Salt cell reading high on the panel but water doesn't feel salty at all

Started by tampapoolguy · · 3 replies
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#1
My own pool, not a customer's for once. Panel's showing salt level reading fine, right in range, but the water chemistry's acting like there's barely any salt in it at all, cell's barely kicking on and FC drops overnight. Pulled the cell and it looks clean, no scale buildup, plates look fine to my eye. Checked it with test strips just to cross reference and got a number way lower than what the panel claims. Had a customer a few years back with a similar mismatch and it turned out to be a bad flow sensor, but this is a different brand cell than that job. Anybody dealt with a panel just lying to you about salt level before trusting the readout over an actual test. Not ready to drop money on a new cell if it's something dumber than that.

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#2
Tampa, before anything else, what did you actually test the salt with besides the strips, a proper drop-based titration kit or just the strips themselves? I ask because strips are notoriously bad at salt specifically, worse than they are at FC and pH even, and I've seen people chase a phantom problem for weeks because the strip undersold the actual salt level. My TF-100 has a salt titration in it and I trust that number a lot more than any panel or any strip. If all you've got to cross check is the strip reading, I'd get a real titration or send a sample off before you start pulling the cell apart or second guessing the board, because right now you've got two readings that could both be wrong in different directions and no way to know which one's lying.
#3
Alan's right that strips are weak on salt but I wouldnt call it a wash between two unreliable readings, in my experience the panel is usually the one lying before the strip is. My AquaRite read fine on the display for like two weeks while my actual salt was drifting low from splashout and topping off with plain water, panel just doesnt recalculate in real time the way you'd think, it only updates the number when you tell it to recheck or sometimes not even then. So if youve got a titration kit or even just took a sample to the pool store for their drop test, id weight that over the panel every time.

Only other thing, you said the cell looks clean with no scale, but did you actually check the amp draw or just eyeball the plates? Mine looked totally fine visually for months before I found out the readings were off, looks can be deceiving on these things. Anyway if your real salt comes back low thats probably your overnight FC drop right there, cell just cant produce enough at low salt even if it looks fine and panel says its in range.
#4
Not my department on the chemistry side but Dana's onto something with that flow sensor comment from your own post, I'd pull the union right before the cell and check for a cracked o-ring or slight air gap feeding it before you trust either number, a lying flow reading will make the whole panel's math garbage regardless of actual salt content.