legallyflying
Well-Known Member
OK peeps.So in an effort to finally find out the difference between all the different air stones on the market and everyone's personal preference I decided to borrow the extremely expensive DO meter from work and put 7 different air stones to the test.
THE STONES
OK we have an assemblage of the common airstones.
we have the following:
4" round bubble disc. This is a flat disc with a grey sintered stone. the airlline attaches to the side and it stays on the bottom. they run about $8 online.
6" blue airstone..these are the common cheap airstones that are available everywhere. they are dirt cheap around $1. They are made out of fragile blue stone that is known to disintegrate and fall apart after about 6 moths.
micro diffuser. These are insanely expensive I have the smallest one at it cost me $20 online. theya re made from a very high quality material that is very hard and has very tight pores. The tight pores make llots of tiny tiny bubbles. They also creat a lot of back pressure on your pump which means it works harder and less air passes through the stone. These things would likely last forever. The hype is that the extremely small bubbles infuse more air into solution.
4" blue airstone- smaller version of the common 6" blue airstone detailed above.
2" round cylinder airstone, I dig these things, they have a ton of surface area, they are tough (tougher than the blue airstones, they are heavy, and they pass a shit load of air.
2-6" blue airstones on a single hose, pretty self explanatory. some people run two stones in one bucket. wanted to see if there is something to that.
4' bubble hose. these are super cheaply made hoses with tiny holes in them that diffuse the air. I hate this thing, mostly because of the two I bought, one had inets on both ends. and the other one had an inlet so narrow that I had to use a pipe cleaner to actually clamp on the airhose. ANNOYING.
THE TEST
Pretty simple. I had 6 4 gallon buckets and one five gallon bucket all filled with equal amounts of water. All the stones are driven by a large, 110 L/min commerical air pump. Its a big bad ass pump. The hoses are connected to a 12 outlet splitter. All but two of the 12 outlets had air stones on them. I opened the empty ones just a little bit as to simulate a "normal" pump.
I ran the stones for about 10 minutes, then shut them all off, and then measured the DO levels. I then added an equal amount of hot water to each bucket to test at a higher temperature, then did it all over again to test it at an even higher temperature.
A word about the DO meter. Although it is a high sensitive device and it was calibrated, much like a ppm meter, it is prone to drift around a little bit. I did my best to let it settle down and take the correct measurement.
I measured DO content at the following temperatures.. 67.5, 77, and 82.5 degrees F.
RESULTS
Like a proper geek, I put the results in a excel spreadsheet and made a chart..just easier in the end. All results are in ml/L
Here are some pictures of the stones "in action"
Discussion
So as you can see, there is barely a difference between measured DO levels between the different stones. There was a slight difference between them but we are talking about tenths of a ml. There were a couple stand outs, and losers. The 4" blue stone did score the lowest at every temperature. Also, somewhat surprisingly the dual 6" blue airstones actually performed WORSE than the single 6" blue stone.
Also of note was the "super mega micro diffuser" the gold standard of airstone..I mean, its got micro fucking bubblles man! ..scored middle of the pack. Going to pass on more of those.
The 4' bubble line or whatever, despite the fact that it tested well, I'm somewhat leary of the results. I filled that bucket after the first round of testing so the water may have been a little colder. looking at how much air it was moving, I thought to myself that there is no way the readings were correct. Plus, it is a cheaply made piece of shit that the air hose doesn't even fit on without tying it on..
Some other factors to think about..
The 6" blue stone and the 2" round stone moved much more water than all the other stones, it was visibly more. I mean the water was just boiling. The lowest water movement came from the bubble hose and the micro diffuser.
I am using a pretty strong pump, a really strong pump really. The commercial pumps are pretty awesome and if you have a couple of reservoirs or buckets, they are wellworth it. I think that 110 cost me $80 online. That's a 1/4ounce of bud people...just spend the money. My point being that the airstones may perform different with lower airflows. But if you can get the same results by saving shit tons of money on the actual air stones..it may be worth it to buy a proper airpump.
CONCLUSION
If you look at the results, you can see the single biggest factor is actually the temperature of the water. Which is not a huge surprise as warmer water holds less air in solution. If you have individual buckets, insulation is probably the best bet. I have a central reservoir (ebb/flow controller) so I can empty the buckets every couple hours and chill the water for 15 minutes using a dehumidifier coil and pump it back into the buckets.
What am I going to do for airstones? Well its pretty obvious to me is the cheap old standby..the 6" blue airstones. They are a buck a piece so when your done with a cycle, you can simply pitch them and buy new ones. For me that means $16 every 3 months as opposed to $320 for 16 of the micro diffusers.
The 2" round stones are also a favorite of mine. They scored well and they moved allot of air and water. They are much more durable than the blue stones. They do clog up after 2 months in organic nutes, but I dunked them in strong bleach water and they came right back to life. I am not going to use 2 airstones like I previous thought of as they moved less air and water than a single stone. Why? likely due to reduced pressure.
I'm actually going to sell the diffuser on e-bay. It is simply not worth the money I paid for it.
I hope you found the test informative and helpful. I was actually pretty surprised at how even the scores were. Seems like everyone always hemms and haws over which air stone to use when in actuality, it doesn't matter a how lot.
