Yes, we make one that is rated to 1000l (about 250 gal). It uses a small powerhead to dissolve bubbles in a reaction chamber, it comes complete with a powerhead. FWIW, it was my invention and I have a lot of experiene with it. I use it on my 180 plant tank, you can see pics of my tank in my gallery. It takes about 6 bubbles a second to maintain a pH of 6.75 in that tank. When I am out of CO2 the pH is 8.12 and the GH and KH are about 6 each. The only problems (things I want to change) are that the pump gets clogged with leaves and then the bubbles choke the pump and it stalls and sputters and makes a lot of racket, in the 1.5 years I have had mine I already killed one pump. In smaller tanks with lower doses it should do better because 8 bubbles is the absolute limit of this thing and when it died I was doing between 8-10 as my KH and GH were higher at about 8 and I had more dense growth. They are cheap- $27.34. No dealers except some LFS have picked them up yet, they came out in November of last year. They weren't in a catalogue until this new one. Any dealer could order it for you, I do have them in stock.