I just set up a DIY CO2 system for my 35 gallon tank. It is moderately planted and more to come soon. With the set up I made I am putting out about 10-12bpm. I wanted to know if that is good and the best way to diffuse it? Any and all help will be greatly appreciated.
1 bubble every 5-6 seconds is OK, a bit on the slow side, perhaps, but this is one of the limitations of DIY CO2.
There are various methods of diffusion available to you, such as feeding the bubbles into the intake of a filter, or using a glass diffuser with a ceramic disc (not all will work with DIY CO2, however, so be careful when selecting one).
I would say that your rate has nearly no effect on your size of the tank. I would invest into co2 bomb and push at least 1-2 bubbles per second.
If not try to increase the performance. I use for my 20 litres, 250g of sugar, tea spoon of dried yeast and a little less than one litre. It works well for me on such size of the tank.
Over the next couple of days I am going to set up one or possibly two more 2L bottles to increase the flow. I am at least getting something in there now. I have it all hooked up with a check valve and an airstone and the rate it staying steady. I hope with adding one or two more bottles I can double or triple my flow rate.
I did DIY CO2 with 2 bottles on my 29 gallon a while back and I ended up getting Black Beard Algae. Couldn't figure it out because it is a low light tank. Did some research and read somewhere that fluxuating CO2 levels can cause BBA outbreaks. I scrapped the DIY CO2 and the algae went away. I think unless the tank is small your doing more harm then good.
Wow. If you're only getting 10 - 12 bubbles per minute, you might need to check your mixture and check for leaks. With my system, I got 4-5 BPS with two 2L bottles, mixture changed in one bottle every week.