Strange Slime Algae Help

[AquaScapes1]

Hi, Can anyone help me identify and possible kill this algae.This is a tank I recently took over taking care of. It was in Very bad shape but after 5 good size water changes and vacuuming it seems to be getting a little better. But I can not get rid of this algae(and or bacteria?)It lives in the sand bed and under rocks it seems to be a green slime, but I have never seen anything like this. It makes the sand clump together like mud and the stuff under the rocks is very slimy to the touch.
All water parameters are at zero or with in tolerant range. I have tried two does of Chemi clean and it is not helping much. Skimmer is a reef octopus which is always pulling out nasty liquid. Skimmer was not running until I took it over
125 gallon with 5 power heads and wave system so stagnant water is not the cause.
There is a UV
Help and thanks

 

[moondoggy4]

I would start dosing Dr Tims Waste Away it may take a couple of bottles, is this stuff growing on the glass or inside the return tubing as well?

 

[karimwassef]

Sounds bacterial or protozoan

Can try chemiclean too

 

[AquaScapes1]

I would start dosing Dr Tims Waste Away it may take a couple of bottles, is this stuff growing on the glass or inside the return tubing as well?

Thanks, I will give it a try.