as possible. Obviously there are limits to what your tank would support, and I am not aware of your particular fish bio-load, but a HEAVILY planted aquarium can be supported by relatively small fish loads. Anacharis is cheap, use more than you think you may need, and adjust accordingly after doing consistent nitrate and ammonium tests.

You should be testing for ammonium anyway, for your fishes health. I do weekly tests of GH, KH, pH, NH3/4, NO2, NO3, and Ca.

By the way, if you test for Ca and GH, you can determine Mg levels using a calculator found here: http://www.plantedtank.net/forums/planted-tank-faq/16040-calculator-determining-magnesium-gh.html
It works because GH is a measure of Ca and Mg, obviously if you know one, you can determine the other.

Good luck, and please let me know if my advice is wanted or unnecessary, I have a tendency to be long winded...

RM - I am no expert, but I believe your reasoning regarding "fish piss" is correct. I have found that most commercial aquaponics farms that grow greens like lettuce filter solid wastes, while most that grow higher vegetables keep solid wastes in system to account for more than just high nitrogen nutrient solution. Partial water changes of course reduce all nutrient levels, not just N, therefor it isn't desired unless you don't mind supplementing with non-nitrogen nutrients. Depending on the quality of your feed, partial water changes may be necessary to reduce Na levels, that are unfortunately high in most "aquarium" fish feeds.

And now, a question, if you don't mind. My water is extremely odd. Up until now, I have always used RO water for my grows and aquariums, but the new outside legal grow requires massive amounts of water and I have resorted to tap water. My water from the tap (after resting for 24 hours) has 535 ppm (@.5)!, pH of 8.0, and GH of roughly 18ppm, but a KH of nearly 500ppm. This means I have a unique situation of having MASSIVE amounts of carbonates with virtually no Mg or Ca. Am I correct in assuming that the likely culprit is Na? And if so, why isn't contributing to TDS? Does anyone have any advice for reducing KH (short of RO water or boiling water, neither of which are very feasible in 700 gallons), or am I just screwed? Life is always interesting.

 

[Guest]

Nt.

Be as long winded as you like I love all this Aqua stuff. Halfway through a blunt so if I digress a bit myself...

Your tap water sounds horrendous!

I would check bigtokes thread on water quality stickied in hydro. it's two pages of just bigtoke on bio and water now and well worth reading through, plus the info on KH is spread throughout. It's all bloody rocket science to me now but I've grasped several other new 'languages' and hope to join your century shortly.

Pre-cycle your water definately, but how?!

Got another test given to me today. It's called Freshwater Hardness test, is an aquarium product, 3 bottles (sodium hydroxide, calmagite solution & EDTA color indicator).

My solution, or reservoir - tank! shall we call it, is 580ppm.
My tap water (pH 7.0) is 90-100 ppm.
My pH is a rock steady 6.2-6.3 each day (only 3 days tested) 1/2 way into the light cycle regardless of adding water back or letting it go down a bit. I'm happy it's rock steady but I'd like to get it higher by pre cycling the top up water.

I want the right pH up product safe for fish and plants. Am I looking for Potassium Bicarbonate? Grow nute products wont cut it, we get very few brands here and I too am expanding to veg outdoors.

Way I see things with my system now is that my fish are starting to overgrow the system as I can't increase foliage (no space) other than using Aquatic plants. This is a good solution however it detracts from system efficiency ie: turning poos to pennies. At first I had deficiencies with less foliage and as the fish grew the grow grew still minor deficiencies I supplemented and expanded to DWC with supplement schedule... now I barely touch the supplements (total 5ml catalyst 5 ml microblast in last month) and with massive fish, massive plants, I may need to hurry up and get that pond in outdoors to let the big Orando run free with a couple of his bitches. Told you I'd digress hehe.

I really am trying to understand what tests are best first and what information is the most relevant however it hasn't 'clicked' yet. I see a light then it dims.

TDS. WTF? lol.

RM - Water changes will work yes. It was good running zero waste so long though, removing a fish would be more the ideal I'm looking for, but will it work, how do I get my fish to sit on a scale so I can work this shit out and revise my formula?

I wasn't driving with no lights, I had a horse!

 

[RM - aquagrower]

weekly update at 8 weeks








gotta go to work. see ya'll later.

 

[Guest]

THSeek -
From your description, I believe you have a GH test kit... if I'm not mistaken, the test solution should change from red to blue as you titrate in EDTA. (The calmagite is actually the color indicator, EDTA just binds to Ca and Mg and precipitates out, eventually substituting red Ca/Mg + calmagite compound for the blue calmagite. This is good, because if your pH is stable, then KH is most likely in an acceptable range anyway.

