Troubles getting water balanced & salt reading wrong

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me10lee83

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May 18, 2017
26
Orlando, FL
I moved in to my house about 2 months ago, the pool sat being untreated for about a month, then without the pump running for about a week and a half. Since getting everything back up and running in end of April, I've been struggling to get the water balanced properly.

The chlorine had been too high (slowly dropping from about 7 to a little over 5) over the course of a few weeks, despite having to first add water to the pool a few times due to evaporation then lots of rain. Also the pH has been too high. I add the recommended levels of acid, but when I test a couple of days later, it's still too high.
At one point the salt level had been reading low so I added more salt. The salt level was dropping rapidly (several hundred overnight, when there'd been no rain, stabilizer level is within the normal range- don't know the number at the moment) so I was wondering if there might be a problem with the salt cell. I took a sample to the pool store, their salt reading was about 1000 more than the salt cell was reading (2700 vs 3700 I think). It had just been cleaned in acid a couple of weeks before this, and I'd cleaned it out again with water but it made no difference so I took the SWG to the store. They hooked it up to their machine and tested it 2x and it failed both times. Within the next few days, the salt level reading went up (from about 2700 to about 3000 I think). I purchased a new SWG since it had failed and the readings kept changing, hooked the new one up, and the salt level it was reading didn't change.

I replaced the cell about a week ago, I've been out of town for a few days and when I got home, it was reading at 2600. I did a test with salt strips tonight and they read about 3500. This reading of 3500 makes sense with the pool store's reading of 3700 a few weeks ago because it's rained a lot since then. I have checked the instant reading but that too says 2600. I have a AquaLogic and tried looking around (online, checking settings, reading the manual) to see if there's a calibration option but from it doesn't appear there is, just the ability to reset the avg to the instant reading. Since that's wrong too that's not going to help. Still having problems with the pH, the chlorine was low last week so I increased the chlorination % and today the chlorine is too high again. I've lowered that again and hopefully it will even out.

Soo.... all this brings me to my questions
1) why is my brand-new SWG (hayward t-cell 15) reading so far off the actual salt level, and how do I fix it?
2) why can't I get my pH down? Would the salt cell reading wrong affect this?
 
Give us a set of test results and tell us what you are using to test your pool.

The salt tests and the salt reading on the SWG are +/- 300 to 400. They are designed to get you in the ballpark. Accuracy is not important. If your SWG says low salt and the salt test is reasonably close then add another bag.

No, the salt level or SWG readings have no impact on pH.

Depending on what test you are using it is possible that the test is either inaccurate or that pH is higher if it is reading at the top of the range, ie the test says 8.2 but your pH could be much higher. Add muriatic acid to lower pH. It will eventually come in to range.
 
Using taylor k-2006 for testing. The numbers I get were close to the pool store's numbers the one time I've taken water to them since getting my test kit.

Chlorine: 6.4
CC: < .2 (was just a hint of pink after adding the drops)
pH: finally good (~7.5/7.6ish) I did not add any acid yesterday and it was at least 8 then. We got some rain today but not much
Alkalinity: 90
CH: 160
CA: a little over 30

I'll check pH again tomorrow too, see if it's still good. Guess I need to get some calcium chloride to bring up the CH level.

I understand the salt strips are to get you in the range and there's expected to be a difference of a few hundred, but 900 seems too high of a difference. Why such the difference? I don't want to add more salt if it's already actually in the upper range of what it should be.

For the chlorine, any recommendations of what % it should be chlorinating? The pump runs 8 hrs a day. It was at 50 or 55% when we moved in (same run time), After shocking the pool the chlorine level was staying at 8 - 9 so I dropped it down a lot (to like 5 or 10%) for a while and chlorine levels were still too high (though coming down a bit, about 7ish). I replaced the salt cell after it failed the tests and the next time I tested chlorine a few days later it was just a little too low (about 1.5 I think?) so I put the chlorination time back to 55% and now the chlorine level is back up again... guess I shouldn't have made such a jump to the higher chlorination time but figured I'd set it back to what the previous owners used (since presumably they had everything set right, it's a 10 yr old pool). I put it to 35% yesterday. Should I leave it like this a few days to see how the chlorine does, or lower it further, then do small adjustments once the test results are within normal range?
 
It is far better to start with FC higher and slowly work down. Letting FC drop below minimum is a recipe for algae.

The thing that counts about salt is if the SWG is happy and making chlorine.
 
me10lee83 said:
Using taylor k-2006 for testing. The numbers I get were close to the pool store's numbers the one time I've taken water to them since getting my test kit.

Chlorine: 6.4
CC: < .2 (was just a hint of pink after adding the drops)
pH: finally good (~7.5/7.6ish) I did not add any acid yesterday and it was at least 8 then. We got some rain today but not much
Alkalinity: 90
CH: 160
CA: a little over 30
Click to expand...

Your CH is low for plaster. You should be up around 350 to avoid damaging the plaster.

Not sure what you mean by 'CA'. If it is 'CYA' then you are low for SWG. You should target 70-80.

What is your TA? With SWG your pH will tend to rise so most of us try to keep it on the low side.

Based on your .2 precision, I assume you are using the 25 ml sample for the FAS-DPD test. There is really no reason for this level of precision and it uses much more reagent. Feel free to use the 10 ml sample size version of the test (.5 per drop). See Extended Test Kit Directions if you like.
 
svenpup said:
Not sure what you mean by 'CA'. If it is 'CYA' then you are low for SWG. You should target 70-80.

What is your TA? With SWG your pH will tend to rise so most of us try to keep it on the low side.

Based on your .2 precision, I assume you are using the 25 ml sample for the FAS-DPD test. There is really no reason for this level of precision and it uses much more reagent. Feel free to use the 10 ml sample size version of the test (.5 per drop). See Extended Test Kit Directions if you like.
Click to expand...

I usually use 10 ml sample size, but did the 25 b/c the combined chlorine was clearing up after 1 drop so I wanted to get a better reading on that for this post.

As for CA, yes I meant CYA. I'll add more stabilizer. I was going off 30 - 50 being the ideal range based on the book from the test kit.

TA I posted as just "alkalinity", 90. Is that a good level? The book with the test kit lists two ranges, 80 - 100 and 100 - 120, not sure which range I'd fall in.

What about the salt level the SWG is reading? Today it's dropped to 2500 but the test strip is still showing same as yesterday, about 3500. So the salt cell has had a drop in about 500 in a week but the test strip reading has barely changed. I see hayward has a tech support line. Should I call them about this?
 
You'll want to get your cya up to at least 70 and maybe even 80 given your location.

Don't adjust TA unless your PH is swinging. The higher your TA the faster your ph will rise.

The salt level will move around depending on the temperature of the water. Unless your swg says low salt don't stress about it.
 

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I would add another bag to see if that would do the trick. Do the cell wire connections look okay, are they burnt or frayed?

If the bag of salt doesn't do the trick and the wires look okay, you might might have a problem with your mother board or you could have a lemon of a new cell.
 
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