Clear Pool but cannot maintain free chlorine level?

Hello all. I have just had an above ground pool with SWG installed a month ago. It holds 34000L of water.(I'm in Canada). It has a vinyl liner, hayward pump, hayward sand filter and I use a solar blanket at night. The water temp is 86 F. As mentioned in the title the water is crystal clear but I cannot keep any kind of reading of free chlorine. So I did not want to do this but I went to a pool store for a test. These are the results they gave me. My salt level is 2450 and for my gen. it should be 3400(from owners manuel) but the low salt level warning is not going off. Alk is 185, Calcium is 200, Chlorine is 0.2, Stabilzer is 25 and Phosphates are 2500. So this is their suggestion. Clean the deposit off my salt cell(there is a little buildup on the contacts not the plates) to get a better salt reading, use 5 liters of muratic acid to drop Alk level and use a product Phos free to get the phosphate levels down. So with all this being said I don't know what to do? If I start screwing around my water will not be clear anymore? I have done alot of reading on the site and alot say not to trust pool stores, but I am new and did not know where to turn. My 4 year old has very sensitive skin and I want to put the least chemicals in pool as possible to help her that is why we chose to invest in the SWG. Anyone have ideas? I did purchase the products they mentioned but have not started anything yet. Even with my own test I do show a high Alk level. Any help great.

Welcome to the forum!

Add ~ 250 ml 6% bleach to the pool. with the pump running, as soon as possible. Use the acid they sold you to clean the cell (mix it 10 parts water to 1 part acid and let it 'fizz' for about 5 minutes. Then rinse the cell to see if there is still the deposit and repeat , if necessary.

You didn't mention the pH reading, which makes it hard to say if you actually need to lower the alkalinity :o - I'm thiking you don't have to worry too much about it, but might want to eventually bring it down by keeping the pH closer to 7.2 and aerating.

Phosphates are the latest "bogyman" that pool stores are pushing :mad: - unless and until you have a persistent algae problem, don't worry about it:cool:

There used to be a program called 'Bleach-calc 262' (if memory serves) here that would let you plug in your current test results and then tell you how much chemical to add to get you to your 'ideal' set of numbers for your pool. I can't find it now but, if you can post your free chlorine, combined chlorine and pH, we'll be better able to help you address your issue.

Is the SWCG telling you that anything isn't right? (it seems like it's not producing enough chlorine)

Thanks Ted. They did not give me a PH reading on the piece of paper they gave me. But he did say it was high but that is excpected with SWcG's he says! I think he said if memory serves it around 8.0 and that is what is see when I test. All the paper said was my Chlorine is 0.2 not sure if that means free or total?. The SWCG it not telling me anything is wrong it even says my salt levels are good enough. I will clean the cell and let the SWCG test again and go from there. Funny thing is the first person I delt with at the store thought the SWCG was falty and it was purchased there, but the manager said no he thinks it my levels and phosphates are eating the chlorine. I hope it all works out. Looks like I may have spent money for nothing!

Ted probably knows more about SWCGs than me, but a TA of 185 with one is SURE to see you with high pH...too high! But 5 LITERS of Muriatic acid? I wouldn't put 5 liters of ANYTHING in a pool at once other than...water itself.

Here's probably a good set of numbers to aim for, but the SWCG manufacturer's recommended levels should be approached.
CYA: 80
TA: 80
FC: 4 or more
pH: 7.2-7.8

Ted or some of the other pros may give you better guidance but SWCGs DO tend to increase pH. I don't know if it's the nature of the beast or that something's out of adjustment, but with your low CYA, you can use Tri-Chlor tablets in a floater. They are extemely acid and will help control the pH, plus they add stabilizer, which you need as well.

Carl

The poolcalculator.com suggests 1.3 litres of muriatic acid to go from 8.0 to 7.2 with a TA of 185. Perhaps trying half of that and rechecking would be the best approach. Are you in the GTA area?

Thanks Glen. I was going to start with a lower amount. Did not get time last night. I think they were just trying to make a little extra by selling me all the stuff. I am in Barrie.

It is usually best to go with small additions of acid, retest, then redose if needed instead of trying to get to the target with one big dose.

I want to thank everyone who has helped me out on the site with this issue. So glad to have found this site. I am going to start first with cleaning the plates and then add a little acid. I will then recheck my levels after about 2 hours.

You are very welcome!

You're on the right path!:D

It's always a pleasure to help someone who is willing to listen to the advice and do the work involved!

Though there is probably a better place for this; I want to mention the SWCG= rising pH issue. As a result of salt being electrolytically converted to chlorine, a couple of hydrogen atoms are left over. They form a bubble of hydrogen gas which is introduced into the pool via the returns. This causes aeration, which raises pH. The concentration of hydrogen bubbles, per return effects the aeration process (the pools I built in Ct. had ~ 12 returns !?! (7 regular returns, 2 in the steps and 3 low returns)) Because we split the excess hydrogen between 12 returns, I never saw the pH creep often reported- but I certainly did on pools that had 2 - 4 returns. I hypothesize that the hydrogen is more aggressively aerating the water in pools with fewer returns thus causing the constant pH rise:)

Thanks Ted. My pool is an AG so I only have one return which could be even higher PH rise. Once I try the acid a little at a time I will look for a drop. If it does I will just have to keep it in check and if it rises with the SWCG I will bring it down again. My only question is I keep reading when I put in the Muratic Acid I have to aerate but with an AG pool how do I acheive this?

Aerate by pointing the return jet upwards to create as much turbulence at the water surface as you can. A pool full of splashing kids will also aerate.

Hi Mr Mooks,

I'm in Pickering ... looking forward to 38C tomorrow.