Too much GFO???

[rickh]

I recently switched from Phosban to Bulk Reef Supply GFO. The hair algae is vanishing, but some of my Zoas look funny. They don't open and look like they have Zoa Pox. Has anyone else experienced GFO bothering Zoas or do I just have the Pox??

[Toddrtrex]

I haven't, but I know that if you use too much GFO too soon, that can lower your Alk, not sure how much that would effect zoas, but would be something to test for.

[DJBoy98]

Can you explain further about GFO relationship with ALK?

[noboddi]

Photosynthetic cnidarians need at least some PO4 in the water for the health of their zooxanthellae (which is algae after all). If you go too low they may be affected. I have seen this with acro, but don't have a lot of experience with zoas, so it could be a possibility

[rickh]

Thanks for the info. I will remove some or all the GFO tonight.
R

[james3370]

give the guys at bulk reef supply a call....they are very nice & have great customer support. they should be able to give you some excellent advice

[Pohono]

On the bags of GFO I get from Bulk Reef Supply, it states on the instructions to run half the dosage of GFO for 4 to 8 weeks....I went with 4 ;) Basically any drastic change in your water, even if the change is for the 'better' will cause a bad reaction in some of your stock.....suddenly using lots of carbon will create drastically more light, which is 'good' but stuff has to have time to adjust.....noticing your calcium is down to 50 ppm and dumping in a gallon of 2 part to get it 'right' in one day will also cause problems. Just take it slow.....use the half dosage that BRS recommends, which should prevent further algae growth, and will allow some 'getting used to new water parameters' time for your stock, prior to attempting the mythical 0 phosphate tank. Good luck.