Originally Posted by fishwife
I'm sure this is really basic, but it's the first time I've tried this. Anyway, I'm setting up a diy system with an in-tank power reactor. Am I right to assume that there's no real control over how much c02 you add to the tank with a diy setup? I mean it's just a soda bottle and a tube. How do you make sure you're not adding too much and that you're getting consistent results? It's not like you can turn it off at night.
KH 5 is about as perfect as it can get! They probably wanted to sell you something at the LFS and got pH and kH mixed up. Anyways....
There are a couple of ways to regulate DIY CO2, not fully automated, but pretty close. Most ppl just let it run 24/7, and the outgassing due to surface agitation etc is bigger than the fluctuation because of what the plants use.
If you do notice a CO2 buildup over night and problems in the morning, you can do several things. When using a power reactor (with powerhead, I assume) the easiest would be to put the powerhead on a timer, possibly together with the lights. Just have to be careful with the CO2 buildup, it can lead to airlocks if it can't escape out of the pump.
Or, you could reduce the size of the CO2 DIY bottles so the overall CO2 output is reduced, and will not buildup over night.
Some ppl use an airpump at night which dissipates CO2 from the water column.
Or you can use a solenoid and put it on a T, open it at night, CO2 escapes, close it during the day.
So... it is kind of like you can turn it off at night.