How much GFO?

[Slyguy00]

holy! lol thats alot. I never trust that BRS calculator. When i first started using it I always did half of what it recommended. Now that I know what my tank consumes, I dont even use it anymore.

[jason604]

What? 2 cups for a 90g?!! That's massive. Mybe they want u to crash so u can buy a whole new system from them lol

[gregzz4]

The BRS calculator states I should use .86 cups for my system.
That's about 225mls.
I've been battling algae for over a year and decided to back off my GFO amount.
I'm down to 100mls/month and the algae is under control.
I feel the added Iron from the GFO was part of my issue, not the GFO stripping the system as I've always had some measurable PO4.

[lastlight]

The calculator told me 1 cup and I thought oh good that's how much I use. They suggest replacement every 4-8 weeks and I've been doing it weekly lol. Might have to test after a week is up to see if this is justified.

[Reef Pilot]

I don't go by any calculator, just what fits nicely into my refillable canister cartridge which is about 250 ml.This is for a 230g system. I use HC GFO. It last about 2 months for me.

I try to keep my P04 between 0 and 0.04 (Hanna). After a change my P04 goes to zero. I check every 2 weeks or so. When it climbs to 0.04, I stir it up in the canister and it then returns to zero. I usually do this 2 times with the same batch. If it doesn't return to zero, then I know it is time to change.

This routine has been very consistent for me. And keeps my GFO costs down. And my P04 doesn't get out of hand. I find best SPS color and growth at these low levels of P04.

Last year I had some tank troubles and my P04 jumped up to as high as 0.10, and had to increase my GFO changes to get it back down again. My SPS lost color, and growth really slowed. I should mention that some SPS are affected more than others. Some didn't seem to be affected at all. But no question, overall and in general, all SPS does better with low P04.

[mikellini]

Originally Posted by gregzz4

The BRS calculator states I should use .86 cups for my system.
That's about 225mls.
I've been battling algae for over a year and decided to back off my GFO amount.
I'm down to 100mls/month and the algae is under control.
I feel the added Iron from the GFO was part of my issue, not the GFO stripping the system as I've always had some measurable PO4.

Have you thought about using phosguard instead? Or alternating between the two? I know there has been some concern about elevated aluminum levels, but now we've seen Triton tests that show elevated levels of aluminum in some salt mixes (with no obvious ill effects) and other tanks running aluminum phosphate remover with normal levels of aluminum in the water column.

Basically I'm just giving myself a pep talk here because I'm going to use up some Seagel I have laying around (mix of phosguard and matrix carbon).

[duncangweller]

Wowee, thanks for all the advice.

Whilst I've got your attention....the BRS calculator also says to use 0.84 cups of carbon. Is this also way off base?

Thank again guys... Such a useful bunch

Dunc

[jason604]

Originally Posted by duncangweller

Wowee, thanks for all the advice.

Whilst I've got your attention....the BRS calculator also says to use 0.84 cups of carbon. Is this also way off base?

Thank again guys... Such a useful bunch

Dunc

Sounds about right.

[jason604]

Here's a pic of how many of my sps died(so did a bit of me) from using too much Gfo too fast. I now bleached and acid bath it and use It as extra filtration in my sump( very very VERY EXPENSIVE filtration)

[Myka]

1 tbsp per 30-50 gallons is a reasonable place to start. I've used this amount in a dozen different tanks.