How do i add phosphates to lower calcium hardness?

[Guest]

i have a 37,000 gallon concrete pool. i am shocking it, but my calcium hardness is 480. everything else is within range. thanks!

[czechmate]

Calcium hardness is essential at certain levels to protect your plaster. Too high CH may result in scaling or deposit of calcium in the pool and plumbing. The only true remedy is a partial drain. But you may consider a temporary remedy that may last well into the season. Since you do not show PH, TA, and other important levels there may be a solutions that will postpone a drain, without raising the calcite saturation index, CSI.
By lowering the TA to 90-100, by lowering the PH to 7.4 - 7.5, and by adding salt to your water. It will lower the CSI and give you piece of mind. I would not go for the "new and improved" expensive gimmick (chemical to lower/suspend calcium), from Leslie's myself. Keep in mind though, that your CSI will be also rising with the rising water temperature. Cloudy water will be the CSI signal prior scaling. Eventually you will drain some water, but this will give you a chance to pick the time and dilute meanwhile.

[czechmate]

Oh yes, I did not even mention, that adding phosphates to a pool is really the last thing you want to do. It is what the algae feeds on. With phosphates at or bellow 100ppm and marginal chlorine level, you have algae free pool. Adding phosphates to your gunite pool is like putting nails in your driveway to keep out door to door salesman.

[polyvue]

Oh yes, I did not even mention, that adding phosphates to a pool is really the last thing you want to do. It is what the algae feeds on. With phosphates at or bellow 100ppm and marginal chlorine level, you have algae free pool. Adding phosphates to your gunite pool is like putting nails in your driveway to keep out door to door salesman.

I love that analogy - can I steal it?

Though you must be right to advise against adding phosphates (no one should maintain an aviary over their pool either) I have to think that phosphates may be overplayed somewhat. I purchased a cheap phosphate kit and was surprised to find only 250 ppm in my pool water -- the same amount as in the city water used to fill it. However, some pool owners seem to get by very nicely with multiples of this and never experience algae outbreaks (I know this from reading and not personal experience.)