Dropping Science - SpicySativa's Microbe Wrangling Experiments

What's up everyone?

So... I wanted to start up a thread to document my various microbe related experiments.

I built myself a compost tea brewer roughly following MicrobeMan's recommendations on his website (Microbeorganics.com). Here's what I've got:

~5-gal Homer Bucket

~EcoPlus Air 1 Commercial diaphragm pump

~Home-built 3/4" PVC diffuser in an "X" design with two 1/16" holes drilled in each "leg" of the "X".

~Adjustable aquarium heater

~pH meter (kindof a crappy one, but reasonably accurate)

~Hach Dissolved Oxygen Meter (very accurate)

~Various worm castings, ammendments, etc.

~High hopes of greatness (which science does not always allow)

I assembled my brewer and gathered the following ingredients for a 4.5-gallon batch of AACT.

~1.5 cup of worm castings from the local worm farm (fed composted horse manure, coffee grounds, and "various food waste")

~2 TBSP kelp meal

~1 TBSP soft rock phosphate

~4 TBSP Eco-Hydro Fish Hydrolysate

~2 TBSP Hi-Brix molasses (Earth Juice brand)

The compost, kelp meal, and rock phosphate went into a 1-gal paint strainer bag suspended in the brew, the rest was mixed into the water. Here's how it went:

6:30 PM - Fire up the pump, begin brewing
pH = 4.3
DO = 9.92 mg/L
Temp = 15.1 *C (kinda cold...)

8:50 PM - pH = 4.9
DO = 8.84 mg/L
Temp = 21.4 *C (the heater did it's thing)

7:15 AM - pH = 5.6
DO = 8.42 mg/L
TEMP = 21.0 *C

6:30 PM - pH = 6.2
DO = 1.10 mg/L (BAD BAD BAD BAD BAD!!!)
Temp = 21.6 *C

I double and triple checked that dissolved oxygen reading, but it was the sad sad truth... That's the thing about science experiments, you don't always discover what you want to.

So... I'm back to the drawing board, and hopefully you guys can help me out. I need to figure out how to coax enough dissolved oxygen from this EcoPlus pump to keep my brew AEROBIC!

I suspect my problem might be the large size of the bubbles this thing produces. Sure it's cranking a lot more air than my old fish tank aerator and air stones, but I bet it had LESS bubble surface area than my old setup...

So what'ya think?

Or maybe I used too much food for my brewing temperature?

Help me brainstorm here...

Only thing you need no is a microscope.... one day I will get one, maybe after this grow.. GL with the thread

I just ordered caps bennies.

I should have researched a bit further and done what you are doing.

Good luck to you, hope it works out.

I have lots of pictures to add, but for now, it's State of the Union time...

W89 said:

Only thing you need no is a microscope.... one day I will get one, maybe after this grow.. GL with the thread

Click to expand...

It's true... I do need a microscope, but for now I can learn a lot jus by monitoring dissolved oxygen levels. This first test was a real eye opener for me. I've brewed many compost teas prior to using the DO meter and I guanartee some of them have been anaerobic. Regardless, the plants always seem to LOVE their tea. That's exactly why I'm hear trying to perfect them. It's the tangible results I've already seen as a novice brewer with no microscope...

I use the EcoPlus 5 for my 5 gallon brews......

the airpump I use is 40lpm what sort of volume of water would that be sufficient at keeping the right DO reading? that is following MM guidlines for CT... just EWC and molasses? I have started making my teas a lot simpler

The pump I have is about 40 lpm (38 I think). I suspect that isn't the weak link here...

if it was my brew, i'd have only added 1 cup ewc and maybe a third cup molasses (not earth juice brand). keep most of the other stuff for your soil mix.

Why SRP...in an ACT.
Also....kelp has been shown to slow bacterial development....not that that's a horrible thing if you understand it.

What schwagg said...he works with CTguy.

I used the MM recipe last CT I mate, before I used to add un measured amounts of things just cups or spoons in no peticular ratio, now following MM guidelines I should be as close to a good CT without actually looking at it under a scope as his method is tried and tested, I am going to stick with what whats been proved to work.. Without a microscope your really just shooting in the dark so why risk making a void tea when we have the proven recipe already there

Gascanastan said:

Why SRP...in an ACT.
Also....kelp has been shown to slow bacterial development....not that that's a horrible thing if you understand it.

