I am looking into switch to RO water as opposed to using straight tap water for my salt water tank. I’m having a hard time getting nitrate levels down due to the fact that the tap water contains 10-20ppm nitrate. I had an over feeding incident while I was out of town which sent my nitrates through the roof. I’ve been able to get them back do around 40ppm but would like to go lower. Any suggestions on a system that works well and is affordable?? I have a 46gal bow front with aqueon quietflow 400gph filter and a cpr backpack protein skimmer.