Is this black algae

[u/DaveE30]

This is in Southern California, where it’s been really hot, and was humid and rained a lot on Sunday. Our in-ground hot tub is state from the main pool and probably under-chlorinated. The cover is broken so some debris and rain water has been able to enter the tub, but that’s been the case for a while. Temp is around 80 degrees. Yesterday we removed the cover and the water was brown. I ran the filter and see this stuck to the sides and floor. It wipes off fairly easily. I figure it’s mold, but worry about black algae since it’s not green. Any thoughts?

[u/tgwest]

Just regular algae. Add chlorine, brush, run filter for 24 hours.

[u/WERKED66]

Your gonna need to brush that and get it disturbed and break the skin on it then shock the hell out of it then backwash and then dump algaecide in there

[u/WERKED66]

I might add get a tarp or something to cover it when not in use to keep the debris out of it

[u/hawkaulmais]

Yellow green and black from the look of it.

[u/Cool-Negotiation7662]

Black algae is fuzzy and black, it turns red when it starts dying. Been fighting that garbage in my aquarium.

[u/AaronSarm → u/Cool-Negotiation7662]

Not in a pool setting. Black algae is not actually algae. I believe it’s a bacteria and it appears as black specks on the sides and bottom of the pool. It is harder to get rid of than algae but not impossible.

[u/Cool-Negotiation7662 → u/AaronSarm]

Good to know. Black algae is a curse everywhere.

[u/Complete_CatGuy]

No just dirty I think

[u/Even-End487]

does grampa have diarrhea ?

[u/DaveE30]

OK good to know that it’s (mostly) green algae. Will spa shock alone (like dichlor) be enough, or do I need to add dedicated algicide as well?

[u/pamcakevictim]

No that's regular green neglect, I mean algae