Aquarium problems

[Billycaicedo]

I am relatively new to the saltwater world. I got a 90 gallon tank a couple of years ago. It had quite a bit of live rock, a few corals, and some fish. I set it up and got some pretty good growth initially. The last several months, I have noticed that my live rock is looking bad and there is something growing over some of the coral. I am posting some pictures for critique and ideas. ANy helpful tips would be greatly appreciated.

 

[Lovemyreef2015]

I see what looks like red cyanobacteria and some aiptasia pest anenome. Can you post your parameters and what type of lighting you are using?

 

[Zack K]

If it is the red stuff you are talking about, it looks to be cyano Bacteria. Their are multiple threads in how to treat this but I found that a product called chemiclean. Tank looks excellent otherwise!

 

[Billycaicedo]

I have a 4 foot LED and a fixture with 2 65 Watt 10,000 K bulbs and 2 Actinic bulbs in it. No nitrate, nitrite, or ammonia, pH is 8.2-8.4 range, Specific gravity 1.024, and salinity is 34. I have 2 power heads and a Gyre. In the sump I have an ASM skimmer, large UV sterilizer, and an auto top off hooked to a 6 stage RO/DI unit.

 

[Billycaicedo]

I was concerned about the purple carpet-like stuff that has covered one of the corals and wiped off the grass-like coral that used to completely cover the rocks

 

[Mikedawg]

I was concerned about the purple carpet-like stuff that has covered one of the corals and wiped off the grass-like coral that used to completely cover the rocks

I would syphon cyano up with next water change and make sure the areas where it is growing have good water flow before I consider using chemicals. Cyano is very common and its growth is often spurred by excess nutrients in low flow areas. Here's a pretty good video:

 

[Mark Waltermire]

In term of parameters can you post what are your alkalinity, calcium, phosphate, and magnesium. I have a feeling that the red cyano might be a result of having high phosphates, but won't know without testing. The corals initially might have been growing well but used up all of your alkalinity and calcium. Do you dose anything in the tank? What is your water change schedule and what type of salt are you using?

Do you run GFO and/or Carbon?