Help identifying stains/scales

[foolboy2]

Hello,

New to registering, but these forums have been invaluable in getting our new pool chemistry under control.

We bought a house with a pool and we have this stain throughout. I was hoping someone could help identify this and suggest some ways to fix it.



Any help would be greatly appreciated!

 

[smforte]

If you can temporarily place a chlorine tab on the stain and it lightens, it's organic or place ground up vitamin C in a sock and rub it on the stain. If it lightens it's metals. What test kit are you using? Post some test results and someone will be along to help you.

 

[pooldv]

Please add your pool info to your signature so that we can better help you, more here, Pool School - Read This Before You Post

 

[foolboy2]

@pooldv Thanks! Signature updated, will get pump info later this evening.
@smforte: Chlorine puck did nothing. Vitamin C did lighten it. See below for test results:

FC	10
TC	10
pH	7.4
TA	110
CH	300
CYA	60

 

[pooldv]

Ok, if vit C lightens it then it is metals. Either copper or iron.

Are you on a well? Or city water?
Do you add algaecide? That adds copper.
Use a mineral system with copper ionization magic? That adds copper.
Have a heater with a copper heat exchanger and low PH, below 7.0, for a while? That adds copper.

Have your read this? Pool School - Metals in the Water and Metal Stains

You can order this, Jacks Magic Stain Identification Kit JMSTAINID at Sunplay

Or you can try this, Ascorbic Treatment to rid Pool of metal stains

 

[smforte]

Pooldv has you covered! I should be a pro at AA treatments. I've done enough of them. Trick is afterwards keeping ph on the lower side, FC no higher than your target (any higher will release the metals back into the water) and plenty of sequestrant weekly. I use Jacks Magic.

 

[YippeeSkippy]

...and you also need a test kit that tests for CCs along with FC. Do you have that? You didn't mention, and the Taylor K-2005 does not.

 

[foolboy2]

Awesome, thanks guys. I just ordered the Jack's Magic kit to see what it is. Should be interesting.

Regarding the test kit. I thought the combined chlorine was just the difference between the total and free, yielding that chlorine that was currently tied up as chloramines. Is there a specific test for the chloramines or does the TF-100 and K 2006 simply have better resolution to determine the probably small concentration? If it is the ladder, would the suggestions listed on this thread (Updating Taylor K-2005 to K-2006) suffice?

 

[YippeeSkippy]

The Taylor K-2005 only tests chlorine up to 10ppm and that's only via a color matching tube, right? That's not how the FAS-DPD test works hence this is why its the one we trust.
If you need to SLAM you need more than 10ppm and you need to be able to monitor the combined chloramines accurately.

You can order the FAS-DPD test alone via TFTestkts.net

 

[foolboy2]

Yeah, it has a color chart up to 10, however, I've been diluting the pool water (50:50) with distilled water and doubling the resulting values when I expect the values to be above 10 PPM, or when they hit 10. I do like the titration till color change aspect of the FAS-DPD compared to the color matching, that can get annoying. Thanks for the advice! Next on the list.

 

[pooldv]

It kind of looks like iron. If it is iron and you ever do precipitate the iron into the water and turn it brown grab some polyfill material and stuff it in the skimmer basket and it will filter out a bunch of the iron from the water.