Liquid chlorine & unwanted salt

[timjwilson]

I've been doing the BBB method using liquid chlorine only since March 2016. I live in Arizona, water is precious, so my hope was to not have to change the pool water for several years at least. When I first started this method, I realized the limiting factor was going to be salt - according to PoolMath, 1ppm of FC adds 1.6ppm of salt, so the salt level will eventually reach a point where it must be dealt with. But I calculated: assuming 2ppm FC/day, that's +3.2ppm salt/day; if I allow 4000ppm max salt then I can go 1250 days or 3.5 years before it gets too high.

However, after 15 months, I'm measuring 2500ppm TDS (using a TDS meter I bought on Amazon - not sure if I can trust it, but it is brand new for what that's worth). My CH is 350 so I'm assuming the that the remaining 2100ppm is salt.

Under my original assumptions, after 15 months=450 days, I should only have about 1400ppm of salt. So it seems that the salt level is increasing about 1.5x faster than I originally calculated. Not good news!

The liquid chlorine I'm using is HASA Sani-chlor 12.5%.

Regarding my original assumption of 2ppm FC/day -- this is a typical number I see mentioned on the forum. It's hard to say if this is what my pool is actually using since it varies so much through the year...in June, it uses (considerably) more than this, but during winter, much less.

Advice, anyone? What could account for the higher-than-expected salt level? What am I missing?

 

[domct203]

You should check your salt level with the Taylor K-1766.

When I was getting ready to switch to a SWG I found my actual salt level to be about 15% less than my calculated level based on past chlorine usage. This would make sense as you would lose salt from splash out, top offs, overflow from rain etc.

BTW- all forms of chlorine add salt. If you want to stop the accumulation of salt you could switch to a SWG.