Chlorine rising even with chlorinator off?

[smithj51]

Hi all, I have an in-line chlorinator (no salt) (CMP power clean ultra). I added more tabs than usual to the chlorinator without reducing the flow rate which made the free chlorine rise too high (rookie mistake!). I turned off the chlorinator by rotating the flow rate dial counter-clockwise as indicated in the product instructions, and the chlorine continued to rise. It is only falling now because the tablets have almost completely dissolved. I know the chlorinator was fully off because it was not filling with water when the pump was on.

Can anyone tell me why this happened? Why are the chlorine tablets continuing to dissolve and enter the pool when the chlorinator is off?

Thanks!

 

[Texas Splash]

Why are the chlorine tablets continuing to dissolve and enter the pool when the chlorinator is off?

Welcome to TFP! It's been a long time since I used a tab tower. Mine was a different make/model, but even if I had it on it's lowest setting it always had "some" water traveling into the tower where the tabs were stacked. I wonder if that was happening to you as well? Maybe another CMP owner will confirm.

On a side question, as a frequent tab user, are you monitoring the CYA level as well? Just to avoid a large FC-to-CYA ratio disparity down the road? Have you seen our FC/CYA Levels?

Also visit the TFP ----> Pool Care Basics

 

[nuttyp]

Yes indeed welcome to TFP! I'm with @Texas Splash on tab chlorinators... In my experience there are far too many downsides to using them. I owned at least 4 different models (not yours but others) across a few different homes and pools, as well I've helped friends who insist on using them. Simply stated, they don't work - or at least they don't work for more than about a year and you wind up constantly fussing with them. My theory is they just cannot hold up to the dissolving cyanuric acid and chlorine levels they dispense. And it gets worse for any upstream or downstream equipment in the path. For example if you have a heater most of them require a check valve to keep the chlorinator from back feeding into the heater when the pump is off. That's fine, then you learn that the toxicity also reduces the life of check valve, maybe it rots out a flow meter, maybe it back feeds the expensive heater without your knowledge, and perhaps it similarly reduces the life of valves downstream too. And the chlorinators fail in every way imaginable - they either do what you're seeing or they stop dispensing entirely, the control valves are fussy as all get out, so you replace parts and then they crack or leak and you change out feed tubes. All the while you're paying todays inflated prices for the tablets and your CYA levels might be climbing anyway - to the point where you have to stop using tablets for some months - or else drain part of the pool. Based on TFP / pool school I stopped using tablets in favor of liquid chlorine, then got still smarter and went with an SWG (Salt Water chlorine Generator). Now I swim far more and fuss with chemicals far less! Granted the initial SWG cost is tough to swallow, but you're no longer regularly buying, hauling, storing and handling nearly as much chlorine (save on bleached out shirts and shorts and automobile carpet!) - just some liquid to have for a shock/SLAM process if needed or for general cleaning. And no more expensive tablets to buy and store. Granted you still have to test the water, eventually you have to add CYA (aka stabilizer) but it's far easier and cheaper than tablets. And with a SWG you have to add an occasional 40Lb bag of salt - that being cheap and much easier to haul than chlorine. About 3 or 4 bags per year where I am, due to splash out and especially summer rains overflow. But if you're as stubborn as I was, and my friends are, you'll ignore this and wrestle with the tablets etc for a year or two before relenting. In any case, very best wishes! - Joe