Where is all this salt coming from??

[Charlie Bezzina]

Hi, I'm perplexed as to where all the salt in my pool is coming from.

The pool builder put 7 X 20kg bags of salt in my pool in July. In early August I measured the levels using my test kit at 4600. Today I measured the levels using my test kit at 6000!

HCl is really all that's gone into the pool since I got the balance where I want it and were only talking about 7 litres of the stuff over the life of the pool?

Is there any explanation for what is happening, and a long term solution? I'm worried this much salt buildup is going to destroy my SWCG.

 

[Mdragger88]

Have u tested your fill water?

 

[Jimrahbe]

Charles,

Have you been adding any chemicals to your pool? Liquid Chlorine??

Salt will not go up unless you are adding something..

The only other possibility is that you are having a testing error.

How did you test for salt the first time and this time??? What type of test?

Thanks,

Jim R.

 

[Charlie Bezzina]

The pool builder added:
140kg salt
4kg calcium chloride
Unknown quantity cya..

Since the pool builder handed over, I have added in total:

150g unstabilised 70% Calcium hypochlorite
1kg cyanuric acid
1 kg sodium bicarbonate
7kg calcium chloride
7litres hydrochloric acid

 

[Charlie Bezzina]

I have tested both times using the clear choice labs test kit available here in Aus.

The first time I tested I was surprised the number was high, but I trusted it. This time I have no faith in the result and I don't know how to check I'm not overloading the salt chlorinator cell.

 

[Mdragger88]

Is it possible your pool volume is over estimated?

 

[Charlie Bezzina]

No, it's pretty darn close to 38000litres.

In any case, that would not explain the slowly increasing salt levels.

 

[Mdragger88]

Do u have / can u get salt strips, a salinity meter or get it checked somewhere else? Regeants can be bad - I would get another test method to check for that.
Salt Strips can be off a couple hundred ppm but they might help confirm or deny this discrepancy.
Let’s see if we can get someone familiar with your particular kit processes to chime in
@aussieta

 

[aussieta]

i use the taylor k-1766 salt test
i am thinking test error, either your august test or this one
but if builder only added 140 kg your salt should be under 3000ppm
any chance a family member added more salt
pool stores in australia seem close on salt test IMO
so maybe get a pool store water test
need to rinse my mouth out after saying that

 

[Charlie Bezzina]

Ok, I now have one pool store salt test after visiting two pool stores..

One test returned a salt level of 2985.
The other store test returned salt level of 0 because "their salt tester has crashed out" but said the total dissolved solids value of 4040 is indicative of having low salt. Does that sound reasonable?

 

[Charlie Bezzina]

I just redid the salt test twice being super careful and watching every single drop forming on the tip..

First attempt = 4800
Second attempt = 4600

So these numbers match my results from August, but I still think the test from August is way too high. I expect the salt to be 3600 at most.

Where does this leave me... Should I do a partial drain and refill?

 

[ajw22]

The chloride in calcium chloride adds salt.

Will adding Calcium chloride increase the salt level as read by my SWG?

Latest chemistry: FC = 7.5, CC = 0, PH = 7.7, TA = 75, CYA = 40, CH = 225, salt = 3100, temp = 68, CSI = -0.36 (pool math). Based on this I need to raise the CYA and CH. My questions: 1 - Will my salt concentration as measured by my SWG sensor increase when I add 35# CaCl? If yes, is this...

www.troublefreepool.com

Salt for SWG versus Calcium Chloride

Just double checking... I ordered some Snow Joe Calcium Chloride to bring up my CH a little bit (it was at 250). That kind of salt is different than the salt added by my pool equipment guy for SWGs, correct? My salinity won't go up because I added a bit of Calcium Chloride?

www.troublefreepool.com

 

[Charlie Bezzina]

Ok that is helpful.

So by assuming the 11kg cacl2 were just nacl, I can roughly calculate 3963 ppm of salt in total. Still short of the 4600 using the test kit, but closer than 3674.

Is there anything else I have added that might cause a significant increase in salt?

 

[Charlie Bezzina]

Things are getting clearer now. I have tested the calibration solution (4000ppm) being super careful again and it too has returned the result of 4800.

Either my reagents, bottles or technique are not quite right but I think it is safe to assume my tested salt levels are around and perhaps just below 4000 using my test kit.

 

[JamesW]

7litres hydrochloric acid

Is there anything else I have added that might cause a significant increase in salt?

31.45% HCl = 594 grams salt per liter.

7 liters = 4.16 kg of salt = 109 ppm in 38,000 liters of pool water.

 

[Charlie Bezzina]

Thanks. It is interesting that all these products somehow ended up as salt.

I guess a really good pool tech would account for the extra salt when they setup a brand new pool and perhaps add a little less salt initially.