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gregk
05-24-2006, 11:11 AM
We have a 12000 gal in ground gunite pool with a SWG. We plan on resurfacing and remodeling the pool later in the year.

My fill water stats are:
pH 8
Alk 110
CH 190 (Southern CA)

My pool water is:
Alk 70
CH 700
CYa 50
I keep the Ph around 7.4, I have to add acid several times a week (SWG)

I am still getting the hang of the CH test in Ben's kit (I get the flakes and purplish color), but the CH is definitely high in the pool.

Do I need to lower it, or can I run it this way through the summer until the remodel? I have a fairly new heater, which I don't want to damage. Is there anything else that should concern me?

Thanks.

GK

mas985
05-24-2006, 12:17 PM
CH at 700 may eventually cause scaling problems. Have you considered a partial refill? Even with the cost of water in CA, it should not be too bad. 1000 gallons costs me about $2. Replacing half your water would only be $12.

If you decide to keep CH at 700, then I would keep your alkalinity low and PH closer to 7.2. This will help prevent scaling or cloudy water but you will have to keep on top of the numbers and don't let the alk and PH drift too far up. Also, with the alkalinity that low, it may be hard to keep the PH in range. You may want to see how it goes for a few weeks before deciding.

gregk
05-24-2006, 02:03 PM
I probably will end up doing the partial drain (I should had been paying attention to this during the rainy season ). There will also be cost for replacing the salt and CYA of course.

We moved to this house 1 year ago, so I don't know the history. What causes CH to end up so high? Does the SWG contribute to this, or did the previous owner's maintenance cause this?

I do have to fight the pH several times a week with Muriatic acid, so I would like to raise the alkalinity if it is safe. It sounds like I have to get CH below 500 before I should raise the alk?

Thanks for the quick reply.

mas985
05-24-2006, 02:34 PM
Your target for CH should be < 400 ppm if possible and even at that, I would not raise the alk much above 80. Based upon your fill water numbers, to get the CH down to 400, you will need to replace 60% of the water. This will also increase your alk to about 95 so you may want to hold off doing anything until your replace the water.