<a href=showthread.php?s=&postid=7031381#post7031381 target=_blank>Originally posted</a> by thereefgeek
Flow, flow, flow. You probably should add some more powerheads. I'm running about 4600 gph in my 200 gallon tank.
Also, start with removing the slime manually as often as it shows up. RO/DI usually doesn't relate to how much nitrates are in the tank. You should test the source (fresh product) water pre & post filtration to make sure the filters are working proberly. Depending on where you live the tap water could be better or worse, and the worse the water coming out the faucet, the more frequently you need to change the Carbon & Sediment prefilters and the DI post filters. In my area the prefilters are only good for about 500 gallons so I change them every 3 months. I test the TDS (total disolved solids) of my finished product water frequently to let me know when my DI resin needs changing. RO membranes should also be backflushed every once in a while to help them work at maximum efficency, otherwise they clog up and don't work as well. A cheap TDS meter is $15 and lets you know a lot about the water you use to mix salt. Usually red slime can be traced back to bad source water, but over feeding the tank can be a whole other problem. Be sure to keep the skimmer and the air intake for the skimmer clean so it works like it's supposed to.
It's always best to figure out what's causing the problem, not to add some "Wonder Chemical" to try and fix it.