6 Inch By 8 Inch 1 Sided Scrubber

[Floyd R Turbo]

It is probably a combination of a few things. #1 is everything that was alive on the rock died, and if you didn't at least soak the rocks in water or powerwash them to remove the dead organic matter, this stuff just goes right into your water when you put it in the tank.

#2 is bound organics and this would be the result of whoever had the rocks prior to you, and their husbandry practices.

You can get rid of #1 by doing a large water change and if you didn't wash the rocks at all, I would do this (the water change, not washing the rocks) just to make things move along quicker. I wouldn't rule out a 100% change really. Just get the fish out and acclimate them to the fresh SW over a few hours and they'll be fine.

But then #2 will take some time, between scrubber and GFO (I prefer Phos-blast from Premium Aquatics, which is RowaPHOS just cheaper) you should be able to get everything under control.

Or, you can just let the scrubber do it's job. With very little bioload and feeding, it should do what rleahaines said - it will mop up N fast, and P will probably still be there - so you're then back to a PWC or GFO/Phos, once your P hits zero pull the Phos remover and monitor

[SantaMonica]

Washing rocks does not remove phosphate, it just kills the life in the rock.

Just let your system run, and nutrients will slow come out.

[Floyd R Turbo]

Oops, I just re-read my post and edited it to read in line with what I meant. I mean if you didn't wash off the rocks initially, I would consider the water change - not taking the rocks out and washing them off now!!

[gtfcniles]

If your nitrates are low, and your phosphates still high, you could dose nitrate to bring the phosphate down.

[SantaMonica]

I wouldn't. There are plenty of nitrates for growth even if you measure zero.

[Greenchaos]

I've read somewhere that algae can grow in 40 parts per billion, for both nitrate and phosphate. Now, that's really low.

[SantaMonica]

Also, algae increase or decrease the ratio of what they consume, to match what is available in the water. That's one reason why the growth changes from dark to light as the nutrients get less.

[Greenchaos]

Also, algae increase or decrease the ratio of what they consume, to match what is available in the water. That's one reason why the growth changes from dark to light as the nutrients get less.

Wouldn't that mean an algae grown in low nutrients actually exports less nutrients than one grown in higher nutrients. Baffled.com.

[Floyd R Turbo]

^^ precisely why I stopped weighing harvests. Growth volume and mass is not being properly interpreted as equal to filtration capability.

[Greenchaos]

Hello Mr. Flyod. Have you been doing this long? Are you saying that algae may grow great but actually export little?