how much copper is too much copper?

[dody]

the reason i ask this question, is because last year, we had a pool store experience (and ended up with quite a bit of copper stains) got that cleared up, but this year, the stains are coming back. (so maybe we didn't get it cleared up like we thought we did!) i did the metal stain protocol, and cleared the stains, but now they're coming back again. we use bleach, borax, the very occasional triclor puck (only 2 so far this year). i've got polyquat, and metal out, and use them sparingly. I'm of the understanding that none of the above contain copper. And yet the stains have returned. I'm all set to go with another stain removal session, but I'm wondering if i'm missing something else.

to that end, I checked our town's water quality report, and it says

Copper***
0.19 ppm at the 90th percentile

I don't know anything about this, so I have no idea if that's high or low, if i'm not using the sequesterant/metal out on enough of a regular basis to prevent the stains (every other week), or if I'm inadvertently adding it somehow.

My #'s are as follows:

C- 5
CC- 0
FC- 5
TA- 100
PH- 7.8
CH- 300
CYA- 50

Any thoughts?

 

[JVTrain]

Copper concentrations and how much is bad for the pool, that might lead to staining and/or green pool water depends on pH and FC levels, but in general, less than 0.5 ppm copper will likely not have much effect on pool water. 0.3 ppm is even safer. Over 0.5 ppm you may have some staining or water discoloration, depending on pH.

 

[pooldv]

Keep in mind that copper tests only test for copper in the water. So, any copper in stains or that is sequestered will not show up on the test.

 

[JoyfulNoise]

Your copper stain treatment did not remove the copper from your water, it only removed the solid copper stain from the wall by making it dissolve back into solution. So you still have copper in your water.

You need to find a pool store that can do a "total copper" test, not just a "free copper" test. Free copper is just the amount of copper ions in solution but does not typically include copper that is sequestered by a metal sequestrant chemical. Total copper uses an acid digestion step which frees up all the copper in solutions and gives you a total amount.

The only way to get rid of the copper is to replace the water. You must empty some volume of pool water and replace it with metal free water.

 

[dody]

hey thanks! sorry it took so long for me to respond, we had a wicked storm come through about noon. 75+ mph straight line winds, so, i've been working on getting half a tree out of my pool. and the dirt! oy! the pool's going to be cloudy for days just from the dirt.

i'll see if one of my pool stores can do a "total copper test", once we get the clean up finished.