Algae or Cyanobacteria or both?

[Kristine]

Can someone tell me what's going on on my rocks? I'm new to the hobby and my tank is only two months old. I have 8 Blue Legged Hermit Crabs and 3 Blue Green Chromis'. All my Chemistry levels are where they are supposed to be. I'm thinking I need to reduce my lighting time.
Kris

 

[DOI]

The brown appears to be cyano. If it is easily siphoned off its cyano. The green could be cyano as well since it does take on various color forms. Try to blast it off with a turkey baster and suck it up. If it holds on well then it's most likely algae. Cyano is photosynthetic and chemosynthetic. Shorten your light time for awhile to knock it back. If you can, try to increase the flow in that area so it won't be apt to settle there again.

 

[Loki]

Cyano. Well the red/dark colored one is. It may be a good idea to up the amount of flow in your tank and reduce the amount of waste going in. Smaller feedings and more water changes. I am currently running 3 days without lights to try to get rid of my cyano.

 

[Chameleon]

The one that isnt red could be diatoms...they appear in new tank sometimes but usually go away if good water parameters are maintained

 

[REEFKEEPER10]

How long has the tank been running and what do you have as far as flow. Lighting may not be the problem but a few days of darkness might help some.

 

[Kristine]

My tank was started on March 19. The spots started to show on April 29. I did a fishless cycle and they fish were added the day the spots started to show so I don't think the problem was waste related. I have my flow as high as I can get it without the flushing effect. So it leaves me to believe it is light related. the spots are all at the top sections of the rocks. It does not come off easily. I have tried getting it off by scrubbing with a new toothbrush and the top layer came off but the lower layer didn't.

 

[Loki]

Do you have any powerheads? It sounds like you have a sump with a return pump. Is that correct? What size tank do you have?

 

[Loki]

Oh and how long are your lights on each day. It may be a good idea to cut them back. When I first started my tank I had the lights on for 4 hours a day. I am up to 7 now. I wouldn't go more than 8 hours per day.

 

[Kristine]

12 hours. I will cut back. This weekend I wont turn them on and then go to 8 hours and see what happens. I have my name on the email list for a CUC from LiveAquaria.com too. Thank you everyone for your help. I really appreciate it.