I'm kind of in your boat. 55 gallon super uber high tech with [censored][censored][censored][censored]ton of plants and mounts of ADA soil. Until last week, I added KH to 2 in my rode water but it basically goes to zero within 2 days. My PH with CO2 on is between 5.5 and 5-6 and fish/shrimp are doing fine. I think I'll just stop raising KH and see what happens.