When I was using DIY co2, I absolutely swore by the glass diffusers. I think it is comparable to the bottle/power head option and much cleaner. When I switched to pressurized I simply built a inline diffuser. (2"x12" PVC with two caps. Tapped both ends and put brass fittings with a fitting on one end for airline tubing. I put bio balls inside with removable side to clean. works GREAT! the diffusor is on the inflow side)
As far as turning off a diy co2, you don't... like mentioned earlier, simply shut the power head off or drop an airstone in. This will help rid co2 and increase oxygen overnight.
Keep in mind that your water quality is altered by crushed coral, it doesn't mess it up. If your pH is at 8 and KH is at 4, you have very little co2. Co2, will naturally lower pH and increase co2 level, your KH will remain the same. There are charts available online that will help you determine co2 level by comparing KH and pH.
It is recommended that you aim for 20-30ppm of co2, anything more you risk suffacating your fish
As far as turning off a diy co2, you don't... like mentioned earlier, simply shut the power head off or drop an airstone in. This will help rid co2 and increase oxygen overnight.
Keep in mind that your water quality is altered by crushed coral, it doesn't mess it up. If your pH is at 8 and KH is at 4, you have very little co2. Co2, will naturally lower pH and increase co2 level, your KH will remain the same. There are charts available online that will help you determine co2 level by comparing KH and pH.
It is recommended that you aim for 20-30ppm of co2, anything more you risk suffacating your fish
