Switching from SWCG to liquid Chlorine.

[BigDave]

How warm is the water?

[poolaris]

Pool Store did test for copper & iron which were zero. Water temp is between 70-76. I have already turned off SWG and will check CL twice a day and add liquid CL as necessary to maintain 3.0. Yes, PHO was Phosphates, which was high because of high winds with leaf and catkin debry. In spite of keeping pump on all the time during those periods and manually vacuuming, I guess it still crept up. Pool store tried selling "Phosfree". I thought it was a rip, but maybe I was wrong?

[poolaris]

I forgot to add that my pool is concrete. Also Zodiac recommend a salt level of 4200. Last year when I had it tested it was 3800, and as I have not added any salt I think it must be in that ballpark at the moment. Is there any disadvantage in having salt in pool and using liquid chlorine as the sole method of sanitizer?

[kelemvor]

Is there any disadvantage in having salt in pool and using liquid chlorine as the sole method of sanitizer?

Nope. Some people add salt with no swcg because they like the way the water feels with the salt in it.

[chem geek]

With your reported numbers, the saturation index is -0.16 so shouldn't be scaling that much unless your pH is getting higher at times. It's also possible to get calcium phosphate scaling and that might be what is happening in your case. A phosphate remover would help if that were the case, but they are expensive so would not be cheap if it turned out not to be the cause. If you were to lower the TA to 80 ppm and see what happens -- especially since with an SWCG you would normally see the pH rising so it might be higher -- that would be cheaper to try first. If that helped, then you could lower the TA even more to 70 ppm and then add 50 ppm Borates to the pool and that should cut down the amount of pH rise in the SWCG in half.

[poolaris]

As an update to my earlier posts. I have been testing water twice per day, and have found that adding 16oz liquid chlorine at 10% restores my cl level to 3.0 by the following early morning. Evening time it will have dropped to 2.0 and that is when I add the chlorine. Acid use has been reduced although not by huge amounts. I need to add about 1/3rd gall every 3 days to keep it below 8. Now I have a regular pattern going I can probably get away with testing every other day. The whole procedure is vastly quicker than cleaning out that salt cell and bleeding the system every morning and when the cost of replacement cells is taken into consideration the liquid chlorine method is also way cheaper. My phosphate
level is high but there are no signs of algae and the water is still sparkling clear. I do however have really bad scaling on the tile and rubbing with pumice is totally useless, It will need sand blasting next time I drain it. Would there be any point in putting in Phosfree at this stage?

[Spensar]

Phosphates are algae food, but because of the chlorine there is not algae, so the phosphates are not relevant. Phosfree at this point would be moot, unless there is some other reason than algae control.