For sources of potassium bicarbonate, try nursery stores (it's used as a fungicide), drug stores (may be more expensive), home brew supply stores, or online. Be aware that potassium bicarbonate will increase your KH, which will increase your pH buffering capacity. This may or may not be what you intend. If not, try looking at potassium hydroxide.

For bare minimum testing, I would suggest NH3/4, NO3, and pH. GH, KH, NO2, and Ca I would classify as useful but not absolutely necessary. If problems arise, you could purchase test kits for Fe, P, K, or Na, but otherwise I don't think the cost is justified.

 

[BakedBeans]

NT, how many commercial aquaponics operations are you aware of? Are these in the states or elsewhere? Just curious, I don't know what country you live in, but I'm assuming the US.


I wanted to get some real world info and so I was eating at a local restaraunt and happened to talk to the owner. I asked him how much he paid for his Tilapia but he didn't know. He did go back and pull an invoice and look though.

Info from Sysco (super mega-huge food distributor)
$2.36/lb
10 pounds per case
20 cases per week on average

He's opening up two more locations within 16 months and told me that it would be worth it to get *certified* organic produce and locally harvested fish. He said a lot of organic farmers come to him wanting to sell veggies, but due to health code restrictions, he has to get stuff from certified farms. I feel this may be a slight obstacle seeing as how aquaponics is very fringe and I don't think even hydroponic production has been certified Organic yet (even when running 100% organically).

Might not be as hard with Aqua though, considering you're not adding many chemicals once everything gets going.

I started doing math and the numbers were staggering. That would be a lot of fish raising just to support locally in a good mid-sized city. The good thing would be with aqua, the veggies will probably even out the expenses. I'm assuming that the fish will be more costly to raise than the plants, but I need to do more figuring. Lots of hidden costs in there, but thankfully, they're almost all startup costs. I think once a properly balanced system is up and running, it would pay for itself very quickly, as long as everything was thought out well enough.

I'm just trying to decide what kind of fish I want in my tank. I think I'm going to go 50-75 gallons to start. I'll be able to pick one up for a few hundred bucks, which isn't a big deal. It's going to be all of the other stuff.


Anyone have any idea how many fish can be crammed into a tank, given ideal conditions and leaning more towards commercial production rather than as 'pets'?

 

[muddy waters]

high all:

anyone who hasn't gone through the aquaponics-l archives:

http://www.i55mall.com/aquaponics/

GO NOW!
(you're welcome)

next week i'll begin with some details and photos of my small scale indoor aqua project and slightly larger balcony "legal" one.

until then...

 

[Guest]

BB - Yes, I'm in the US. There are several large operations nationwide, unfortunately none near me. A large percentage of international aquaponics operations are run by missionary type organizations due to aquaponics relatively low requirements for fresh water and land. University of the Virgin Islands has two week long aquaponics courses held each summer, they are on the forefront for educational institutions. S&S Aqua Farms is also one of the leaders in gravel bed aquaponics. They run the mailing list that muddy waters posted the archive for. It's definately worth subscribing to that list.

I know of a few operators that are certified organic for veggies only, evidently it is cost prohibitive to formulate organic fish feed therefor providing organic fish. Most tend to market as "natural" or "pesticide free" as there aren't any government regulations then, but of course the price premium goes down.

From what I've found, the vegetable production is where you actually make money, as the aquaculture industry is traditionaly very price elastic, and there is little margin for profit. The key is to find a niche and exploit it. Usually that means off-season tomatoes, fresh herbs, and packaged salad blends. Don't forget that one of the key infrastructure requirements (if one isn't available nearby) would be a cold house to rapidly cool produce. This would be a major investment, and operating expenses would be high, probably higher than the greenhouse itself. Economy of scale plays in here though, so the larger your operation is, the cheaper per unit the cooling expenses are. I am a long way from considering commercial production, however, I won't rule it out in five or ten years. I still have much to learn.

At MAXIMUM stocking levels, you could get about 30 lbs of fish in a 75 gallon tank BUT, I don't think a 75 gallon is anywhere near large enough for any more than 10 pounds of full-grown tilapia size fish realistically. I don't know your plans, but THSeek has found 1 pound of fish per 4 square feet of grow to be a decent guide. One commercial greenhouse I have visited gets about 2.5 square feet per pound. Differences in crop grown and livestock make these figures very flexible. I would not recommend food fish in any tank less than 2 feet deep and 2 feet wide, which would rule out a standard 75 gallon tank. If you are dead set on it, look at using a livestock water tank or something a bit larger. At one time I had considered building my own large tank (400-500 gallon) out of plywood, I can help you out there if you like. Otherwise, consider stocking a popular aquarium species that you can sell back to your LFS for credit or cash.

