PH going up again!

Hello all. First off I do have and compu pool SWCG on my AG 15x25 52" pool. I had been on here before mentining about my high PH and Alk levels. I used the muratic acid and it came down to the proper level. But it going up again. I have read that some people have this issue with SWCG's! Is it ok to add muratic again to bring it down? It has only been 3 weeks since last edition. My big fear it that my 4 year old daughter has very sensitive skin which was why we choose a SWCG pool to keep levels constant. Will the muratic start to build up and cause skin damage? Does it disipate? Any help would be great.

It is common to have a pH rise when using a SWCG, because of the way it works. If you can drop your TA to around 80 ppm, and drop the pH to 7.6, it will be the most stable, according to the SWCG gurus around this forum ( I don't have a SWCG, but am debating adding one to my pool). It is common to have to add the acid to keep the pH down.You don't have to worry about skin damage due to the acid use, as long as you keep pH above 7.0, and as long as you allow the acid to completely disperse before swimming in it. I have actually accidentally splashed some directly on my hand while adding it to the pool, and just rinsed it off in the pool with no further effects. (Not that we advocate that--you should always take utmost care while handling muriatic acid, because it is nasty stuff--but sometimes accidents happen)

Post a full set of test results and we can better help you. Also, post the make and model of the SWCG and (very important) the test results need to include CYA and TA levels, pump run time, and FC level.

Thanks for your help. I am going to check all the information about my pool and SWCG make and models and put in my signature this weekend. As for the levels I do not have a Taylor yet so I am relying on the pool store. I know this is not good though its the best I can do for now. I know the CYA level is low beacuse I did not realize I still had to use it with a SWCG and my CL levels have been dropping and I am going to burn up my plates. Added some liquid CYA yesterday and have a water sample to take in today. When it is done I will post results.

Ok. Just got back from the pool store and here are the results.
FC 0.2 ppm, TC 0.3 ppm, CC 0.1 ppm, PH 7.9, Hardness 260 ppm, Alk 167 ppm, CA 10 ppm, Phos 100ppm, Salt 3400ppm.
Pump runtime is 12-14 hrs per day in the daytime off at night.
As I had mentioned I just started to the liquid CYA yesterday afternoon and I only used 1/2 a 1 gallon bottle as I did not want to go to high. So I will add the rest later and also somemore Muratic Acid. Pool is totaly clear even with these numbers. Pool is 36000 liters.

Yes, your CYA is low, and does need to be raised, which you are working on.....and I'm willing to bet that Waterbear's going to tell you to drop the alk to around 80 ppm or so and see if that doesn't help slow the pH rise...

Janet

Hello. I have added the Muratic Acid, the last 1/2 of my 1 Gallon liquid CYA and some more salt. Waiting for a few hours of circulation and then I will retest. Also I did this post because I have put all my info about my pool in my signature. Thanks again for everyones help. Carl.

Yes, I absolutely agree that TA needs to be lower. I've found that if your pH trends up, a lower TA is better. If it trends down, a higher TA is better. If it doesn't move, don't mess with it!

Carl

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Originally Posted by aylad

Yes, your CYA is low, and does need to be raised, which you are working on.....and I'm willing to bet that Waterbear's going to tell you to drop the alk to around 80 ppm or so and see if that doesn't help slow the pH rise...

Janet

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I was going to say 70!

More important, with a CompuPool unit you want the CYA at 100 ppm, particularly if you have one of the non reversing ones. This will minimize the cell on time (and the speed at which the cell scales) while maintaining the FC (keep it at 5 ppm or a bit higher with this CYA level). Minimizing the cell on time will mean less generation of hydrogen gas in the cell which means less aeration of the water which means less outgassing of CO2 which means slower pH rise. (Outgassing of CO2 is the main cause of pH rise in salt pools, assuming no new curing plaster.)

Lowering the TA to 70 ppm will also slow pH rise from outgassing.

Thanks Waterbear. My compupool SWCG does switch polarities. Now that I have added the stuff I have I will get the water tested again. A least with waht I have added I am heading in the right direction. I will post the results of my next water test.

Ok. Just back from the pool store with latest results. Since I used the liquid CYA the first time I was able to get a reading today. FC-0.7 ppm, TC- 1.0 ppm, CC-0.3, PH-7.4, Alk-176 ppm, CYA-15ppm, Phos-100ppm, Salt 3800. So looks like I am going in the right direction. I still have 1 gallon of Muratic Acid if I need it and I bought 2lb of powder CYA the liquid cost to much to continue. The store is telling me my CC is above acceptable levels and has a bunch of ways to correct. So what I was hoping someone could tell me where to go from here. All your help is great. The pool is still clear though.

I don't trust the pool store's test results much, but I trust their advice even less. A CC of .5 is not uncommon, especially when you have had a bather load. It just means the chlorine in the water is fighting something. Generally we don't even suggest that you shock the pool unless you have a CC of 1 or more. If your water is clear, there's no sign of algae, and you're not losing any chlorine when testing at night and again in the morning, then your water is fine and you don't need to shock the pool. You do, however, need to get your chlorine up. Even with a SWCG, you should still maintain your chlorine at least 5% of your CYA. I realize with a CYA of 15 that means 0.75, but I don't believe the CYA result either--most testers can't discern a level less than 30 ppm. I would go ahead and add some CYA--with your SWCG you want to target 100 ppm, according to Waterbear. Use the granular, put it in a sock in front of a return, or directly into the skimmer SLOWLY so you don't clog the pipes, and then give it 4-5 days to dissolve before testing for it again.

