Algae ring in skimmers

[Drayden21]

Hello everyone
I have been having a problem with a predominately black with a little bit of green build up around the inside of my skimmers. Assuming this is algae. I don't have it anywhere else except a little bit on the rail of my auto cover. Pool water is clear. Balancing is good except this year my free chlorine has been tough to keep consistent. I've used a lot of tablets. I have been using a sponge to clean my skimmers but I'm getting tired of doing it everyday. Does anyone know what,where why and how I can solve this problem.
both skimmers get it & one is worse than the other

20000 gal
Plaster
D.E.
5 year old pool

 

[duraleigh]

If you have algae, your chlorine level is too low or has been too low in the past.. It really is that simple.

Posting a complete set of test results will be helpful to try to get you more precise information.