CH

[jwgillis]

The topic is Calcium Hardness. My current CH level in my inground fiberglass pool with a SWG is 180. I raised it to 180 after conflicting recommendations from several sources that resulted in my decision to keep it above 150 by maintaining a 180 level. All other measurements are at TFP's recommended levels as stated in TFP's Water Balance for SWG. I decided to raise my CH level to the recommended 250. When making a final check to ensure I would do it right, I came across TFP's chart titled (just) Recommend Levels where the recommended CH level is 220-320. I checked TFP's ABC's Of Pool Water Chemistry and found the comment regarding CH that stated "fiberglass pools probably need none." On top of all this, I have really ignored my CH level for the last two years (ran between 140-160). I am "pleasently" confused!

Question: What is the proper level for CH in a SWG fiberglass pool?

Explanation: I have followed TFP's advice and I have the near perfect pool. I have dropped from adding 5 supplements to my pool weekly to adding only one (and could do without this one also). My seach for the proper CH level is "to get it ALL right.

Thank you TFP.

 

[Guest]

The idea that fiberglass pools do not need any calcium came from the fact that vinyl does not need calcium and making the (incorrect) assumption that, since both are considered "inert" they will both react the same to pool water in the same way. However, there is evidence that having higher calcium in a fiberglass pool will help prevent cobalt spotting and metal stains.
Also, if there is a warranty on your gelcoat or pool it is imperative to follow manufacturers recommendations during the warranty period or they could very well deny any warranty claim you make.

I checked TFP's ABC's Of Pool Water Chemistry and found the comment regarding CH that stated "fiberglass pools probably need none."
I just read through the section again and could not find what you are referring to.
pool-school/pool_water_chemistry
Question: What is the proper level for CH in a SWG fiberglass pool?
Probably anything above 200 is OK. I run mine as high as 350 ppm and my incidence of staining has all but disappeared. When I let the CH drop (I top off with very soft water) I am the one who wrote the water balance tips for SWGs initially and based my recommendations on observations of my customer's pools and my own. The "recommended levels" was achieved by a consensus of a group of knowledgeable people. Realize that we are talking about a pool and not rocket science so if you test your CH at 230 ppm and I test mine at 250 ppm it is entirely possible that both are pools are actually at 240 ppm because of the limit f the precision of the calcium hardness test.
Explanation: I have followed TFP's advice and I have the near perfect pool. I have dropped from adding 5 supplements to my pool weekly to adding only one (and could do without this one also). My seach for the proper CH level is "to get it ALL right.

Thank you TFP.

.

 

[JasonLion]

The ABC's Of Pool Water Chemistry chapter at Pool School was re-written this spring. The phrase "fiberglass pools probably need none", referring to calcium, did occur in last years version of that chapter. This years version is consistent with the recommended levels and mentions that calcium can help with the metal staining and cobalt spotting issues with fiberglass.

Pool School was written by a number of different people over a couple of years. Several of our recommendations have changed over time. I have slowly been going through and making updated recommendations, like this one, consistent throughout.

 

[jwgillis]

Waterbear ... thanks for the info on CH. Jasonbear ... thanks for clarifying my comment based on the outdated version of ABC's of Pool Water Chemistry ... and for the reminder that current information should be researched before opening one's mouth.

Question: What is the proper method of applying CH hardness (solid) into the pool?

I have read that you dilute it and "pore it into the pool" (which I assume means into skinner basket); and have read to spread it over the water in the deep end.

Thanks.

 

[JasonLion]

If the calcium chloride is ground finely it is alright to spread it across the deep end of the pool. If it is a relatively coarse grind it is better to pre-dissolve it. It can get rather hot when you pre-dissolve it, so take care when doing that.

 

[NYCPOOL]

Does low CH affect the internal parts of a heat pump?