How much Rowaphos would you start with?

[diverjm]

I have a 32 gal Biocube (probably more like 26-27 gal with rock displacement) with ultra high phosphates averaging 0.5-0.6. I just recently got Rowaphos and wondered what amount should be used without a reactor to bring phosphates down to a manageable amount? I plan on using the mesh bag included with the 250g container sandwiches between two filter floss pads.
@Randy Holmes-Farley

 

[Randy Holmes-Farley Verified Community Expert]

Is water being forced through the bag?

Assuming so, I always recommend going slow and so might suggest 1/4 cup.
Ye

 

[diverjm]

Technically it’ll be between filter floss on the top rack/shelf of my intank media basket. Water cascades on top of it via a water director as seen in attached images.

 

[diverjm]

According to an online calculator I found, with the specs of my tank size, Phosphate levels, and used

through a reactor I should use 5 TBS. I know it is quite a bit less effective using it the way I’m proposing yet I don’t want to bottom out my phosphates.

 

[rishma]

I suggest you don’t want as low as 0.03 ppm. That is low enough it’s difficult to test for and too close to 0.00. I like to target about 0.1-0.2.

There is no such thing as reducing phosphate too slowly. Reducing it too quickly is a commonly associated with issues if you have coral in the tank.

I wrote up a thread some time ago for the rare times I use phosphate removing media in a small water volume. You might find it helpful.

A way to use GFO to slowly and sustainably lower phosphate

GFO works and there is nothing innovative here, but perhaps this will be helpful to others. I previously struggled to get good results with GFO in small water volumes. I keep a stable PO4 range around 0.08 ppm most of the time with carbon dosing (NP bacto), skimmer, and consistent food...

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