What schwagg said...he works with CTguy.

Click to expand...

SRP supposedly gives the fungi something to anchor to in the tea. Figured I'd give it a shot. This was just one trial out of many to come. Next try will be a simple mix of just worm castings and molasses (my "baseline" recipe).

SpicySativa said:

I suspect my problem might be the large size of the bubbles this thing produces. Sure it's cranking a lot more air than my old fish tank aerator and air stones, but I bet it had LESS bubble surface area than my old setup...

So what'ya think?

Or maybe I used too much food for my brewing temperature?

Help me brainstorm here...

Click to expand...

Based on my aquatic knowledge I will say food, not bubbles/aeration. Typically air bubbles, what are moving through the water column, have insufficient surface area to really have much affect on the CO2/O2 gas exchange. That occurs at the water's surface, so turbulence and turnover is what we're after to achieve highest DO levels. If the bucket has mad crazy turbulence, then I'll suggest that something has consumed the O2 very quickly. If you can, do a side-by-side with plain water and test your DO levels.

Venturis have been shown to increase DO levels. I have no idea how you would incorporate a venturi into the design as I'm envisioning it, though.

Photo dump from the first (documented) brew....

SeaMaiden said:

Based on my aquatic knowledge I will say food, not bubbles/aeration. Typically air bubbles, what are moving through the water column, have insufficient surface area to really have much affect on the CO2/O2 gas exchange. That occurs at the water's surface, so turbulence and turnover is what we're after to achieve highest DO levels. If the bucket has mad crazy turbulence, then I'll suggest that something has consumed the O2 very quickly. If you can, do a side-by-side with plain water and test your DO levels.

Venturis have been shown to increase DO levels. I have no idea how you would incorporate a venturi into the design as I'm envisioning it, though.

Click to expand...

My working theory is that the higher temps and ample food supply caused a bacterial "bloom" that the air pump couldn't keep up with. I did a quick-n-dirty brew the other day before I bought the heater. Temps stayed around 60*F, oxygen levels remained above 8.4 mg/L (if I recall correctly), and the plants loved it. I wrote a little about that trial in a thread titled something like "Compost tea going acidic" or soomething like that in the "Nutrients" forum. Check that one out if you're interested.

I think if I'm using a higher temperature, I might need to use less food and/or less compost to slow the growth down a little.

Gotta spread some rep before hitting you again, but I agree strongly with your working theory sans scoping. I think I posted in that thread, too.

I think you're on to something with the bubble size theory. And a large bacterial bloom could be using the O2 so fast that your metered DO would be inconclusive, as you guessed. For your experiments, you're probably better off with a very basic recipe. Keep experimenting and posting the results. Good luck. -granger

I think I see a DIY vortex style brewer in my future... The only thing holding me back is the thought of cleaning all the air lift tubes, etc, etc... Either way, I've already built the bubble bucket, so I'll continue to test and tweak it.

I think my next step will be removing the little hose barb fitting from my EcoPlus pump. As MicrobeMan said, the hole on that fitting is TINY, and clearly restricts airflow.

Well, I bought myself an EcoPlus Commercial Air 5 yesterday. I haven't really had a chance to properly try it out yet, but I did hook it up to my PVC "X" diffuser for a minute. I didn't have a bucket full of water to dunk it in, but I can already tell I'm gonna like this pump. I could feel a strong jet of air blasting from each hole, whereas before it was barely perceptible until the thing was under water.

I'll test out my "bubble bucket" with the new pump while I gather the parts for my vortex brewer build. Looks like I've got my work/fun cut out for me.

Stay tuned...

Still haven't been able to run a proper tea brew with the new EcoPlus Air 5, but I did fire it up in a bucket of plain water with my PVC "X" diffuser this morning... All I can say is this thing blows some SERIOUS bubbles! I started it up with about 4.5 gallons of tap water in a 5-gal bucket just to see how it bubbled. I plugged in the pump, and within about 15 minutes it had splattered a full gallon of water out of the bucket. This pump is NOT fucking around...

Looks like I'll need to fix up a lid if I'm going to run this pump in a bubble bucket style brewer. Good news is I don't see this having ANY issues with extraction, mixing or aeration.