Pool Calcium levels

[PoolDoc]

good deal!

[waterbear]

If you have been relying on pool store testing there is a very good chance that the CH is not that high and it is testing error. Not uncommon at all. Once you do get your kit do the calcium hardness test with a 10 ml water sample, 10 drops of calcium buffer and three drops of indicator (instructions in small print in the lid of the test kt at the bottom of the calcium hardness test section). This way every drop of titrant will equal 25 ppm CH instead of 10 ppm so the test will go much faster for your suspected high calcium levels and you will see the color changes more readily.

[beachfrontpool]

Just got the Taylor kit, and tested all: CH = 800 ppm(!), and the city water input tested at 110 ppm; CYA = 62; Alkalinity = 60. Chlorine and pH were both good, 4.0 and 7.3, I just added sodium hypoclorite and muriatic acid yesterday--it's been quite rainy the last couple days. I can't understand why the calcium is creeping up.

I haven't shocked the pool since we bought the place in May--is this necessary? What does it actually do? The pool doesn't get heavy use--we are only two using this big pool. We just bought new filters--they system takes 2 of the Hayward Star 1200 series. Does filtration affect calcium in concrete pools in any way?

[waterbear]

ust got the Taylor kit, and tested all: CYA = 62

How did you get this reading with the Taylor kit? It is only able to give a CYA reading to 10 ppm and since the measurement scale is not linear, interpolation between the markings is not goin to be any more precison than 5 ppm (and even that is a guess.)

[beachfrontpool]

Yes, the kit is a bit complicated, and I am certainly no chemist. However, the reading levels they advise you to refer to at the back of the comparator tube for the CYA readings range from 30 to 100, where cloudiness obscures the black dot, and 60 was about where it disappeared.

[PoolDoc]

There are two ways you can remove calcium from your pool:

1. Drain 2/3 of the pool, and refill. With pool water CH=800 and fill water CH=110, you should end up with new pool water CH=340, which is acceptable. BUT, be careful to make sure your pool won't float! Dig a 3' deep hole next to the pool, and make SURE it does not fill with water. If it does, don't drain! Empty concrete pool WILL float on a lake OR in ground water!

2. Do lime softening, which involves raising the pH above 10.5 with soda ash, and precipitating the calcium as calcium carbonate, and then vacuuming it out. You'll need to be comfortable using the K2006, and be able to vacuum to waste, before you're ready to tackle this. This will remove more of your calcium, but will be more work. There's a bucket test you MUST do first, to make sure it will work, and that you have the right doses.

Meanwhile, keep your pH between 7.0 and 7.4.