I absolutely love this .. I have 3 in my tank with the corresponding blue lights. I bought these to replace 2 of 3 that I already had in my tank for a long long time. I will definitely continue to buy these as long as I have a working aquarium. My tank is 75 gallons.

All right. I'm giving this five stars because well...it really does produce wonderfully fine bubbles. On the other hand, I want to give it ZERO stars for Hydor's COMPLETE lack of recommended tank sizes for this product. I also want to give it THREE stars for the horrible air control... It seems that they need to have a much better air control valve for this thing and not this little twisty cap thing with a bit of sponge in it. I bought this for my 36 gallon. Even at it's LOWEST setting, the micro bubbles completely overwhelmed my tank and stressed my fish out to the point of hiding. I could've gone out and bought an air control valve myself to see if I could really reduce the bubbles....But at that point, I found just by adding an HOB filter on it's lowest flow rate did the job...aeration wise(my tank's main filter is a canister). I yanked the bubble maker from my tank and said c'est la vie! What size tank would I recommend for this thing? 55 gallons or bigger. When I do get around to setting up my 55 I will be adding this to the tank. It absolutely will do the job oxygenating the water! And beautifully at that!

even on the lowest setting this this thing puts out so many bubbles, causing so much evaporation of the water I'm constantly having to refill my tank. Then there is the too many times it has turned into a siphon and water started streaming out of the air line. I woke up to about 4 gallons lost out of my tank and was freaking out thinking my tank is leaking and I couldn't find the leak spot then I noticed a heavy stream coming from the air line adjuster. This is the 4th time this has happened. I got this because I can't stand the sound of air pumps but I've never had an air pump do this...also got it to aerate the tank at night when the plants aren't using the Co2 so my fish don't get gassed. I now have the line running back into my tank and secured. This thing should come with a huge warming about this

It works pretty good in a 20 gallon tank but the adjustment for just how much bubbling is VERY difficult to control. The air cap is in two halves with an 1/4" cube of sponge inside for a dust filter and the air intake is just a small hole this is opened or closed off by twisting the top half of the cap. Once adjusted is stays but it takes me forever to get that perfect little bit of bubble so the whole tank doesn't become a cloud of bubbles! The sponge has to be cleaned so when you open the cap to wash the dust out of the sponge you have to re-adjust the air flow... AUGH!
But it is VERY QUITE and our 4" long goldfish seem to enjoy it. I did not purchase the LED light but it is a nice, small size and is almost unseen ion the tank floor. I just with I could control the air bubble volume better because it really does take me about 10 minutes of twisting to get it just right.

This beats the heck out of bubble bars or stones. First of all, you don't need an external pump; I love not having that on top of my tank! It isn't completely silent -- there's a low hum -- but it's far quieter than the external air pumps I've had. It also comes with good quality, flexible black air hose. I have a black-backed tank, so I barely see the hose and power cord. Set up was extremely simple, and this little gem is producing a good amount of very fine bubbles, and the amount is easily adjustable. It's a great size for my 36 gallon bow front tank. The bubbles it produces are more like champagne, and less like boiling, which is great because I've had problems with the spray from the bar bubblers blowing up into my LED tank lights and ruining them. This is not getting the light wet.

Seriously, just forget about the bogus air stones -- this is so much better.