I want the nitrates low mostly so I can have things healthy for my existing corals and also be able to try out other corals in the coming months. Even though I'll probably stick with softies for some months to come, the current 20 ppm seems high for recommended coral keeping.

Water flow is as high as I can get it without blasting away my softies and feather duster. Two koralia 1's at 400gph each (which is alot in 30 gallon tank), and canister filter (up to 66 gal tanks) at about 116 pgh, and hob skimmer and hob refuge.

The canister filter was about 6-7 weeks old and hadn't been cleaned, so I cleaned it out over the weekend. Didn't seem very dirty and not clogged up.

My skimmer is aqua-c remora, rated up to 75 gal tanks. I empty and clean the cup a couple times a week. There will usualy be less than 2 inches collected in the cup (weakish tea colored i guess, i don't drink tea), but the neck gets gunky so that's why I clean it out more frequently.

Thanks to Ace, I've added some more macro algea, so that can help with nitrogen export. It just seems that perhaps because my small tank size with 4 fishes, nitrates are always staying around 20 ppm; even with weekly water change. The large clown (and cleaner shrimp) is very agressive feeder, so I try to feed enough the that bi-color blenny and neon gobie still get a few bites.

So I'll watch a few more weeks. continuing regular maintenance, cleaning the canister monthly, feeding somewhat less; and see if things improve. Spending lots of money is not something I would like to do, so that rules out larger skimmer, installing RODI unit, nitrate reactor, etc.