Trying to kick cyano out of my tank!

(edit: figured out it was cyano. New questions on post#5)

Hello! Ever since my tank finished cycling about 8 weeks ago, my white sand bed has been anything but! I think the first outbreak was diatoms pictured here which I know is normal



Ever since then I've had this blackish slimy algae pretty much covering my sand bed. Is it cyano? I sift my fingers through it lightly about once a week, but this stuff is ugly and I'm not sure what it is







I've been using RO/DI water from the start. Flow is 3000gph in a 75g, with 3 powerheads and the return pump.

I installed a GFO reactor yesterday - hoping this will help? Should I siphon out what I can get, or just continue to leave it be and hope it runs its course?

 

It's cyano and almost eveyrone has dealt with it. If you do a search of this forum you will see numerous posts on how to combat it. GFO is a good start. Basically you need to lower phosphates, siphon out what you can and shut out the lights for two or three days.

 

Thanks I will do that! I'm glad to know what it is at least. After some reading I also fear I may have been overfeeding. We have those frozen cubes (Emerald Entree and Brine shrimp) and I've been cutting the squares in half and feeding pretty much every day, switching between the two.

(two clowns, cleaner shrimp, electric blue hermit crab, dragonet)




I'll cut it down to 2 very small feedings every other day. Should I get some pellets or flake, and maybe feed that once a week and cubes twice a week?

 

at 3k gph you have good water turn over, but how do you have the power heads oriented? What type of filtration are you using? I have lower turnover in my 75 and dont have any, but im running a skimmer/ats.

in my 29 mantis tank I get small spots here and there but its mostly related to the water flow & areas where current isnt hitting. I started my power heads on a on/off schedule and have all but erased it.

 

Yeah I got a skimmer in the sump. I think my problem is over feeding and some food settling on the sand. I've got new bulbs incase that was the problem, and am lowering phosphates with GFO. I should have enough flow, but could I position my powerheads differently? Here is how it is:

I've got two power heads facing each other with the return line in the middle of them, the lower one on the left is a 600, I've got a 1400 and 750 on either side. Like this:




If I turn off the lights for three days will my corals be okay? Just a couple zoas, mushrooms, one pipe organ and one kenya tree.

 

bump. new question. do you guys think I should position my powerheads differently?

 

It looks like you should have pretty good flow to all parts of the tank with the way they are configured now. I have the same corals as you, except the pipe organ and mine were all fine after three days without lights. Here is what worked for me:
Day 1: Turn off the lights, cover the tank with a blanket, siphon out all cyano that you can and do a 10% water change.
Day 2: Leave the lights off, leave the blanket on the tank, siphon any remaining cyano and do another 10% water change.
Day 3: Leave the lights out and blanket on.
I also reduced feeding and redirected power heads to cover more of the tank. It may not take three days for you but it worked for me and my corals were fine.

 

thanks, come to think of it I doubt it can be lack of flow causing it since it's pretty much covering my entire sand bed, not just one part. I bet it's from over feeding. Because I pretty much have every other cause covered.

Flow - 40x turnover
Water - RO/DI from the start
Salt - Tropic Marin (isn't supposed to be high in NO3 or phosphates etc)
Lighting - new bulbs
Running Skimmer
Running GFO
15% water change bi-weekly

And it's not really on the rocks. The one small rock that had it used to be on the sand bed until I moved it higher. Theres none left on it anymore.

I'll probably siphon what I can out (Im worried about sucking out too much sand though) and kill the lights for a couple days. And feed less in the future of course.

If theres anymore suggestions let me know - I may be over looking something else