Quantitative Airstone Test. an end to the hype

to measure the amount of air present in bubbles you could measure the increase in volume when the pump is turned on. The bubbles make this harder by making the surface rough so you'd probably want to measure the level in a side tube without bubbles in it. The best test would of course be to grow a large number of clones in as close to identical conditions as possible except different air stones, but I bet you'd need a huge number of clones to observe a statistically significant difference other than from clogging rate.

It's not the amount of air.. that is easy its printed on the pump. It is the effeciency of air transfer to the water by different sized bubbles and the degree of turbulance.

Or I could just use the round sintered stones and forget about all the jazz

Hey guys. I'm new around here and I have always used the 6" blue air stones. They seemed to work better then the straight ones for me in my 4 gal DWC's.

That being said. I am going to go to a larger reservoir soon and will be buying one of these.

I watched a video on Youtube about the Venturi effect and this looks like a good way to keep nutrients from settling and also blast some serious air into the water. A lot of people use this style pump for fish ponds because they work so well.

Anyways, I just wanted to pass off some info and hopefully this pump will work in my reservoir better then the air pump and stone method.

[video=youtube_share;2OwSfebg-TI]http://youtu.be/2OwSfebg-TI[/video]

Sounds like marketing bs (regarding to the pump above), for $22 I'd be surprised if it works better, but sure would have been nice to get some measurements with this one considering the price. Did you buy it yet and do you use it already?

If anyone is going to test again, I'd be very interested in the DO in a rez in which return water drops/falls from 10" into the rez, for example in an Aeroflo-like or NFT system, and whether that would add something to using air pump + bubble stones.

If I ever get one of those meters I want to try some different types of waterfalls for the return water. I got a water dispenser sort of thing for my cat, it's basically the top half of a sphere with a small pump inside that pumps the water through the center to the top which then surrounds the sphere with a thin waterfall. Not sure how effective that is, probably more about keeping it to a minimum level than adding oxygen, but it significantly reduces the sound as well. If I place the top half of the sphere about half an inch below the return exit, and still half it a few inches above the water level in the rez, I could have a thin hollow cylinder of water drop back in the rez.

Aeration by waterfall is the most commonly used aeration technique overall for enclosed water sites like aquaculture. Yes I know people use aeration equipment directly into the water. But water falling through the atmosphere is well aerated if the fall is adequate. Roiling water where the flow enters is a sign you have enough flow to aerate at least that area of your water. I used an evaporative cooler pump - waterfall system to aerate a 500 gallon stock tank I had put crawdads in. Never encountered an oxygen problem, just an acute buildup of nitrogenous waste that was not adequately disposed of by replacing 1/4 of the water volume daily per LSU.

hotrodharley said:

But water falling through the atmosphere is well aerated if the fall is adequate.

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The thing I'd like to know/measure in particular is the difference between the effect of creating max roiling opposed to spreading the waterfall as thin as possible to increase it's surface area while falling (also spreading the coiling, not sure what that does with the coiling total, I'd guess make it less and quieter).

In my case the water pump timer settings would play a huge role as well, for example during night time if it sprays less often with longer intervals between it.... not going to work, unless I use a small water pump just to create the waterfall. Which would raise a waterfall through water pump vs air pump +bubble stones question.

I think obviously the thinner the sheet of the fall the greater the ability of the water to absorb O2. Oxygen is a very friendly molecule and likes to attach itself to another O molecule or a myriad of other elements. The folks at LSU that helped me long distance were the ones who proposed the waterfall for aeration. Along with replacing 1/4 of the total volume daily. They advised against a greater change due to pH and O2. Didn't quite work. We had to eat over 200# of crawdads that night. People got gunny sacks full dropped anonymously at their doorstep.

hotrodharley said:

I think obviously the thinner the sheet of the fall the greater the ability of the water to absorb O2. Oxygen is a very friendly molecule and likes to attach itself to another O molecule or a myriad of other elements.

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Thanks for educating me on that - I should have paid more attention in physics class. Makes sense though. Would it still need an air pump because it's enclosed? With the bubbles the water touches fresh air, with just a waterfall...