Here is the thread I started last year when I was considering aquaponics for mj production, unfortunately, the majority of my posts were made at CW and are now lost... http://www.icmag.com/ic/showthread.php?t=11420 . Reading through it now, most of it still applies, but some of the theoretical figures are off.

 

[Guest]

RM - that space has no space left! Nice one, when's harvest? I really should photo this next plant coming through it's a beauty. Still got powdery mildew where it started but it's ceased spreading. That crap Aquaticus organic spray is a most excellent leaf polish, now I know how they get those photo finish shots...

NT - I'm giving stocking rates for MJ. With lettuce or other leafy crops I'm sure a lb of fish would feed twice the foliage cover or more. MJ figures could be a little heavier on the fish but not much judging from the 580 ppm in solution I have now. However my figures are not 3 lbs of fish to 12 sq ft anymore, 4 1/2 lbs and growing of fish now. I think a really good ratio for heavy fruiting crops would be 1 lb fish to 3 sq ft foliage cover. This would need to be in a well established system, it certainly shows good results and no need to supplement, but may be too rich for many fish species. Still learning.

My original formula will give great MJ results, tweak at owners risk.

Cold storage for produce - F*** that! Too much for anything but a LARGE operation. I'll have my veg in the markets within an hour of being cut, let them cold store it. Never cold stored anything from a multi cropping 10 acre market garden - to the markets we go!

Cold store for fish yes, or at least cold transport to local processors.

 

[RM - aquagrower]

hey guys,
looks like the NL girls are getting close to a window of harvest. i'm hoping that she re-pops again tho. buds look a bit small. lady ice looks at least 2 weeks away, but i think that she'll easily produce twice as much as each NL.

 

[Guest]

I had strain specific results, perhaps you are seeing the same. Time variants to the norm too ie: Superskunk ready in same time as other hydro growers (maybe day or two later) more sativa in the mix seems to like an extra week or even more according to the strain. This last bit can make a lot of difference to weight. Your loupe will guide you well. I have just 'picked a bit till it kicked' then harvested. Loupe for this next plant though.



It might be damaged by powdery mildew and thrip but it's kicking ass regardless. The plant next to it went in with the new ventilation and has no mildew visible and very little thrip damage since giving it a leaf polish.

I mentioned the polish, check it out!



The JH phenotype I have has some funky looking buds but only one photo I took of budshots was salvageable (legible even). They grow looking like pineapples a bit on top then from this point (7 wks-ish) they spread in all directions. Lets hope they stay tight this time with lots more air and resultant lower temps.



And here's some fish porn for ya. My organic answer to iron. The parsley will start to look like it's rotten over 5-7 days then the fish hit it when it's 'palatable' to them.



I caught a goldfish grazing the biofilm yesterday, interesting, does bio-film protect itself at a certain level by exuding tasty smells or something similar in intent so it is grazed allowing for population growth rather than a population crash at max capacity? Hehehe who's toasted again.

 

[Guest]

Oh yeah - lowered nitrate from 160 ppm to somewhere between 100 and 120. this was achieved over 4 days adding a total water volume of 36 litres with 50% of that being changed out and 50% being drunk by the system.

And here's some psychedelic fish porn.

 

[BakedBeans]

holy crap, I'm stoned as I type this and that picture freaked me out. I was reading along and not skimming the pictures.

I'm not sure now if I want to get the fish setup and working and then move to a growing situation, or try for aqua from the start. It's my first grow, and while I'm researching the crap out of everything, and am pretty confident in my skills (I'm a computer engineer after-all), I'm just not sure if I want to deal with two whole subjects at once. I've been thinking Bio-buckets for the grow, and still getting a 75gal tank for fish. Oh, and I'm not going to raise Tilapia in the house LOL. More like the fish you guys have, just pets.

Anyway, I don't know what I'm going to do yet, but something... Soon.