You're headed in the right direction--you just need to quit listening to the pool store!

Janet

You really, really need to get a good test kit so you can do your own testing. It will make keeping your pool SO much easier, by allowing you to make minor corrections as they are needed, and not waiting until there's a big problem to fix.

Thanks Janet. I am not listening to the pool store just getting my test there. I have only ever added what people here tell me too. I am in Canada and a Taylor kit cost alot here. So as I am new to pools I get the water test done at pool store. What a bout the Muratic should I add? I do loose chlorine during the day that is why I have started to get CYA in there as I was told by my installer the SWCG would look after everything! Which it has I have never had anything but clear water but I have the SWCG running at a hight level to do so and I don"t want to kill it.

Your pH is fine for right now, but you'll need the acid to lower your TA..here's the method that we recommend: http://www.poolforum.com/pf2/showthread.php?t=191

Once you get the TA down, the CYA up, and the pH rise slows down, your pool should be a lot more maintenance free!!

Janet

The thing I find weird is that my PH went down with my addition of Muractic yesterday but my Alk went up by 9ppm. Is this because of not enough airation? I only have one jet to use for this. If I add more acid will my PH not drop even more? Don't want my pool to be a chemical sess pool!!!

I don't think your alk went up with the addition of muriatic acid. Yes, if you add more acid, the pH will go down further. What is your pH and TA now?

On Friday my PH was 7.9 and Alk was 167 ppm then I added 1/2 gallon of Muratic and 1/2 Gallon of liquid CYA got another test Saturday and the PH is 7.4 and Alk was 176.

My guess would be faulty testing....but you could verify that by testing same sample from two different stores.....

Janet

That is likely. I have put in the CYA in a sock so I am waiting for it to dissolve. I think I will add 1/2 gallon of Muratic tommorow and then I wait a few days and get another test. All I am realy trying to acomplish is to lower the runtime and percentage on my SWCG so it will last a few years. Everyones help on this site has been awesome. Thanks to all. After next test I will post results and proceed with the suggestions I receive here.

It is definitely testing error (or more likely, the normal variance from the precision of the test.) You numbers look like their are either from a strip reader or colorimeter. If they are from a strip readier they are just not to be trusted. If they are from a colorimeter such as the LmMotte Waterlink system they are in spec because, if my memory serves me correctly, the LaMotte UDV TA test has a precision of +10 ppm / - 20 ppm for a variance of 30 ppm. (The Taylor titration test, which does not use any fancy meters is actually ore precise with a precision of +/- 10 ppm!)

Thanks Waterbear. Not sure what the test is but no strips are used. My water sample goes into about 6 if not more little clear vials with couloured lids on them. Then they are put 1 at a time into a little red box connected to a computer. After a few minutes they give me printed results. If I can get through this season this way I will purchase a taylor kit throughout the winter. With all the install and setup costs with the pool cash is tight. Thanks everyone for all your help. I will post test results ina few days after CYA have dissolved. Then again I will call on your guideance.

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Originally Posted by Mr.Mooks

Thanks Waterbear. Not sure what the test is but no strips are used. My water sample goes into about 6 if not more little clear vials with couloured lids on them. Then they are put 1 at a time into a little red box connected to a computer. After a few minutes they give me printed results.

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Sounds like a LaMotte Waterlink Express. I know it well and am certified on it by LaMotte. It's good for pool stores since a whole batter of tests is done in 3 minutes BUT it does not have the precision of the Taylor kit and the type of variance you see in test results is common.

Bad new is the CYA and Calcium Hardness tests with this unit are even worse than the TA test with both of these being +10/-25 ppm! (This is a variance of 35 ppm which, for a CYA test is VERY significant!)

Yes Waterbear I clicked on the link you provided and that is exactly the machine they use. Now without having a Taylor what do you suggest? Find a pool store that use a different method? Can I just walk in and ask them? If so what type of test should I be looking for? On the brighter side my CYA power is dissolving very well and with my own OTO kit the Ch seems to be holding better. But I do not have a test for my CYA so I am not sure what it is at currently. I do have strips but they never give me the same result twice.

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Originally Posted by Mr.Mooks

Yes Waterbear I clicked on the link you provided and that is exactly the machine they use. Now without having a Taylor what do you suggest? Find a pool store that use a different method? Can I just walk in and ask them? If so what type of test should I be looking for? On the brighter side my CYA power is dissolving very well and with my own OTO kit the Ch seems to be holding better. But I do not have a test for my CYA so I am not sure what it is at currently. I do have strips but they never give me the same result twice.

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The water link is OK but just realize that the precision of the unit is less than a Taylor testing station (AND if the testing is not properly timed then the results can be off.) It is better than strips. AS to what kind of testing to look for I would say Taylor BUT many pool store employees are not really properly trained in water testing. You really should get your own kit. If you consider how much your pool and SWCG cost then the cost of a good test kit really isn't that much and, with what it will save you in chemicals and maintenance, will quickly pay for itself.