Made some pics of the pet water dispenser thingy I mentioned earlier. The flower-shaped thing at the top happens to fit up side down, with some minor work, in my return hose, first splitting the stream in six before spreading it over the flower. Obviously that would create some coiling as well. The bowl works best with a certain amount of water so probably won't match.

This gives me another idea that might work for my rez as well as DWC buckets. It could be a lot more quiet compared to bubbles, wouldn't require a powerful air pump but a simple water pump. To take a DWC bucket as an example, see attached image. Basically create a waterfall inside the rez, along the entire wall by overflowing a small gutter. Could that work better than air pump +bubble stones? In a DWC setup it would require a pump per bucket or a separate rez for the pump and then interconnect all buckets to keep the water level... but for the rez in my setup it would be easy to setup. Just a small water pump to fill a gutter along the inner walls of the box. Stretching the gutter down as in the left image (the purple thingy) would reduce splatter, using just the gutter part at the top would create more coiling. Instead of overflowing the gutter it could be a helix, like round stairs along the inner side of the bucket wall.

Or/and... add a sprayer or two more to my system but place them back in the rez... sounds simple and effective.

I got a few other items I need to buy before my first hydroponic setup is complete, but I'm definitely getting the DO meter in a few months. The effect of combining methods (or extending the waterfall) won't add up endlessly but it still seems like a fun challenge to increase it with a few points compared to using bubbles.

You might want to try and rent a DO meter. A good one is around $500..

Falling water is a great way to aerate things. I believe that agitator is the correct adjective in this case? Many sewage treatment facilities use agitation to entrain oxygen. That little floating donut in the middles of the sludge pond making all those frapachino bubbles...that's an agitator mixing in O2.

Any simple waterfall or jet blasting into the standing water will provide plenty of oxygen to a reservoir.

The blue stones work fine although the down side is that they are fragile as fuck, and worse after a run or two. You can't get the hoses off without breaking them. Trying all the different stones etc ...and this is for DWC plant containers, not reservoirs, the round grey stones seem to provide the bet bang or the buck.

They put off a lot of air. The bigger, more expensive 4" ones don't do any better than the smaller ones, they are durable as hell and you can get them for about $2 a piece.

I have about 32 of them now. About the 4th week of flower, before they get completely burried in the root ball I swap them out for clean ones as they do tend to get slowly clogged if your using beni tea.

For the dirty ones...
1. I rinse them off then let them dry
2. Then I boil then for about 2 minutes
3. Let dry again
4. One last boil for about 2 minutes.

The drying/boiling really seems to clean them out well and they are ready to go.

I should have tested air pumps. I used to think that air pumps had to be hot and loud...ala the ecoplus commercial. Well I bought a 150 liter? Alita style air pump from eBay "pond master". Holly fucking shit these things are awesome! Sooo much air, higher PSI, quieter than my oscillating fans, and they only get to about 95 degrees. The Eco plus got up to 138 degrees!

Cheers

I don't know if agitation refers to adding oxygen specifically or if it is merely a side effect of agitating (mixing fluids, like a washing machine agitator), but I considered using a wavemaker (for aquariums) to increase the motion. I would be placing another warming element in the rez so figured I'd better spend the money wiser but for example: http://www.amazon.com/1300-Coral-Aquarium-Makers-Powerhead/dp/B002480V32/

Makes me wonder if creating a whirlpool in a DWC bucket by a rotating fin at the bottom would work - would obviously need good protection against roots but could be very quiet. Might even do good pressing the nutes against the roots continuously.

legallyflying said:

I should have tested air pumps.

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Or the same pump on different volume of water and try and work out a rez to air pump capacity ratio. How much would it for example have mattered if you had the same bubble stone in half (or double) the amount of water. Continuing to reduce the amount of water to a minimum should also give an indication of what the max feasible DO would be using an average air pump + bubble stone method. Seems a little pricy to actually test a bunch of different pumps but it sure would be interesting.

Renting a DO meter, that's a good suggestion. Not sure if I can find something in my area that rents to consumers, but a quick search shows there might be options. I noticed the $140 Milwaukee DO meter, would it not be good enough for a test? I guess the cost of the others listed sort of answers that question already.