 

[Guest]

BB- If I may make a suggestion... If you have prior experience with planted aquariums, I'd say go for it, start off with aquaponics. If not, then you might want to consider getting a round or two under your belt with just the mj alone. I like bio-buckets, but the biggest challenges I had when starting was adequate nutrient solution circulation and temp control. I had minor issues with root rot my first grow, manifesting itself about halfway through flower. My suggestion is to plan for water change of at least 15 times per hour (6 five gallon buckets is 30 gallons, multiply by 15 equals 450 gph pump), after loss through lines and connections, you should still have more than 10 exchanges an hour. And make sure you can keep nutrient solution temps under 72F, I use evaporative cooling for this. Also, despite what Bigtoke claims, I find the Lucas formula in RO to be excellent. Thats 0-8-16 with GH Flora or 10ml 3-3-3, 10ml 1-5-5, and 1/4 tsp MgSO4 for Metanaturals.

Knowing what I know now though, especially if you plan on going aqua, I would suggest looking at a medium based grow like E&F for a number of reasons (not that DWC won't work, just that E&F may be easier):
1) Nutrient solution temperature is no longer an issue.
2) Bio-material is in the root zone.
3) No need to pre filter solid waste from the effluent.

For what it's worth, I grow in bio-buckets because thats what a started with, but I use metanaturals for mj, not aqua. If I were using aqua, I would retrofit to E&F.

I'm glad to hear you are ruling out food fish for a 75 gallon aquarium. If you are still looking for a main aquarium species, check out rainbowfish or angelfish, as they aren't terribly hard to keep and their offspring is actually worth something you are lucky enough for them to start breeding. I strongly suggest that you get at least some plants up and running first before adding fish to the system. This will allow nitrifying bacteria to colonize the bio-material and will allow fish waste reduction immediately after fish introduction. If you start both at the same time, start small on the fish side, and be prepared to monitor NH3/4, and NO2 closely, and do water changes if any more than one or two ppm shows up.

Plenty of sites on the web about rainbows, but here is one that has a brief description of all the different genus: http://www.wetwebmedia.com/FWSubWebIndex/rainbows.htm . I'm partial to Melanotaenia boesemani. Regardless of what species you choose, if you start fish and plants at the same time, you might consider starting off with a cheap fish like goldfish, as you may experience a few deaths in the beginning while waiting for equilibrium of beneficial bacteria to fish waste production. I was once a mass-murderer of fish because I failed to adequately prepare for larger populations. I am also fond of Malaysian trumpet snails, as they are excellent substrate aerators and help to predigest solid waste and leftover food prior to your bio-material. Be careful though, as I have heard that snails may harbor nasties that cause diseases in fish. As with anything else aquarium related, only buy livestock from a clean, reputable source, and consider using some feeder fish in a quarantine tank with your snails for a month or so to make sure that the snails aren't infected prior to introduction into your main tank. If you ever have to dose meds in your tank, make sure that it is safe for planted tanks, or disconnect your tank from the aqua system during medication if it isn't.

Please excuse my blabbering, I hope it was at least coherent. Good luck and keep us updated please.

 

[RM - aquagrower]

took a sample bud the other day and oh my! weed is strong! checked the trichs this morning and found all to be cloudy, only saw 2 amber. saya in the strainguide that both NL and ice go for 55 - 65 days and we're at day 58 now.

BB,
i know that ya said you've got little to no experience w/ fish, have ya grown mj before? if not, have ya got your grow space designed/built yet? if not, do you know where you'll be putting it? do you want your tank to be an "aesthetically pleasing show tank" placed out in the open, or are you going for a more "utilitarian tank"?

first thing i would do is get the tank drilled, if it hasn't been done already. cost about $100 and really opens up your design possabilities. the holes can always be plugged until needed.

if this will be your first grow, i suggest that ya go soil on the first one. that way you can concentrate on providing the plants with a good "above ground" envronment before tackling the "below ground" stuff. and ya should come out of it with a good mother plant.

it'll take about 3-4 months to get thru the soil grow, during which time ya can get the tank set up and the system built. i would set the tank up with ugfs and appropriately sized hobs. that way, when the time comes to hook the tank to the system, it is simply a matter of hooking up a couple of hoses and no longer using charcoal in the hobs.

personally i like dwc for indoor applications, but i don't want to get into a debate about it. that choice is yours. i can picture a nice show tank on a nice stand placed against a wall with the grow room on the other side, maybe in a closet?

 

[Guest]

NT - The ebb and flow systems are inefficient compared to continuous flow for Aquaponics. Why? I know not. But I do know a scientist spent the best part of 3 years in Aquaponic studies and had 20% better gains with continuous flow as opposed to ebb and flow.

This was not DWC, it was merely watered medium beds, with continuous flow.

I went DWC as folk were perpetuating all sorts of bullshit about the subject. - Can't be done organically, need air in every bucket, have to change out system all the time etc etc.

Partly I did this because I'm a smartass who doesn't understand the word can't, I also knew, from studying hurtback obsessively, it would work.

