Pool Chemistry is a mess - need advice on where to start..


Nov 25, 2017
Just got my pool water tested and seems I've got some big problems... Need some advice on what to do first, second, third.. etc..
Here's the numbers for my 15K Gal Fiberglass pool

Free Chlorine - .11
Total Chlorine - .11
Ph 6.3
Total Alk - 0
Calcium Hardness - 141
CYA - 158
Iron - .1
Copper - 3.6 (yes, this is correct)
Phosphates - 112
TDS - 2600

I think the high copper might have come from my heater, were the coils had eroded. This has been replaced. So, should I start with raising ALK? Lowering Copper? Lowering CYA? Prefer not to drain if possible.. Live in Southern Cal where cost of water is crazy..


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
With that much copper, do you have staining? If that level is correct, you should fully drain and refill. If TA is 0, your pH is more like 4.5 or so. Now would be a great time to drain/exchange the full volume.

Otherwise, we do not provide guidance based on pool store tests. You need your own proper test kit. I suggest the TF-100 A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
When I see those test results, I see two things
1) Pool store testing
2) A steady diet of trichlor pucks.

I'm willing to bet your CYA is much higher than the 158 reported. Trichlor leaves 6 CYA behind for every 10 FC it adds and it's also very acidic. The FC goes away. The CYA stays and builds. And the pH and TA drop lower and lower and lower. If you managed to dissolve your heater, imagine what it must be doing to your skin, and to your plaster!

Your next two steps are
1) Order a proper test kit Test Kits Compared
2) Plan to drain the pool and refill it. That's still the most cost-effective way to remove the CYA and copper. You might be able to get a Reverse Osmosis guy in your area. The cost will likely be close to the cost of water, and you'll lose some water in the process to boot.