ID please

[sammyw]

Can someone id this weird green spot? It has been there for about one month. It doesn't appear to be slime, but I've never had slime to compare it to. I'll get parameters posted in a little while. Just did a water change, but typically, my water is excellent! I use ro/di and change about 10 gallons per week. It is a 50g with about 50lbs lr, 2)250 MH's. Lights are on for 8 hours per day. The tank has been up and running for about 3 months.

 

[it's_fishy]

Really hard to tell from the pic but it could be coralline...somehow i doubt it (just my instinct), but the bottom line is if it doesn't bother your ecosystem....just sit back and enjoy. If it's presence in the tank disturbs you or you other inhabitants then seek to remove it.

 

[mcbdz]

It looks like green slim to me. At you next water change try to syphon it and see if it comes out. If not it could be hair algea.

 

[fishkiller]

cyanobacteria... green is just one of it's suits. Make sure the cartridges in your RO/DI don't need replacing, any of em. Maybe try a little chem filtration if it doesn't subside.