Calcium Hardness

[dax]

I'm a newbie when it comes to spa chemicals.  I've had my tub for two and a half weeks.  When we first filled it, on 06/27, we took a water sample to our dealer.  According to the analysis, our calcium hardness level was 273ppm.  Supposedly it's supposed to be between 200-400ppm.  Took another sample in on 07/06 and the calcium level was 257ppm.  Had it tested again today and it was 187ppm.  Their prinout suggested that I add Calcium Hardness Increaser.  When I got home to do so, I discovered that was not part of our chemical start-up kit so I need to run out tomorrow and buy some.

My question is, what causes the calcium level to drop?  We have an ozonator on the tub along with a complimentarty Nature 2 cartridge.  We shock with MPS after every use and use Dichlor Granular as our sanitizer.  Also, is there any way to test for calcium besides taking a sample to the dealer?  Thanks in advance.

[Vinny]

First thing is unless you are topping off from splashed out water with soft water or the tap water calcium is fluctuating that much, calcium shouldn't decrease - it should be about the same. I don't know how the dealer is testing but if it by computer his calibration may be off.

Second, you can buy test kits to test for calcium, I always recommend the Taylor K-2005 kit - it will test all the water's parameters.

Lastly, depending on who you talk to we all have opinions on everything in spaing and calcium is no exception. Some believe in having calcium and some don't. I personally believe in it as an insurance to keep my water "balanced" and for the soft water not to errode anything. Someone will come along and say that there's nothing to errode so you don't need calcium.

The minimum "recommended" amount is 150 PPM and it's really up to you if you want to persue it. I certainly recommend testing your own water as you have more control over the repeatability of the tests once you get the hang of it.

[tony]

My water out of the tap has a calcium level of 50 ppm.  I generally add enough calcium increaser to bring the level to just over 100 ppm.  At 187, I would just leave it.  I like to keep it on the bare minimum side.  The only reason I add any at all is because I believe calcium helps with clarity but not needed in an acrylic spa or vinyl pool.  The higher recommended levels are definitely needed in a concrete pool/spa.

[dax]

Thanks for the quick replies.  I'll definitely pick up one of those Taylor kits.  I believe I've seen them mentioned in previous subjects on the forum as well.

We have very hard water in my city.  I have a water softener, but the outside faucet bypasses the softener hence the 279 reading when we first filled up the tub.

But stupid me just realized that when we add the MPS and dichlor, we mix it with tap water from our laundry room before dumping it into the tub.  It's easier to do that rather than drag out the hose for the outside faucet.  That's what must be dropping the calciium level.    Guess I'll be dragging out the hose from now on.  Maybe I'll get a quick connect for the outside faucet.

[Vinny]

You don't need to mix Dichlor and MPS with water. Turn on the jets in the tub and throw them in. That's it! Wait 5 or 10 minutes with the jets running, stop jets and close the cover.