Metal Staining due to Heat Pump Heat Exchanger? Copper Testing Questions

panamax53

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Dec 10, 2015
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Doral, FL
I bought a LoMotte Test Kit w strips for Iron and Copper. Iron was 0, but the copper strip changed, but almost indiscernibly. What level of ppm Copper measurement do I need to look for in a test kit? Are the LaMotte strips adequate?
I suspect my metal staining came from my Jandy Heat Pump now 6 years old. I have done the Vitamin C test and it reacts with the stains in my pool. It does not remove them but causes some fading after creating a cloudy appearing area which disappears after a day. I used a La Motte test strip and it changed ever so slightly, but did change to somewhere between 0 and 0.3, closer to 0. I would like to measure the exact level or is that really necessary? Is that reading something to be concerned about? The reading is relatively low on the scale, but is that because the heat pump is currently not running.? At what level does one need to be concerned about copper?
I am going to attempt to use Sea Klear's citric acid based "Metal Stain Remover" in the next few months. after the weather cools down to the 70s and the algae threat is lower. One of the requirements is lowering FC to 1 and pH to 7.4. I do not have high hopes for it, but will give it a go. In the meantime Sea Kear's "Metal Klear" will be used to at least stop further staining.
I wish someone had advised me to use a metal sequestrant such as Metal Klear from the beginning.

No, the stains are not algae. They do not brush off. The pool has been well cared for via TFP principles. I've only needed to Slam 3 or 4 times in it's 6 year history!! Thank you TFP.

I heard Jandy's heat exchangers were possible culprits of this and that Jandy changed their metallurgy about 5 years ago. Hmmmmm. I wonder if it is possible to install a newer heat exchanger that doesn't leach metals?

Anyone else have similar appearing SWCG pool with a Jandy Heat Pump?

I do have a bypass valve and one of those red flapper valves with the clear acrylic top. I never close it off during the summer season. I did not want to have stagnant water in there or was that wrong? We run the pump 15 hours a day to keep the pool clean. I do close off two shear valves because when they are open the flow rate is too low for the heat pump and SWCG to run when the pump is on its low speed cycle.
 

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For iron and copper, we generally become concerned when the level is 0.3 or above. That's when we start to see more reaction of metals to chlorine. Sometimes careful management of the FC and pH help to prevent that interaction, but it's not an exact science. Test strips are never accurate, but really good metals test kits simply aren't feasible for a residential owner. But the recommendation is almost always the same - replace the water if you can, or at least a good part of it, to lower the content of metals. That way you don't have to rely on sequestrants over & over.

 
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