Blue stain on sides on in-ground pool

[labbatsbrew]

I'm not too savvy on posting pictures but if this thread needs it I'll do my best later.

I've had this home for two years and it has been blessed with a trouble free pool for the last 12-16 months. Water was always clear and levels were acceptable. Then we started seeing a dark blue algae looking infestation on the walls of our pool where there isn't much sunlight hitting it. I can scrape off a bit with my finger, but it's very thin. For all I know it's a stain.

Today I got an algae brush and put some muscle into scraping the sides of the pool with it where this blue algae or stain is. Nothing changed. I'm unsure what it is or where to go from here. Would draining the pool and acid washing the sides fix this?

Thanks in advance.

 

[jblizzle]

Welcome to TFP!!!

Did the substance feel slimy between your fingers?

I think pictures are going to help in this case. Here is one method:
how-to-add-pictures-to-a-post-full-guide-with-screenshots-t45050.html

 

[labbatsbrew]

It isn't slimy so it must be some kind of stain.

 

[jblizzle]

I can not see the picture, could be my firewall, but looking at the text of your post, I do not think you linked to the correct URL.

 

[labbatsbrew]

I didn't. Working on it.

 

[labbatsbrew]

Got it!

 

[labbatsbrew]

Here's another. Hope this helps.

 

[duraleigh]

Could you post a complete set of test results, importantly including a test for copper?

 

[Melt In The Sun]

To expand a little on Dave's request...do you use a copper-based algicide in the pool? At first glance it looks very much like a copper stain.

 

[Richard320]

I suspect it's some scale that has been dyed with copper compounds. Betcha the pH is high.

 

[SebringDon]

Two years and 12-16 months clean with a current onset of algae (if that's what it is) raises the CYA flag in my mind. Have you been using tablets to chlorinate? Have you read through Pool School? (Link on the upper-right of every page)

 

[onBalance]

I think there are two problems. Yes, blue/black copper (oxide) staining, and also "black algae" spots.

 

[labbatsbrew]

I think you all are spot on. Thank you for the ideas. I'm pretty sure it's copper related and will try using some chemicals for that and reply back on my results.

 

[dmanb2b]

hold a vitamin c tab against the stain...if it lifts it's metal. I agree with on balance as well...almost looks like black algae too.

 

[labbatsbrew]

Draining and acid washing today. Will post pictures again later this week. Thanks again to you all for the help.

 

[Richard320]

Draining and acid washing today. Will post pictures again later this week. Thanks again to you all for the help.

We never did see any test results....

It's pretty important to figure out exactly what it is, so steps can be taken to prevent it from happening again.

 

[jblizzle]

I agree ... seems like a sudden drastic step ... or you got advice from somewhere else and we do not have full information.

Would hate for you to spend the time, effort, and money only for stains to reappear.

 

[labbatsbrew]

I had planned to acid wash my pool this November for a while now. Gotta say it was a lot of work but I'm glad I did it myself. Saved a ton of money.

Stains are still showing even after scrubbing the heck out of them but I bought some product for copper stains and will keep you all advised. I don't own a test kit and frankly I've been putting off taking the water sample in for analysis at Leslie pool due to it being a moot point until after I drained and acid washed the pool.

Took the advice of this site and invested in several chemicals and the Taylor K2006 test kit from Amazon.com. Looking forward to using them. I've just had enough of pool guys and finally let the guy go. Some friends recommended this site and I've been anxious to get started. I'll be sure and post water results when I get the Taylor kit.

 

[jblizzle]

Sounds like you are making some good decisions by taking control and getting a test kit. We are here to help if you need questions answered

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[labbatsbrew]

Got the test kit today. The blue stains on the walls are getting less but are still 2/3 there. Probably will take some time to fix.

Here's the test results...

Ph- 7.7
TA- 120ppm
FC- 0.6ppm
CC- 0.2ppm
Calcium Hardness- 290ppm
CYA- 0

Obviously I need to buy more CYA. I used the chlorine tabs with CYA in them from Leslie's Pool but it doesn't seem to be enough. Is the SwimTime brand stabilizer from WalMart any good? I may need to make a run there.

Thank you