Tonight I add salt to my non SWG above ground pool

[smallpooldad]

The pool is 9000 gal gunite in Hawaii, at an elevation of 1000ft so nowhere near the ocean. The salt measured 400 ppm before putting in additional salt to raise it to it to 1400 ppm using Ben's calculator. Now several weeks later a Taylor Saltwater kit is showing 3000 ppm (15 drops)? But TDS is registering 1800 ppm when it was 560 ppm before. This is weird!

The water feels great, no stinging of eyes, and virtually no salty taste.

But where did this additional salt come from or is the reading or kit bad? Is it bad for the pool to be at 3000ppm?

Use Wal-Mart's liquid bleach, muriatic acid, baking soda, the blue stuff, and Algaecide 60. Have always had an iron problem from flying red-dirt (ferric oxide AKA rust) but this is under control.

Temp 80 F
pH 7.4
Alk 100
Cl 6.0
Hardness 375
CYA 50
Salt 3000?
TDS 1800
Pool Crystal Clear

Help!

[NWMNMom]

Well, I just added 120# of solar salt a few hours ago. The taste is very slightly salty we think, but maybe just our imagination? Anyway, DH came home from a hot, dusty afternoon in the field on a broken down tractor with no a/c - jumped in and immediately said, "What did you do to the pool?" Summary: I big thumbs up! (I opened my eyes underwater with no stinging, my hair is NICE afterwards)

[csevel]

I added 100# of 99.8% pure salt to my 8500 gal. pool yesterday. Don't have a test kit to measure the salinity but I noticed the difference in the water immediately. The pool definitely has a slight salt taste but not at all bothersome. I liked the way my skin and hair felt afterwards and think I'll enjoy opening my eyes underwater without the stinging.

[NWMNMom]

Does anyone know how high the salt content needs to be to keep the water freezing? Are there any real pros or cons on whether or not your pool water freezes during the winter? I am in New England where it gets pretty cold in January...

This is a good question... Does anyone know the answer to this? My mother in law also brougt it up when we told her we put salt in the pool.....

[bryjen]

How long does it take for the salt to disolve. The salt pellets look pretty big.

[The Raddish]

At a guess, I'd say we'd have to increase the salinity much beyond what the 1000 - 2000ppm most of us have been targeting.

I remember from college physics class that the absolute minimum freezing point of salt water is around -20° C. This is only at the point of maximum salinity in which the water can not possibly dissolve any more salt, which is somewhere around 20% salt. These are guesstimate numbers vaguely remembered through the fog of college labs and tests. I don't remember the exact values, but I'm sure I'm close.

Otherwise, any increase in the salinity of water will drop the freezing point by some amount, but I'm not sure if it is on a linear scale or not. Those of us who have added salt to our water will detect that our water will not freeze at 0°C, but maybe at -2°C or maybe a little warmer or colder. In other words, we haven't added enough water to truly make a difference in the freezing point, but we have lowered it somewhat, even if minimally.