Red Film/Covering on Live Rocks

I started my tank about 10 months ago. I have a 90 gal. tank with a 50 gal. below for my refugium. I have a skimmer in the tank below and very good light.
I have a mixture of corels and about 12 fish.
About a week or 10 days ago I've notice this darkish red film/slime/coating on a few live rocks. Within the past week it has gotten worsee.
Can anyone help or tell me what it is?

 

Cyano, increase flow, oxygen level, and maybe your magnesium. i found that by raising mine, my cyano started to go away and didnt come back. but do check so you dont add too much.

 

I agree Cyano. I had this problem also. i thing everyone gets it at some time. I had a high Oxygen level so I bought another Hydor pump and waited. They say that Cyano hates high flow but mine just started growing in others areas along with the spot it already was. So maybe raising your Magnesium will help. And as much as I hate to just add a " Quick Fix " to my tank I finally broke down and got some Red Slime Remover made by ChemiClean. And I have not seen it again. Also It did not hurt anything in my tank. So its really your call.

 

Same here, added another powerhead to my nano and it solved the problem....

 

Can you test for magnesium?

 

If Cyano is that dark redish velvet looking thing that covers LR, call me crazy, but I love that stuff. It adds color and depth to the tank. Dont get me wrong, I dont have ALL over, but I do have it in some places.

 

I had it on my sand bed at first and my SS star wanted nothing to do with it or did any of my other cleaning helpers. It looks really bad on the sand bed but not so bad on the rock. The problem is if you dont get it under control it will start going everywhere. But I still agree with Aquaboy. Check your Magnesium and if you can your oxygen levels. But watch the powerheads as you may just move it from one spot to another. With a newer tank I would try adding a powerhead. But with your tank It most likely is not a flow problem. Most likely you are missing a element in the system and the Cyano growth is making up for the loss. Most of the time it is from lack of good bacteria. Also what type of lighting do you have?

 

Yes. Salifert Magnesium Test 30ppm 50 tests: Premium Aquatics

Just an example.

 

Yep cyno.

Every tank gets as maturing one time or another. Had couple of outbreaks early on, but have never seen since.

Vacuuming up as much as I could and doing some back to back water changes took care of mine. :-/

 

O.K. folks, thank you for all the suggestions and help. I did ad Red Slime today - turned off my skimmer. Tomorrow I will change some water. I have to pick up a Magnizium test kit. I have 3 powerheads in the tank now, but can ad a fourth. Some of the stuff is also on the sand. I have tried to syphone some of it out with a turkey baster and a air tub.
Every morning I come out to look my tank over before going to work. I'm amazed at all the live things and how the coral (kind of) go to sleep.
Thank you again. I will keep you posted, as well as a Magnesium reading.