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View Full Version : Switching from SWCG to liquid Chlorine.



poolaris
05-09-2013, 04:38 PM
As I currently spend between 15-20 minutes a day in cleaning my salt gen cell I was thinking maybe I could save time and aggro by turning it off and simply adding liquid chlorine instead. My pool is about 14K gall, and cyanuric acid is at 50, I currently keep the CL level at 3.0.

Any idea how much liquid cl I would need to add, preferably every other day, to maintain that level?

Being in AZ the sun shines every day. I was hoping to offset some of the cost by reducing the amount of acid I have to add, which is usually 1 gall a week, and also of course the cost of replacement salt cells every other year. I normally use tablets only when I am away and would do so in the future as that way the pool does not build up high levels of cyanuric acid.

CarlD
05-09-2013, 05:18 PM
You need the SWCG pros to look at. Meanwhile please post ALL your numbers: FC, CC, TC, pH, T/A, CH, CYA, and salt. Something sounds awfully fishy.

JimK
05-09-2013, 07:27 PM
As I currently spend between 15-20 minutes a day in cleaning my salt gen cell I was thinking maybe I could save time and aggro by turning it off and simply adding liquid chlorine instead. My pool is about 14K gall, and cyanuric acid is at 50, I currently keep the CL level at 3.0.

Any idea how much liquid cl I would need to add, preferably every other day, to maintain that level?

Being in AZ the sun shines every day. I was hoping to offset some of the cost by reducing the amount of acid I have to add, which is usually 1 gall a week, and also of course the cost of replacement salt cells every other year. I normally use tablets only when I am away and would do so in the future as that way the pool does not build up high levels of cyanuric acid.

I'm curious why you have to clean the salt cell every day? Mine goes months without the need for cleaning.

kelemvor
05-09-2013, 11:20 PM
I agree, something's not right with that level of scaling. Perhaps really high pH and really high calcium? In any event, to switch to regular chlorination, all you have to do is start dosing chlorine. I don't think you'll know how much to add on a regular basis until you get a feel for it.

Use the traditional method. Identify your target chlorine level based on your CYA reading and the best guess chart (http://www.poolsolutions.com/gd/best-guess-swimming-pool-chlorine-chart.html#a). Then dose chlorine accordingly. Take regular chlorine readings and re dose as needed.

With a 50 cya you want to be between 3-6ppm FC. It takes a little less than a quart of 6% bleach to give you 1% raise in FC in that much water.

You've almost certainly got some other problem leading to the severe scaling though, I'm sure it will manifest its-self in other ways if you don't find and correct that problem.

poolaris
05-10-2013, 03:35 PM
The numbers are as follows: FC=3.0 TAC = 3.0, Salt= 4500, CH = 350, CYA=50, TA= 120,PH = 7.4, PHO =1500. Those numbers were obtained today from a pool store test and were very close to readings I obtained using the Taylor drop test kit excepting those for salt and PHO which I was unable to test myself but the TA reading they had was 20 higher than mine. I assume all that white stuff between the cells is calcium? Anyway, it completely bridges the cell plates - always has. It should be cleaned twice a day and sometimes is. I just thought that was one of the downsides of SWG. 30 years before that I had a pool in which I used tabs but I don't remember spending so much time in maintaining it as this one which I have had for six years. Of course time dims the memory. The other noticeable difference in this one is the amount of scaling on the perimeter tiles as they are virtually light gray and pumice stone rubbing has no effect. The other difference is the constant need to add acid. After this I do not want another SWG even so called self cleaning. I'm not saying my scaling is the result of the SWG as my water has always been crystal clear, I'm just wanting to save some time in the mornings.

CarlD
05-10-2013, 03:55 PM
I am guessing here but I think 1) your salt is too high. 3000ppm is the usual target. 2) If your pool is vinyl there is NO reason your CH is 350...again, too high. If it's concrete or tile, try lowering CH to 200. If vinyl, consider replacing the water with virtually 0 CH. 3) Your CYA should be a minimum of 60 for your SWCG (check your manual) 4) I think your T/A is too high, especially with CH=350. You'll want that down, too. 5) If PHO is phosphates, that's probably irrelevant. 6) You should also have the pool store check for all kinds of metals.

But, as I said, I'm just guessing here.

BigDave
05-10-2013, 04:12 PM
How warm is the water?

poolaris
05-10-2013, 10:30 PM
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
05-10-2013, 10:37 PM
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
05-10-2013, 11:15 PM
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
05-11-2013, 02:31 AM
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
05-28-2013, 01:37 PM
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
05-30-2013, 12:07 AM
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.

chem geek
05-31-2013, 03:24 AM
I'd lower your TA level as that should reduce calcium carbonate scaling on the tile. See the How To Guide to Lowering Swimming Pool Alkalinity (http://www.poolsolutions.com/gd/lowering-swimming-pool-alkalinity-step-by-step.html).