Disappearing Calcium Hardness

[Tomcat]

This question is about my spa.

I've taken care of my pool for three years now without any problems. In dealing with my pool, the only way to lower calcium hardness was a partial drain and refill.

Now to my spa. I started it up about a month ago and got everything in balance. Initial calcium hardness was set to 250. Just did another calcium hardness test and the result was zero! Same test set, same test chemicals, taken one month apart. Where'd my calcium go??? The only thing I can think of is it all calcified in my heater, but is that possible in just one month? Ph and TA all pretty much held in check (although constant adjustments are required - much harder than taking care of a pool).

Thanks

[sammyk]

Did you test for calcium before or after adding other chemicals? I think it should be checked before adding anything to the tub.

[Tomcat]

The test sample was taken before the addition of any chemicals.

I tested the water right after taking the sample as well as after letting it sit for an hour to cool off, both times same result; spa - zero calcium hardness.

Test kit and chemicals same as previous testing.

I tested my pool water with satisfactory results, CH right where it was before for at 275.

Therefore two possibilities 1) CH consummed by something, or 2) something else in my spa water messing with the test.

[Jim_The_Jim]

The test sample was taken before the addition of any chemicals.

I tested the water right after taking the sample as well as after letting it sit for an hour to cool off, both times same result; spa - zero calcium hardness.

Test kit and chemicals same as previous testing.

I tested my pool water with satisfactory results, CH right where it was before for at 275.

Therefore two possibilities 1) CH consummed by something, or 2) something else in my spa water messing with the test.

If you use any of the liquid pH balancers, they can precipitate out the calcium and dump it on the filters, jets, and ruin the heater.

[Tomcat]

I've used muriatic acid (like a teaspoon full at a time) to bring down the ph, but I've never heard of a reaction of it with calcium harness. I do the same with my pool and haven't had any problems.

[Jim_The_Jim]

I've used muriatic acid (like a teaspoon full at a time) to bring down the ph, but I've never heard of a reaction of it with calcium harness. I do the same with my pool and haven't had any problems.

That will not reduce Calcium.

Having an extreme high pH can reduce Calcium.

Having a chemical added that causes the precipitation of calcium is another.

The third is a bad test on the CA.

If you have copper in the water, the copper will ruin the Taylor test for Calcium.