My CH level has gone from 300 ppm to 500 ppm in a year, with only temporary and insignificant reductions as a result of rainwater additions. I attribute the rise of the CH to fill water concentrated by evaporation. Realizing that it won’t be long before the escalating CH will reach a tipping point and manifest itself with the appearance of other problems, I’ve been seeking a method to lower the CH without a partial drain and refill – a Magic Bullet, if you will. I don’t want to drain and refill because its expensive, inconvenient, and disruptive of the other components of pool water balance.
The pool is a 20,000 in-ground plaster pool. The current water test results are:
FC = 2.8
CC = 0.0
pH = 7.5
Alk = 70
CH = 500
CYA = 80
NaCl = 3,200
Borate = 50
Temp = 86.4°F
The (municipal) fill water test results are:
FC = 0.4
CC =0.0
pH = 7.8
Alk = 150
CH = 170
Here’s a potential method I found, and I’m soliciting the analysis and comments of folks more knowledgeable in the chemistry department than I am. (Are you reading, Chemgeek?) As you can see, this involves the use of trisodium phosphate, and I’m kinda sorta reluctant to add a phosphate to the pool water.
http://www.deh.enr.state.nc.us/ehs/chem.htm
“To lower calcium hardness anhydrous trisodium phosphate may be used. One pound trisodium phosphate per 10,000 gallons will lower calcium hardness 11 ppm. Use in small increments or clouding may occur. Another method of lowering calcium hardness is to simply drain off part of the pool water and dilute the remaining water with fresh make up water.â€
http://www.watermaid.com/help/alltopics ... .htm#Scale
“Another method is to precipitate the calcium as Tricalcium phosphate by the addition of trisodium phosphate. 1 lb. of anhydrous trisodium phosphate will precipitate 1 lb. of calcium carbonate. This is readily removed from the bottom of the pool by vacuuming.â€
The pool is a 20,000 in-ground plaster pool. The current water test results are:
FC = 2.8
CC = 0.0
pH = 7.5
Alk = 70
CH = 500
CYA = 80
NaCl = 3,200
Borate = 50
Temp = 86.4°F
The (municipal) fill water test results are:
FC = 0.4
CC =0.0
pH = 7.8
Alk = 150
CH = 170
Here’s a potential method I found, and I’m soliciting the analysis and comments of folks more knowledgeable in the chemistry department than I am. (Are you reading, Chemgeek?) As you can see, this involves the use of trisodium phosphate, and I’m kinda sorta reluctant to add a phosphate to the pool water.
http://www.deh.enr.state.nc.us/ehs/chem.htm
“To lower calcium hardness anhydrous trisodium phosphate may be used. One pound trisodium phosphate per 10,000 gallons will lower calcium hardness 11 ppm. Use in small increments or clouding may occur. Another method of lowering calcium hardness is to simply drain off part of the pool water and dilute the remaining water with fresh make up water.â€
http://www.watermaid.com/help/alltopics ... .htm#Scale
“Another method is to precipitate the calcium as Tricalcium phosphate by the addition of trisodium phosphate. 1 lb. of anhydrous trisodium phosphate will precipitate 1 lb. of calcium carbonate. This is readily removed from the bottom of the pool by vacuuming.â€