DWC DO

[saldiado]

I just finished putting together a 20 gallon rubbermaid DWC. I may have cut the corners a little too much on this one, and was hoping to get advice from some of the pros i have observed on here. My main question is how many air stones would be ideal for a 20 gallon tub? at the moment I have an aqua culture dual pump( 10$ at walmart supposedly for 20-60 gallons) and two air stones one 14 inch, and one 10 inch. it seems to be mixing things around pretty well. I tossed 2 5 week old plants into it, and the roots after a couple days started turning a little brown, and i was thinkin it was the pump, and stones, but then i noticed a small light leak where the tubes from air pump were going in, so im pretty sure this was due to light leak, but still would like to know if everything else sounds good?. Sorry to ramble, school and writing were never my strong points...

 

[Haps]

You are OK on DO, I use those air pumps, they last about three years and do fine. Check the stone function between blooms those will last 1-3 grows, no longer, I do not use air stones, but I did for years. Check water temp, the brown is probably from nutes, not the light.
H

 

[saldiado]

Thanks for the quick reply. its good to know you really can get the pumps for that cheap. You said you dont use air stones.? im hopin your right about it being from the nutes, the plants are definitely still showing healthy new growth everyday, and the temps have been steady in late 60's early 70's in res. i will keep a close eye on it. thanks again

 

[oldschoolfarmer]

In the past I used a 20 gallon tub with 2 air stones, this was during summer and root rot set in quickly (I believe it was due to lack of oxygenation). I used the wal mart pumps, and while they do last a decent time; they don't necessarily fill the tub with bubbles.

This go round I'm using 4 stones per tub with a high-flow pump; so far no issues with rot but then again it is winter time

One thing I've learned is roots love bubbles. As for rotting issues, as long as the rez temp stays under 70 it shouldn't be a problem. I can't afford a chiller so I try to get as much oxygen as possible.

good luck!

 

[saldiado]

SO maybe a couple more airstones in there? is keeping a frozen glass bottle in the res a cheap alternative to keepin it cool? my temps have been steadily around 70, 73 tops. would these wal mart pumps work well for a 5 gallon bucket? thanks for the help.

 

[oldschoolfarmer]

the frozen glass bottle will help, but trust me once summer hits it will get old realll quick. the walmart pumps work fine for a 5 gal or even 30 gal tub, just make sure you have enough of them (or keep the water temp under 70F).

 

[FreezerBoy]

While the ice bottle boogie gets tiring, it does work. I've got a Whisper pump rated at 60 gal in my 18 gal tub. However, after allowing for net pot and air gap it only holds 12 gal. Having tried various bars, discs, ceramics etc, I've found the the common 48¢ stone most effective. Don't expect roots to stay pearly white. Some staining is inevitable. The more you avoid organics and additives, the less chance of rot you'll have.

 

[saldiado]

what distance would you recomend for air gap?

 

[Arlen]

You know, you could always buy a small mag-drive pump, like a danner 350, not expensive at all, and run it to loop, dont put it in the res but tap the supply on the bottom and elevate the return, to fall back into the top. This will draw in air as the water falls and aerate your water very nicely at the same time.

 

[FreezerBoy]

You know, you could always buy a small mag-drive pump, like a danner 350, not expensive at all, and run it to loop, dont put it in the res but tap the supply on the bottom and elevate the return, to fall back into the top. This will draw in air as the water falls and aerate your water very nicely at the same time.

Waterfalls are the best method of aeration but, water pumps heat the water leading to root rot and other problems. If you can do this AND keep temps under 70º, great but, you may need a chiller

what distance would you recomend for air gap?

Some don't, keeping the bottom of the pot submerged at all times. I start with a 1" gap (once roots are long enough to clear it.) Conveniently, my tub holds about 1 gal per inch. I let water drop 4 gallons before topping so the full swing is between 1-5 inches.

 

[mpd]

Sounds like something is amiss. SM-90 cures most root problems and really helps promote strong root growth. I also believe in surgically clean equipment and cleaning your equipment every 21 days whether it needs it or not. A couple of airstones should do the trick.

Those 20-gallon tubs make some nice grows. Rock on Wayne...

 

[KUSHEATER1]

In my tubs I leave about an inch gap between pot and water no additives and water bottles for temps around 70 and all is well no rot.I found out that if I didnt leave the gap between the pot I would have root rot maybe the pots need that gap so all your roots are not submerged all the time...

 

[FreezerBoy]

Upper roots are air hogs. Plant a seedling too low, it will stop growing while it sprouts new roots at the surface in search of air. Constant submersion should be OK with enough DO but, again, those upper roots want air more than water or food and massive amounts of air to the roots is the point of DWC. I don't maintain an inch but always make sure there's at least an inch. Not that I recommend it but, I've let the gap go 6 inches and more just to see. Plant didn't mind a bit.

 

[KUSHEATER1]

good to know...