Calcium Hardness Levels for Heater

[bottomcat]

I have a Hayward Universal heater and the owner's manual recommends keeping CH between 200 and 400. Mine is at 60. Is it really advised to raise CH that high?

[FormerBromineUser]

Only worry about it if you have a warranty issue. Otherwise, you don't need to raise your CH.

[bottomcat]

My concern was that if I ever need to make a warranty claim, will having low CH be a legitimate reason to deny it? In reading on TFP, it sounds like the "science" behind low calcium being corrosive to metal is rather sketchy. As the theory goes, it is hoped that the calcium forms a protective barrier inside the copper pipes or the calcium decreases the water's affinity for metal. The arguments against this theory are that the calcium carbonate layer doesn't form well inside a heat exchanger (doesn't form well on the cold spots and maybe results in too much scaling on the hot spots) and that taking the calcium out of water (by softening) makes water less conductive and therefore less corrosive (I think).

[FormerBromineUser]

Yup, that's it. How new is the heater? Since we know you don't NEED the CH, if there's ever an issue, raise the CH (and other requirements) before making the warranty call. Not legal advise here, just saying.... What is your handle on that other place?

pH is the most important parameter for heater longevity.

[chem geek]

There are also pools over 10 years old reporting on these forums with copper in their gas heaters and ZERO calcium or in some cases very low calcium in their water and they have no problems whatsoever. My own tap water only has 50 ppm CH, but the municipal water district does add 300-500 ppb phosphates for corrosion control, but that's mostly to prevent lead (and to some degree copper) leaching, not so much for preventing corrosion to the extent that there would be leaks. The pH is also kept higher and that's the most important factor to preventing metal corrosion.

Calcium carbonate saturation is really for protecting surfaces that have calcium carbonate in them including plaster and grout.

[bottomcat]

Thanks chem-geek. I'm learning from your posts. Personally, I changed majors after 3 semesters of Chem-E. ;)

@FBU: I'm just a lurker at TFP. Heater is only one season old.