Recently I got desperate and started removing live rock that i was convinced was continually leaching phosphates into the tank. I am going to be a lot more selective of the live rock I put into my tank next time, for sure.
in my case, i was new into this hobby and overfed like crazy for a 4-5 month period. I think the rock absorbed my excess nutrients and then once I got the equation fixed, started leaking them back out causing algae growth.
For the original poster....wow, you have cotton candy algae growing IN YOUR GFO container? LOL that's insane. even my strain of CCA was not this bold.
I hesitate to suggest this (because it didn't work for me) but some reefers swear by using Extra Large Mexican Turbo's to eat up the CCA. Maybe once you get a handle on your nutrient situation, you could add one or two to help you clean up the rest.
Pictures please!
I'm starting to be convinced you can have high nutrients without phosphate/nitrate.. My phosphate read .00 using a Hanna photometer and nitrates were undetectable using API after a week of running Phoslock, yet I had some patches of Cyano in low flow areas and flatworms were thriving. Been using Zeovit for a few weeks now, cyano is gone and flatworms dying out, yet phosphate still reads .00 as well as nitrate.. There has to be some component amongst "nutrients" that one can't test for and doesn't necessarily correlate to nitrate and phosphate levels.
I've been thinking about this situation a lot today and I have some thoughts. First, this has got to be a case of high nutrients. If it was low nutrients then the algae couldn't grow and it would be dying off. The fact that you cannot read a level of the nutrients in the water means that they are being absorbed by the algae quickly, hence the rapid algae growth. The paling and browning corals corresponds to this as an indicator of poor water quality and phosphates. But since you are running GFO and other chemical media the rapidity of the algal growth is somewhat interesting and puzzling.
The first step has got to be reduced feedings and checking the water sources for phosphate contamination.
I hope this stuff can help!
is that filter sock being used? because I see a flex pipe in front of it.
you can clean your sump, remove all the red stuff, rinse the chaeto, maybe take out the LR rubbles and rinse them in tank water to remove any algae and detritus. I can't see all your fish, but it looks like half a cube every other day is enough.
I don't see a skimmer, if you don't have one, maybe consider using a skimmer in that middle section.