moishe Posted July 12, 2012 Report Share Posted July 12, 2012 I live in an area with fairly hard tap water - 260ppm - and I have neither a decalcifier nor a well with soft water. Therefore I don't have the option of changing part of the water in order to lower the CH. I was targeting 130ppm and the local spa dealer sold me a liquid "hardness stabilizer", consisting of a "mixture of carboxylates". Adding about 25ml to my 1600l spa brought me down to 200ppm. Gradually adding up to 100ml more in steps of 20ml had no effect at all. The CH remains on a plateau of 200ppm. Looking through the old posts I only found one possibly fitting reference to carboxylates: There are other factors as well such as the combination of hard water (CH) with soap. This forms scale (soap scum) with calcium while the TA has very little to do with this. The soap scum is not calcium carbonate, but a precipitate of calcium attached to (usually) two soap molecules (fatty acid salts with a water hating long end and a water loving carboxylic acid group and it is that group that attaches to the calcium forcing the molecule to precipitate out of the water). As you point out, people bring things into the spa and the relatively low water volume per bather means that it doesn't take much to throw things out of whack. Though I agree that the body soaking in a spa can change the pH, I think it is important to quantify that before assuming that a TA of 60 is inadequate, for example. I am going out on a limb in suspecting that part of what is causing the high CH has been felled by the carboxylates and is probably now residing in the filter, but another part is still in solution and is not being touched by them? I guess 200ppm CH is acceptable, but I'd still like to understand what's going on... Quote Link to comment Share on other sites More sharing options...
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