Who Gives A Fish Forums

My nitrates are sitting at 20 ppm and I'm not sure how to bring them down. I've got a 75 gallon tank with a mix of LPS and softies, running a protein skimmer and weekly 10% water changes. Any tips?

20 ppm isn't terrible, but I get why you'd wanna lower it. Have you tried increasing your water change frequency? Bumping it to 15% twice a week might help. Also, what's your feeding routine like? Overfeeding can spike nitrates fast.

Yep, timeon's got a point. I had the same issue in my 90 gallon. Cut back on pellets and switched to frozen, nitrates dropped in a month. Also, adding chaeto in the sump worked wonders for me.

Glad you're open to suggestions! Another thing to consider is your flow. Low flow spots can let detritus build up, which breaks down into nitrates. Maybe tweak your powerheads or add a wave maker?

I run a refugium with mangroves. Nitrates stay under 10 ppm. Might be worth looking into if you've got the space.

dorvex wrote: ↑Tue Jun 17, 2025 3:12 pm I run a refugium with mangroves. Nitrates stay under 10 ppm. Might be worth looking into if you've got the space.

Mangroves are solid, but they grow slow. Chaeto's faster if you need quick results. Also, what's your skimmer rated for? Might need an upgrade.

True that. My skimmer's rated for 100 gallons, but I've got it on a 90. Nitrates haven't been an issue since I dialed it in. Oh, and don't forget to clean your filter socks if you're using 'em.

Filter socks are nitrate traps for sure. I swap mine every 3 days. Also, how old's your substrate? Sand beds can leach nitrates if they're too deep or old.

Lots of great ideas here. Gonna start with more water changes and chaeto. Thanks, everyone!