Conflicting Water Requirements Between Heater and Pool??

[Wolfepack88]

My pool (Leisure Fiberglass) recommends calcium hardness between 80-120ppm but Raypak heater recommends between 200-300ppm. I noticed the anode rod for the heater has worn pretty quickly from installation last Sept and this season. I understand low calcium makes the water corrosive and my level is 75ppm so I am about to go get the Clorox hardener and was going to bring up to 120ppm but I don't want to wear out my heater if the mfg recommend minimum 200ppm for fiberglass pools. Which one to follow. My PH is 7.7 and my TA is 70. Which should I follow pool mfg level or heater levels if I follow heater is higher calcium ppm going to damage the fiberglass/gel coat surface??

 

[ajw22]

I understand low calcium makes the water corrosive

That is incorrect. Only low pH into the low 6's and below make water corrosive.

Low calcium makes the CSI overly negative and water aggressive to plaster which can lead to etching in plaster pools. If you don't have plaster or grout then that does not apply to your pool. Don't get confused about water chemistry discussions about plaster pools.

High CSI can cause scaling that can affect fiberglass pools.

Calcium Saturation Index (CSI)

and my level is 75ppm so I am about to go get the Clorox hardener and was going to bring up to 120ppm but I don't want to wear out my heater if the mfg recommend minimum 200ppm for fiberglass pools. Which one to follow. My PH is 7.7 and my TA is 70. Which should I follow pool mfg level or heater levels if I follow heater is higher calcium ppm going to damage the fiberglass/gel coat surface??

Get your CH into the 200-250 ppm range for your heater. Your FG pool will be fine at that level.

Read Calcium Hardness - Further Reading

 

[Wolfepack88]

That is incorrect. Only low pH into the low 6's and below make water corrosive.

Low calcium makes the CSI overly negative and water aggressive to plaster which can lead to etching in plaster pools. If you don't have plaster or grout then that does not apply to your pool. Don't get confused about water chemistry discussions about plaster pools.

High CSI can cause scaling that can affect fiberglass pools.

Calcium Saturation Index (CSI)




Get your CH into the 200=250 ppm range for your heater. Your FG pool will be fine at that level.

Read Calcium Hardness - Further Reading

Ok, I assumed low ph was a bigger issue but the raypak note about low calcium leading to corrosive water through me and my ph has always been good so the anode wearing down led me to think heck they are right no bueno with lower calcium. On my way up to 200pm. Just added 4 bags of clorox calcium increaser by mixing one at a time in my home depot witha paint stirrer in my cordless drill. Mixed up and diluted very quickly