Curious?

May 19, 2011
66
Corpus Christi, TX
Pool Size
13500
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
Ok, So I haven’t been as vigilant as I usually am on checking my readings because of the colder than usual winter or weather we have had here in South Texas. But all has been good... I still have a sparkling clean pool and all my readings have been good for the most part... I haven’t checked my CYA or Salt in a while somewhere like 4+ months I always had my CYA at 80 and like 3 to 4 months ago give or take, I checked it and I was at 70 well the day before yesterday I checked it and I was at 40 according to my readings...Now grant it we have had some big down pours and I have vacuumed the pool and even backwashed a few times plus had to top off the pool quite a few times... Yes We have had wierd weather down here. It can go from overcast muggy and drizzly 30’s to sun shining bright and hot such a beautiful day 80’s over night and so on and so fourth... So anyways my CYA jumping down to 40 raised a RED FLAG!!! So I was figuring maybe my reagents were going bad so I decided to do something that I NEVER EVER DO... I took a sample of my water to the pool store to get a 2nd opinion (Leslie’s Pool Supplies) Well after having my numbers and them testing and comparing to their numbers to mine I was surprised to see that we weren’t that far off... all of our numbers matched except CYA and Salt... (I’ll post pictures of our readings if y’all want) But on my CYA Test I read 40ppm and Leslie’s Read 50ppm not to far off... That should be an easy fix being that I could add a little at a time and test to see where it goes... On my salt Test I read 3400ppm and Leslie’s read 3000ppm and I’m not sure what the device they used to check that is called... But I used the Taylor Sodium Chloride K-1766 kit so I am curious as to if I should add salt? My SWG is showing 2800ppm but I’m guessing it could be due to the age of the cell or the temp of the water so I have 3 different readings and don’t know which to believe... Also if my CYA dropped so much my salt should have also right? [emoji848] Anyways if anyone has any input I’d love to hear it... Thanks All...
 
b,

I am not sure there is any direct correlation between CYA and salt levels dropping...

As far as the salt readings, I would go with your K-1766.. but I think it has an accuracy of +/- of 200 or so. Not sure about your specific SWCG salt readings, but I would not trust any of them to be accurate when the water temp is below 65 degrees... Even when working, my Pentair cell is rated as only +/- 400...

Thanks for posting,

Jim R.
 
For your CYA test, perhaps your water temperature (if still cold like here around S.A.), could also be influencing that CYA test a bit? You last checked your CYA back in Nov or so (70), so consider a generous CYA reduction of 5ppm per month (that's 20 ppm), plus a few backwashes and water replacement (maybe 5-10 ppm), then the +/- 10 ppm variance in that test anyways, it's conceivable that your CYA is actually about 40-50 now.
 
Generally speaking the readout on the chlorinator is reading conductivity rather than actually measuring salt. The conductivity reading is converted to a TDS or salinity reading using a conversion factor based on the mix of different ions typically found in the water. Depending on where you are and whether you have significant levels of other ions present it may vary from the actual salt content. The wet chemistry kit is measuring chloride content and expressing that as sodium chloride. It should be closer to the real value as long as care is taken with the sample volume and good technique with the drops. The approximate difference between your results and the pool shops could be as little as one of you was half a mL over volume and one was half a mL under volume on a 10 mL sample add in a single drop difference in titration and you're there. That's not too bad for this type of test.
 
Thanks for the feed back everyone... So at what water temp do you think I would get a more accurate reading? Should I hold off on adding anything to the pool as of now and let the water temp rise some to get a more accurate reading? My levels as of yesterday are...

FC - 6
CC - 0
pH - 7.6
TA - 110
CH - 210
CYA - 40
Salt - 3400

Not sure on the precise Water Temp as of right now cause I need to get a new thermometer the one I had broke But it didn't feel too cold... Anyone have a suggestion or good brand to look for?
 
B,

I see no rush... As long as the water is warm enough to allow your salt cell to work, then having a CYA of 40 this time a year is not much of an issue... You will want to get it up to 70 or 80 before the summer gets here..

Everything else looks pretty good to me.

Thanks for posting,

Jim R.
 
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