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SWIMMING POOLS
CALCIUM
Measuring For Hardness In Pools (2/5/99)
White Deposits On Pool Tiles (7/9/98)
Increasing The Hardness Level In Pool (5/7/98)
Calcium Scale On Pool (5/1/98)
Measuring For Hardness In Pools (2/5/99)
Q:
I am confused about the measurement of hardness in pools. Some informations states that I should be concerned with total hardness while other sources state that only the calcium hardness matters. Some of the test kits that I have tried that are supposedly measuring calcium hardness are in fact giving me a total reading when compared to more accurate test methods such as AA for calcium. What is the truth in this matter. Should I be measuring total hardness or just calcium hardness.
D.K. - Loveland, CO
A:
Hardness is of concern in a swimming pool as a means of controlling the corrosive or scaling properties of water. Calcium chloride is used as a means of increasing the calcium hardness level in pools. The testing is probably just like you describe. I don't believe that it matters to any great extent, whether you test for calcium or total hardness -- either way you are controlling corrosive or scaling tendencies.
In nature calcium predominates and in pools the walls of masonry pools contain calcium. Maintaining calcium levels in a pool is not a precision thing. Close should be good enough. The magnesium contribution in a typical pool is not of critical importance.
Simplicity is of great importance, especially when you are dealing with lay people trying to act like analytical chemists. The tester manufacturers probably have chosen the particular methodology based on convenience and have equated both terms in a practical sense.
I hope that I have been helpful.
Sincerely,
Alan
White Deposits On Pool Tiles (7/9/98)
Q:
My pool-concrete is two years old. The water in our area is very hard, and the tiles have some whitish deposits on them, and some also have some black area, which I'm not sure is a deposit or algae. It doesn't rub off. Is there a cleaner that I can use without harming the water? We are in a drought, and I really don't want to drain and refill. Or should I just try scraping it with "Scotchbrite" or a brush without cleaner?
D.F. - Spicewood, TX
A:
You need to use a strongly acidic cleaner. This will help dissolve the calcium deposits.
To prevent a recurrence, add SUN Super-Quest.
Avoid using any products containing calcium to avoid increasing the hardness level.
Good luck.
Sincerely,
Alan
Increasing The Hardness Level In Pool (5/7/98)
Q:
I was told I needed to increase the hardness level in my vinyl lined, inground pool. It is currently at 50. One person said I should use Calcium Chloride the other said use Calcium Carbonate. Which should I use, or are they the same ?
K.K. - Marshall, TX
A:
Calcium Chloride is the chemical that should be used to raise the calcium hardness level of the water.
The test results for total or calcium hardness are expressed in PPM of Calcium Carbonate. Calcium Carbonate is considered insoluble in water.
I hope that I have cleared up the matter.
Sincerely,
Alan
Calcium Scale On Pool (5/1/98)
Q:
Is there a way of reducing the calcium concentration of a pool without draining the water? Our water and pool are 7 years old. The tiles are badly stained despite many attempts to clean them.
R.K. - Ceres, CA
A:
Sounds as if your pool has started to form scale. In your situation, I would recommend exchanging some water with fresh water. Test the water and the fresh water for calcium. Try and figure out how much water needs to be exchanged to lower the calcium level to 200-400 PPM. At this level, scaling should not be a problem, so long as the pH and total alkalinity are maintained within the appropriate limits.
Cleaning the tile with an acidic cleaner, should help clean them up.
Avoid products containing calcium and acidic pool water conditions, in order to minimize future calcium build-ups.
I hope that I have been of assistance.
Sincerely,
Alan |
