GFO question... how much?

SashimiTurtle · Jan 3, 2020

I usually only run my refugium for nutrient control, but my last water test came back with 0ppm NO3 and 0.3ppm PO4. So, I have a phosphate problem, evident by the ulva algae problem. Algae I can handle, I'll get some more CUC and I've done a very large WC today and scrubbed rocks.

How much GFO should I put in my reactor? I dont want anything aggressive. Just a little to lower phosphates slowly and keep them down. I have a 90 gallon cube display with a Trigger cube sump. Total water is estimated at around 80 gallons give or take. Reactor is an Aquatop 25 I think... 95gph pump.

Coastie Reefer · Jan 3, 2020

That's not a huge problem if your corals are doing fine. I don't really like GFO, so if I ever need to reduce P04 I use something like Brightwell Phosphate E...

IF you want to use GFO I'd suggest using 1/3 of the recommended does for you water volume. Run it for a few days to a week and continue to test till you get your P04 to where you want them to be.

Billldg · Jan 3, 2020

.3 ppm P04 is a little high, but if your corals aren't showing any problems, then I wouldn't worry about it to much. GFO is a very powerful tool and does it job to good, IMO. So much so that I see far more problems with people using it than not. That is not to say it's bad, just very powerful. If you must use it then I agree with the above and start off with a 1/3 of the recommended dose as it can quickly strip your water of P04, and then it is hard to get it back.

lapin · Jan 3, 2020

1 cup
If you got rid of algae you got rid of a consumer.

SashimiTurtle · Jan 3, 2020

Recommended dose is 1TBSP per 8 gallons. 80g estimated water volume would mean 10TBSP of GFO... imma try 2, maybe 1.

lapin · Jan 3, 2020

Robin Haselden said:
Recommended dose is 1TBSP per 8 gallons. 80g estimated water volume would mean 10TBSP of GFO... imma try 2, maybe 1.

All GFO is not created equal

SashimiTurtle · Jan 3, 2020

Coastie Reefer said:
That's not a huge problem if your corals are doing fine. I don't really like GFO, so if I ever need to reduce P04 I use something like Brightwell Phosphate E...

IF you want to use GFO I'd suggest using 1/3 of the recommended does for you water volume. Run it for a few days to a week and continue to test till you get your P04 to where you want them to be.

I tend to like Brightwell's products. I use their salt, Microbacter7 and have some of the 1.5" cubes in my nano. I'll look into their phosphate media. For now, I have GFO on hand.