T-Cell15 / Aqua-Plus Reads Low-Salt Recently After Adding

[randys]

Our newly built pool had no salt all winter. I had been keeping up with liquid chlorine. Finally, our pool vendor brought 15, 40lb bags of salt. I told them to leave it by the garage and not put it in the pool. I tested my water and it read 600ppm. The Pool Math app told me to add 9 bags to get me up to 3000ppm. After 9 bags, and 8hours, Aqua-Plus said the level was still low. The Aqua-Plus documentation says it can take up to 24hrs for the SWG to show the proper reading. So, I tested the water again with the Taylor kit and it read 2800ppm. Pool Math app told me to add another 30lbs, I added 40 (you can see my pool math logs in my profile). 24hrs from the 10th bag, the Aqua-Plus is now reading 2300ppm, claiming it's still too low.

Was the pool builder right to bring me 15 bags? Should I just add everything they gave me, or should I wait a bit longer for the aqua-plus to do its thing? Water is also 59F right now.

 

[YippeeSkippy]

By chance was your SWG still "on" during the time you added the salt?? That can sometimes cause a bit of confusion to the device if it gets a blast of high salt (or any chemical really). You should have the device "off" at those times to avoid potential problems.
Pool Builders are often off the mark in estimating pool volume. I'd go by my own testing and tuck any extra bags away for future use down the road.
Let the water mix for another day or so and re-test. Then check your manual to see about re-calibrating your SWG.

Maddie

 

[ajw22]

SWG salt sensors are not very accurate. They can be off by 500 ppm or more. Just add salt slowly until you make the SWG sensor happy. The discrepancy between the SWG and your testing is not a big problem.

 

[randys]

I had the SWG unplugged while adding salt. The reading on the SWG has slowly been coming up. I think it makes an average based calculation. Last I checked it was up to 2800ppm and the low-level service light finally turned off. Now it's cold again, so I will wait for the water to warm up and try to figure out the rate my Chlorine disappears and what the SWG % needs to be at.

 

[JamesW]

The average salinity takes a while to come up.

Check out the instant salinity for current salinity readings.