Cheers and happy growing.
THE STONES
OK we have an assemblage of the common airstones.
we have the following:
4" round bubble disc. This is a flat disc with a grey sintered stone. the airlline attaches to the side and it stays on the bottom. they run about $8 online.
6" blue airstone..these are the common cheap airstones that are available everywhere. they are dirt cheap around $1. They are made out of fragile blue stone that is known to disintegrate and fall apart after about 6 moths.
micro diffuser. These are insanely expensive I have the smallest one at it cost me $20 online. theya re made from a very high quality material that is very hard and has very tight pores. The tight pores make llots of tiny tiny bubbles. They also creat a lot of back pressure on your pump which means it works harder and less air passes through the stone. These things would likely last forever. The hype is that the extremely small bubbles infuse more air into solution.
4" blue airstone- smaller version of the common 6" blue airstone detailed above.
2" round cylinder airstone, I dig these things, they have a ton of surface area, they are tough (tougher than the blue airstones, they are heavy, and they pass a shit load of air.
2-6" blue airstones on a single hose, pretty self explanatory. some people run two stones in one bucket. wanted to see if there is something to that.
4' bubble hose. these are super cheaply made hoses with tiny holes in them that diffuse the air. I hate this thing, mostly because of the two I bought, one had inets on both ends. and the other one had an inlet so narrow that I had to use a pipe cleaner to actually clamp on the airhose. ANNOYING.
THE TEST
Pretty simple. I had 6 4 gallon buckets and one five gallon bucket all filled with equal amounts of water. All the stones are driven by a large, 110 L/min commerical air pump. Its a big bad ass pump. The hoses are connected to a 12 outlet splitter. All but two of the 12 outlets had air stones on them. I opened the empty ones just a little bit as to simulate a "normal" pump.
I ran the stones for about 10 minutes, then shut them all off, and then measured the DO levels. I then added an equal amount of hot water to each bucket to test at a higher temperature, then did it all over again to test it at an even higher temperature.
A word about the DO meter. Although it is a high sensitive device and it was calibrated, much like a ppm meter, it is prone to drift around a little bit. I did my best to let it settle down and take the correct measurement.
I measured DO content at the following temperatures.. 67.5, 77, and 82.5 degrees F.
RESULTS
Like a proper geek, I put the results in a excel spreadsheet and made a chart..just easier in the end. All results are in ml/L
Here are some pictures of the stones "in action"
Discussion
So as you can see, there is barely a difference between measured DO levels between the different stones. There was a slight difference between them but we are talking about tenths of a ml. There were a couple stand outs, and losers. The 4" blue stone did score the lowest at every temperature. Also, somewhat surprisingly the dual 6" blue airstones actually performed WORSE than the single 6" blue stone.
Also of note was the "super mega micro diffuser" the gold standard of airstone..I mean, its got micro fucking bubblles man! ..scored middle of the pack. Going to pass on more of those.
The 4' bubble line or whatever, despite the fact that it tested well, I'm somewhat leary of the results. I filled that bucket after the first round of testing so the water may have been a little colder. looking at how much air it was moving, I thought to myself that there is no way the readings were correct. Plus, it is a cheaply made piece of shit that the air hose doesn't even fit on without tying it on..
Some other factors to think about..
The 6" blue stone and the 2" round stone moved much more water than all the other stones, it was visibly more. I mean the water was just boiling. The lowest water movement came from the bubble hose and the micro diffuser.
I am using a pretty strong pump, a really strong pump really. The commercial pumps are pretty awesome and if you have a couple of reservoirs or buckets, they are wellworth it. I think that 110 cost me $80 online. That's a 1/4ounce of bud people...just spend the money. My point being that the airstones may perform different with lower airflows. But if you can get the same results by saving shit tons of money on the actual air stones..it may be worth it to buy a proper airpump.
CONCLUSION
If you look at the results, you can see the single biggest factor is actually the temperature of the water. Which is not a huge surprise as warmer water holds less air in solution. If you have individual buckets, insulation is probably the best bet. I have a central reservoir (ebb/flow controller) so I can empty the buckets every couple hours and chill the water for 15 minutes using a dehumidifier coil and pump it back into the buckets.
What am I going to do for airstones? Well its pretty obvious to me is the cheap old standby..the 6" blue airstones. They are a buck a piece so when your done with a cycle, you can simply pitch them and buy new ones. For me that means $16 every 3 months as opposed to $320 for 16 of the micro diffusers.
The 2" round stones are also a favorite of mine. They scored well and they moved allot of air and water. They are much more durable than the blue stones. They do clog up after 2 months in organic nutes, but I dunked them in strong bleach water and they came right back to life. I am not going to use 2 airstones like I previous thought of as they moved less air and water than a single stone. Why? likely due to reduced pressure.
I'm actually going to sell the diffuser on e-bay. It is simply not worth the money I paid for it.
I hope you found the test informative and helpful. I was actually pretty surprised at how even the scores were. Seems like everyone always hemms and haws over which air stone to use when in actuality, it doesn't matter a how lot.
Cheers and happy growing.
