dirt stains on stairs

[Kevink]

This is my second year with the pool but now I have stains on the stairs which I didn't have previously (see dark areas of stairs). The stains are brownish and they do not respond to ascorbic acid. They don't come off with a stainless steel brush either, but a pumice stone works (if you look at the upper right corner of the stairs you can see lines from using the pumice stone). The problem using a pumice stone is that I have 3 stairs and they're wide!

If someone could help me determine the cause of the stains and suggest a relatively quick way to get rid of them I would appreciate it! The pool is open year-round. I get quite a bit of dust on the stairs and have to brush them every couple of days. Also, I inherited a high calcium level (originally over 600) which I'm working on and have brought down a bit. Here are my latest test results:

FC 5
PH 7.5
TA 50
CH 550
CYA 60


Should I shock for a few days? Haven't done that in a while.

Thanks

 

[duraleigh]

Your CH is the likely culprit and it will be tough to get off. If you can drain the pool to expose at least SOME of the steps, you could use a solution of muriatic and water to remove them rather easily.

 

[257WbyMag]

That looks like calcium scaling to me.

 

[Kevink]

Thanks for the responses.

I did a partial drain last year (about 45%) and was able to bring down the CH to 500 (it was originally at about 750-800). There's definitely scaling in other parts of the pool, but the stairs are the only places where the stains are brownish. Looks like I have to do another drain this year.