Getting my rez in tomorrow, then I'll know the height of the return waterfall 'inside the rez' as well. I think I'm going for something like a gutter on the inside of the rez in which the return water drops, and maybe use a small 12v pump I already have to keep it going non-stop.

I think your thinking about it too much. You know how I aerate my 70 gallon rez?

I have a $10 water pump that shoots water straight up through a 3/4" hose and then it splashes down into the water. done and done.

legallyflying said:

I think your thinking about it too much. You know how I aerate my 70 gallon rez?

I have a $10 water pump that shoots water straight up through a 3/4" hose and then it splashes down into the water. done and done.

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That's how I did my crawdad farm. Swamp cooler pump - water up 9 feet and shot out to fall back down aerated. Cheap and suggested by Louisiana State University.

legallyflying said:

I think your thinking about it too much. You know how I aerate my 70 gallon rez?

I have a $10 water pump that shoots water straight up through a 3/4" hose and then it splashes down into the water. done and done.

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Yep, no sense in trying to reinvent the wheel so to speak. Sometimes people tend to over complicate a fairly simple process as growing MJ.

Not to beat this horse anymore... but, i read a test done by max yield magazine cOncerning DO.According to them the saturation point of oxygenation is something like 6ppm. They were able to achieve supersaturation by adding a venturi to the existing aeration methods @ a final reading of 8ppm. I used a venturi on the return pump of my UC hybrid project and i can see bubbles forming on tons of submerged surfaces... its actually kind of cool

Excellent comparison write up 10/10

nick88 said:

Yep, no sense in trying to reinvent the wheel so to speak.

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That expression should have been deleted from history after tank treads were developed. No seriously, you guys are probably right.

It just seemed attractive to combine two or more easy/simple methods, if it were to increase the values noticeably. But besides I won't be able to notice a small difference without a meter, it seems the max saturation point using easy/simple methods is reached even sooner than I at first expected - I'd probably just end up making a bigger mess with more noise.

I'll just keep it simple then, thanks for indulging nevertheless!

JordanTheGreat said:

I used a venturi on the return pump of my UC hybrid project and i can see bubbles forming on tons of submerged surfaces... its actually kind of cool

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That does sound kinda a cool as well as a reassuring sign.

Sorry to bump an old thread, but I have searched the airstone debate, and I have yet to find any info about hose diameter. This gets more into fluid dynamics and pressure but why is there no talk of air hose diameter? These airstones have 1/8 in intakes. I choose the micro diffusers because most of them come with a 3/8 inch intake option, meaning I can push air at a wider diameter, hopefully pushing more O2. Sure the tube goes down to 1/8 at the diffuser, but isn't it better to push a larger volume of air to the diffuser? I've searched, but there isn't much on this. Maybe I've missed something.

Turkey, it gets really complicated fast but you can calculate it. The big thing is how well your pump fights against back pressure. Small hose isn't that bad, but long lengths of small hose are. When I had a 12' long grow room with double rows, I ran 3/4" line to a t and then ran 3/4" to each of the two manifolds.

Now that my room is 25 x 15 I run a single 3/4 inch irrigation hose around the room. Then I just tap into it with the individual air stone lines. Nice even pressure that way and short lengths of small hose.

If you are running less than say 5' I wouldn't sweat it.

I wonder if different airstones would have more of a noticeable change in effectiveness if you weren't blowing up your buckets with 110 L/min. At that rate, could prob just stick the hose in the bucket and reach saturation.

I only read the OP, sorry if this has already been addressed.

Perhaps. But the largest take away, for me anyways, is that total saturation is pretty easy to achieve. So spending your money on diffusers or micro pore stones is probably just a waste of money. Same with vortex and ways to achieve higher than normal saturation. There is a pint where there is TOO MUCH OXYGEN!! It will start messing with your roots. I was running a UC and having problems. I called UC and he said "shit, your putting like 4 times the recommended amount of air in the system. I scaled down and the problems went away.

Take home point... I'm fucking killing it with 2" round stones and a good pump. You should be able to as well