is my kh too high for my co2???

A word of advice before you go out and buy a RO unit.

Plants want what? CO2 or a certain KH? A certain pH? They care about CO2. Whatever combinations that gets 20-30ppm will suit you.

If your KH is 10, then a pH 7.0- 7.1 range is good. If your KH is 3 then 6.5 -6.6 range is good and so on. Both yield the same amount of CO2.

Now an RO unit is fine if you want to reduce the salts in your tap water for drinking, it's better than buying bottled water for 1$ a bottle etc.
Or if you want to breed certain fish, but it's not for the plants.

RO is not for plants specifically, perhaps some other purpose relating to fish, but not plants. You'll find that road full of extra work, added cost and very little fruit for it.

Get a gas CO2 system before you ever consider a RO system.

Regards.,
Tom Barr
 
AquariaCentral.com