For a heavier fruiting crop (MJ) massive root zones make all the difference in your crops potential as you'd know. I doubt I could pull an oz plus per sq ft using shallow beds but in DWC it's now a given.

 

[muddy waters]

hello peeps... i just wanted to toss a line out there and see if i get any bites... thanks in advance

does anyone here have any experience with aquaponic drip systems?

i'll have a future post with photos and diagrams detailing what i am doing but i am still in the design phase of my aquaponic rig, which is basically a 30 liter tub, with a 650l/h powerhead, shooting water up a few centimeters to a 13.5 liter tub placed directly on top of the lower 'aquarium' tub, filled with small diameter expanded clay. this upper tub is heavily perforated, so that watr drips down to the lower tub and roots may leave the media and enter the aquarium. i plan to grow either 4 or 6 plants in a SOG, 12-12 from seed arrangement (buds on a stick), with a staggered harvest meant to balance nutrient uptake among the plants.

having explained the basic setup, what i am now trying to determine is the specific mechanism to use for dripping the tank water over the bio-filter media in the upper tub to ensure maximum dispersion and efficient bio-filtration. my best idea thus far is to construct with 1/2" PVC a rectangle which will sit atop the expanded clay, full of holes on the underside, with a larger hole somewhere on top to insert the pump line.

i'm concerned about two things--keeping this device level, to ensure even distribution over the bio-filter--and making the drip holes a good diameter so that they do not clog too frequently yet not too large to regulate water flow. i'm thinking something like 3mm.

i'm also always in doubt as to size of the bio-filter. I have researched this thoroughly and seen a wide range of recommendations. One book I have suggests that the ratio of tank volume to total bio-filter volume should be something like 1:4.4, which would mean one truly gigantic bio-filter. if anyone could chime in with their ratio and their preferred media (i know lava rock is popular but unfortunately i don't have access to it), i'd be grateful. as the entire volume of water in this setup can't surpass 30 liters, i expect to get adequate aeration from the 650l/h pump and the constant trickling over an open bio-filter. the bottom tub or tank, itself, however, is almost entirely enclosed by the upper tub--would it be necessary to add a venturi line to the pump to oxygenate the water before dropping it over the bio-filter?

looking forward to getting this thing up and running... happy grows to all my aquaponic bros!

 

[Guest]

MW - I have no experience with drip systems, so unfortunately I can't help you there. I have built my own trickle filter though, and the key to efficient use is dispersal of effluent over the entire drip field. Otherwise, the effluent will drain through narrow zones in the medium, and although you may have a huge amount of bio-material, very little of it is actually being used. Beneficial bacteria can not survive being completely dry.

As for bio-material ratio to water volume, even under very high stocking rates, 1 gallon water to 4.4 gallons bio-material sounds quite high. S&S Aquafarms uses a ratio of 1:2 (they use gravel beds), and that's with one pound of fish per two gallons. Since you won't be using anywhere near that high of a stocking rate (I hope), instead of using (gallons of water) : (gallons of bio), I suggest converting it to (pounds of fish) : (gallons of bio). Using S&S figures, this works out to 0.5:2, or 1:4. This will probably end up being more than you need, but more is far better than less.

It should be noted that THSeek reports success with half of this value (according to the figures on page one), so obviously this isn't a hard and fast rule. Ultimately, you need the bio-material to do to things: 1)Act as a home to nitrifying bacteria to reduce NH3 to NO3, and 2)Mechanically filter solid waste from the effluent and hold it until bacteria can break it down into water soluble nutrients. If both of these are accomplished, than your bio-filter is at least adequate.

 

[muddy waters]

NT, appreciate getting your thoughts on this.

with regard to dispersing the effluent over the entire bio-filter to avoid dry spots: is the plant able to regulate humidity within its rhizosphere to any extent? that is, will a properly hydrated plant (say, with roots going into the res) be able to allot some of its moisture to parts of the rhizosphere that are not in the direct path of water, in order to facilitate root health and beneficial bacterial growth? i know that the plant exudes sugars through the roots but i don't nderstand that much about the water transportation system in plants.

anyway my thought was that the presence of root mass in the bio filter might aid in the distribution of the water, avoiding the narrow channels you were talking about.

the drip thing has a very simple premise but it's trickier than it seems, i'm seeing now... i guess that's one of the major advantages of the S&S type system--the flood stage immerses ALL of the bio-filter's superficial area.i admit though i'm less comfortable with the dynamics and timing involved in that sort of system, having little experience with valves and little faith in cheap timers

peace,
M