What to use to remove copper staining on drained pool.

[judysimonson]

Hi,

I'm new to this site and hope to get some help.

I have a small (7,500) gallon indoor pool (plaster I assume, it looks like plaster) I just got through draining the pool because the water was getting too hard. I top my pool off with my well water that is pretty hard. Over time the water gets too hard and my understanding is the only solution is to drain and add new water.

I have some copper staining left over from the last time the water got too hard and ate through several copper pipes. My pool guy at the time did some kind of acid wash but wasn't able to get all the stains out. He replaced the copper pipes with pvc before we refilled the pool.

I would like to see if I could get the copper stain off the pool before refilling and am looking for a process that I can do myself.(previous pool guy no longer around so I am the new pool lady)

Any suggestions on what I can use (muriatic acid or something from Jack's Magic)? Is acid wash hard on a plaster pool? Also, any ideas on how to avoid the hard water situation in the first place. Would a whole house water softening system do the trick? I do use algaecide with copper which is recommended for well water. Could that be adding to the copper staining problem? I don't add very much because I don't have that big of an algae problem with the pool being indoors.

Thank you for any advice you can give me!

 

[chem geek]

Welcome to TFP!

Hard water does not eat through copper piping. It's more likely to be low pH that damaged copper piping. By any chance were you using Trichlor pucks as your source of chlorine and not paying attention to the pH or did you place such pucks in your skimmer?

Copper staining is difficult to remove from plaster, but the Jack's Magic products are probably your best bet for such removal.

You say you use an "algaecide with copper" so that is more likely the source of your copper staining. You should not use algaecides at all but most certainly not ones with copper in them. Maintaining the proper chlorine level (see the Pool School Chlorine / CYA Chart) relative to the Cyanuric Acid (CYA) level is all you should need to prevent algae growth.

If you've been using Trichlor pucks, I suggest you read through Pool School to become more familiar with how to maintain your pool primarily with chlorinating liquid or bleach (with CYA added separately). For an indoor pool not exposed to sunlight, the CYA level can be lower but should still be at least 20-30 ppm. Then follow the chart and keep at least 2 ppm FC in the pool at all times.