High PO4 (1.2) even with Algae scrubber

[tc2007]

So I have been running an algae scrubber rated for 250G and my tank is 90G volume overall. It's working nicely and I remove a cup full of algae every month. Apparently it's not enough as my PO4 today was 1.2+ after 3 months of harvesting. Anyone know how long it should take for PO4 and NO3 to be within acceptable params? My NO3 is 32ppm.

My bioload is light with one small yellow tang and about 5 small fish and inverts.

I feed 2 cubes of Piscine mysis some days or flakes otherwise. I only feed once. To my these readings are too high.

[bertoni]

Phosphate is consumed in relatively small proportions (compared to carbon and nitrogen), so I wouldn't count on the scrubber reducing the phosphate level very quickly. If the input rate of phosphate is high enough, and two cubes might be enough, the scrubber might just barely be keeping up. Has the nitrate level dropped any?

A cup of algae per month is not very much for that size tank. I don't know how big the cubes are, but you might want to cut the feeding in half.

[tc2007]

Those are standard sized cubes. I was really counting on the scurbber

Don't think the nitrates have gone down too much either. I think I need to start harvesting every week or 10 days so it grows back again.

[mcgyvr]

2 cubes seems excessive...

[bertoni]

I think that does sound like a lot of food, depending on the size of the tang. Maybe add an algae clip and cut back on the frozen food.

[hkgar]

I feed heavy, my Atlantic Tang and Two Bar Rabbitfish eat 1 large romaine lettuce leaf daily and I feed 9 grams of frozen home mead food + 4 pinches of pellet food 4 time/day.

I use an algae scrubber and dose carbon to remove nitrates and phosphates. My nitrates are about 5 and PO4 .02 (if it starts going up I run GFO for a few days.

How large is your screen and what is your lighting for the screen, plus light schedule?

[Scrubber_steve]

Originally Posted by tc2007

So I have been running an algae scrubber rated for 250G and my tank is 90G volume overall. It's working nicely and I remove a cup full of algae every month.

Apparently it's not enough as my PO4 today was 1.2+ after 3 months of harvesting. Anyone know how long it should take for PO4 and NO3 to be within acceptable params? My NO3 is 32ppm.

My bioload is light with one small yellow tang and about 5 small fish and inverts.

I feed 2 cubes of Piscine mysis some days or flakes otherwise. I only feed once. To my these readings are too high.

I was really counting on the scurbber

Don't think the nitrates have gone down too much either. I think I need to start harvesting every week or 10 days so it grows back again.

Scrubbers are not sized according to tank volume, but according to the amount of food fed to the tank - cube equivalents.

You need 12 square inches of screen, illuminated on both sides buy the correct spectrum & intensity, per cube of food fed daily.

The screen should be harvested every 7 to 10 days, generally speaking, for maximum efficiency.

Depending on the efficiency of the unit overall, the level of po4 & no3 you want to maintain the system at will determine the illumination, or photo-period run. It can be run from 7 to 24 hours a day.

If the unit is of good design & suitably sized for the system, running a 24/7 photo-period will reduce excessive nutrient levels & assimilate the added daily load as well.
Harvesting the screen more often than every 7 to 10 days, in this scenario, will help reduce excessive nutrient levels.
But it takes time & lowering excessive nutrient levels by doing water changes would be the best solution.

[hkgar]

How much screen and how much light Use this calculator

[five.five-six]

Mark is a bit of a goofball, you can skip to 3:30. And I’d stick to the 0.5/day

[youtube]7x8bmqx9NOM[youtube]