Flood & Drain - Do you need air stones in the res.

Do you need air stones in the res?

The more oxygen the better, so yes use airstones.

angelsbandit said:

The more oxygen the better, so yes use airstones.

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and helps keep nutes well mixed also...

No, you don't need airstones. At least in ebb and flow you don't. I ran a test (more like I was too lazy to buy another pump for another res) for about 9 months where one res had an airstone and one did not. There was zero difference in the performance of the plants, pH stability, etc. Again, this is ebb and flow I'm talking about which by nature oxygenates water as it's working.

thanks for the help homebrewer, thats what i thought.

jake55 said:

thanks for the help homebrewer, thats what i thought.

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I should add that I finally ran out and bought an airstone and pump for the res that didn't have one. Not because it needed it, but I wanted to be consistent across the board.

I've read convincing posts on icmag by a guy who had a dissolved oxygen meter saying that your average aquarium airstone hardly gets any O into the water. The bubble curtain was slightly better and the disc-shaped blue airstone was the best. However, the differences in PPM were surprisingly marginal.

I still use them though because nasty anaerobic shit grows in my rez if I don't. My reasoning is that the rootzone oxygenation in a flood and drain system comes from the flood itself - all air is expelled below the floodline during irrigation and fresh oxygen-rich air is pulled in as the floodline recedes back into the reservoir. So there's little direct effect on the plants if you're flooding with oxygen-depleted solution but there may be a strong secondary effect if you're breeding pathogens in the reservoir. Will you see these secondary effects? Tough to say, it's heavily dependent on a bunch of other factors, but as Homebrewer proved, there's at least one combination of factors where it won't make a difference.

Homebrewer, just for the record, how often do you change out your reservoir? Tap or RO? H2o2? Light-proof reservoirs? These are all things I'd imagine would make a difference in your success without airstones.

lowerarchy said:

Homebrewer, just for the record, how often do you change out your reservoir? Tap or RO? H2o2? Light-proof reservoirs? These are all things I'd imagine would make a difference in your success without airstones.

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Res change once per week. I used tap water at the time of the 'test'. No H202, ever. Concrete mixing tubs as reservoirs but they aren't really covered that well.

homebrewer said:

No, you don't need airstones. At least in ebb and flow you don't. I ran a test (more like I was too lazy to buy another pump for another res) for about 9 months where one res had an airstone and one did not. There was zero difference in the performance of the plants, pH stability, etc. Again, this is ebb and flow I'm talking about which by nature oxygenates water as it's working.

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In a table setup I agree, no stone is necessary, as you have aeration as it leaves the nozzle in the table, and more as it drops back into the reservoir.

But if you ebb-flow with a bucket system I would recommend that you aerate that because I do see a difference in PH stability and settling. With a bucket system, the only aeration and agitation is the return of the solution back to the reservoir 4 times a night.

homebrewer said:

Res change once per week. I used tap water at the time of the 'test'. No H202, ever. Concrete mixing tubs as reservoirs but they aren't really covered that well.

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Totally makes sense, your results vs. mine then. I do a change every two weeks or sometimes three, more than enough time for a bacterial colony to be established.