gfo in a 5 gallon nano reef

[BeachVacationer]

I have a fluval spec V with upgraded pump and led lights. It's been running for over a year. I have soft and lps corals in it with 2 stunted clown fish in it. My clean up crew consists of 4 astria snails, 1 skunk shrimp and a small zebra snail. The snails do a great job at eating algae, in fact I don't have an algae issue at all in the on the live rock or the substrate. What I notice is a reddish growth on the glass within a week's time. It comes off easily with a plastic scrubbie but if I let it go for 2 weeks I need to use a razor blade to remove it from the glass.

I'm wondering if I should try using GFO to lower my phosphate to see if lower phosphate will reduce this growth on the glass. But I've heard GFO should be used cautiously.

Why is there an issue with the use of GFO? Is a sudden reduction in phosphate a bad thing or does GFO release something harmful to corals? Just curious before I use it.

Thanks!

 

[NeilFox]

Doubt you would need it. What are you using for your makeup water? Sounds more like diatoms.

 

[BeachVacationer]

I use RO water for WCs and top off. I'll measure phosphate tonight.