Originally Posted by ryshark
I do believe what I said about General Hardness is correct that it is more of a freshwater thing.
That is correct.
Buying an RO
unit is one of the best decisions I made when starting out in this hobby.
The bio balls could be part of the issue with high nitrates. I'm guessing you have a wet/dry filter under the tank?? Probably the best thing you could do for your tank is to remove the bio balls and replace them with Live Rock Rubble.