Algae Scrubber - Nitrates not falling

dwair · Sep 24, 2020

So I've had the Clear Water 50 Scrubber running for about 2 months. Before this I had the Tunze Macro Algae Reactor, Used it for about 3 months, while using each one, my Nitrates never drop below 20, most of the time staying around 50. I'm cleaning the screen on the scrubber about once a week and its filled with dark thick algae. So I know its "working".

I'm only feeding twice a day, I was feeding once a day to see if that made any difference. It didn't.

I'm also using a Reef Octupus 150 Classic Int. Its pulling dark sludge, besides that its just 2 felt filter socks.

Waterbox 100.3 (75g display). Phosphates been around .1 this whole time, I've had to dose them to get them to .1, but once I did, they've stayed there.

Short of buying a new sump to run a Refugium, any suggestions on how to get these nitrates down?

ThePurple12 · Sep 24, 2020

Are any of the inhabitants unhealthy due to the nitrates? If not, I would just leave it.

I think the main explanation would be the scrubber isn't big enough to handle your current stock.

Pistondog · Sep 24, 2020

as an experiment, maybe lose the filter sox for a month.
Some say they are nitrate sources since they are temporary and have no bacteria.
I took mine out 15 months ago, cause lazy.
Vs encouraging bacteria growth to handle detritus, if no sox.
Plus what thepurple12 said.

ca1ore · Sep 25, 2020

Ultimately it’s about input/export. You say you feed twice a day but don’t say how much. There’s a formula that calculates square inches of scrubber screen to the amount you feed. Seem to recall it’s 10 square inches per cube equivalent, but go check. Perhaps the scrubber is not big enough, or perhaps you’re getting nitrate from the sand or the rocks. Nitrates of 50 isn’t terrible, but it’s not ideal either. You could try carbon dosing.

I have about 120 fish and feed about 20 cube-equivalents per day. Even my large skimmer and ATS cannot keep up so I run a SuRx also.