Black mold

[Roscoe]

I have been fighting with the pop ups. I now have all of the hardware and everything it back functioning. While working on this there were areas that weren't being cleaned well, now I have black mold spot areas where the dirt was.

The current reading is:
FC 2
CC 2
pH 7.5
TA 97
CH 280
CYA 70

I read that my CYA is too high. I intend to drop the pool level a couple of feet then refill. I assume I should also stop using the 3 inch tablets and move to liquid chlorine. Shock it. And then spend my free time scrubbing the pool with a metal brush.

Any other advice would be appreciated.

 

[Msch99]

Assuming you are using either the TF100 or Taylor K2006C test kit. If not, add enough liquid chlorine to maintain 5ppm FC and order a good kit.
Yes, stop using pucks and switch to liquid chlorine.
Your FC is way too low for your CYA. See Chlorine/CYA chart

If you have one of the good kits:
I would lower PH a bit to 7.2. Yes, with muriatic acid.
If you are going to exchange water to lower CYA it would be a quicker slam and use less chlorine.
Follow Slam procedure after exchange and checking your new CYA level.

 

[Roscoe]

Thanks. Pool store reading. Moving to liquid will force me to buy a "real" tester.

 

[Msch99]

You need one either way. Yes it costs $75 or so. But way cheaper than guessing and throwing in stuff that you may or may not need.
Impossible to know what level to maintain FC if you don’t know for sure what the CYA is. Too little FC and you have algae. Too much FC and it is too harsh.

 

[Roscoe]

Since I am reducing the pool level now, does it make sense to pour on some bleach (bleach and water mix?) on the exposed steps that have black mode spots, before I refill?

 

[Msch99]

Scrubbing with a stronger solution and a brush would help. I have vinyl, not sure how strong to mix for yours.

 

[Roscoe]

Was thinking the same thing. Will do it about 30 minutes before the water will start to cover the step. Thanks.