New Salt Cell not performing

[Swordfish]

Hey everyone.

I recently replaced my T-15 cell. The other one lasted a really long time and was old and not producing any chlorine.

The new one is working, but not nearly as well as the old one. Right now at 100% for 8 hours and I can barely raise the FC (.5ppm increase). My old cell would have bumped me up by about 4ppm at least. I dont have more than a .5 CC reading, so I dont think anything is in the pool feasting on my chlorine.

The controller is an old aquarite controller with old firmware.

Did Hayward change the product line at all? Or is there an issue maybe with the controller? It reports the salt correctly at 3200, which I confirmed with a liquid salt test kit.

Thanks for any advice!

 

[jblizzle]

Well, something is off in your expectations.

Hayward claims the T-15 will produce 1.4 pounds of chlorine in 24 hours at 100% ... that would be 6ppm of FC in your 28k pool.

So, running for 8 hours should only likely produce 2ppm ... and that does not account for losses that would be occurring to the sun at the same time.

What is your FC and CYA now?

Recommend raising the FC with bleach and performing the Overnight Chlorine Loss Test to confirm there is nothing in the water.

 

[Swordfish]

Jblizzle,

Thank you for that sanity check. I was basing my post on my observations with the new cell. From 2014 through this year, the original salt cell (which I'm not sure how long it was used prior to me taking ownership) would keep my pool at 4ppm with 10 hours of runtime at about 65 - 70%. During that time, I didnt raise the CYA to recommended levels, and the CYA hovered around 40 to 50.

With the new cell, I also decided it was time to raise the CYA, and I have it near 70. I figured the new cell would be "stronger" and have no problem maintaining the FC. So I reduced the runtime to 8 hours, and started at 65%. Now I have it to 100% and my FC is about 2.5.

With the calculations you provided, it sounds like the new cell is performing as it should. But it does make me wonder if the older T-15s may have had a higher output? I'm not sure how else I could explain the apparent change in performance. But it does give me piece of mind. If it is performing as it should, I can easily make the adjustments to runtime, etc to keep the FC where it should be. I just didnt want to make those adjustments if there may have been a different problem.

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One additional question:

I may have to replace my pump soon. IF I go to a variable speed pump, will the lower flow affect the SWG output? Or, does the slower moving water just mean the chlorine will be more concentrated and the SWG output remain the same (provided the flow is high enough to ensure the SWG is operating).

 

[JamesW]

What are the diagnostic readings?

 

[Swordfish]

Cycling through the menu, I see the following values:

3300
83
25.4
6.48
-3200
AL-3
r 1.40

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I skipped 100p, but the SWG is set at 100%.

 

[JamesW]

Those numbers look good. It's working correctly.

With a variable speed pump at low, the efficiency should be close enough not to make a difference as long as the flow switch is closed.

 

[Swordfish]

Thank you for the confirmation! Peace of mind is invaluable.

 

[JamesW]

As long as the salinity reading on the box is accurate, the cell is working correctly.

I recommend the K-1766 to monitor the actual salinity to compare to the box.

 

[Swordfish]

I did use that kit already. Old Salt Cell was reading way below last year, and stopped working this year. 3200 (3300 now due to evaporation) was spot on with the K-1766 kit and new cell.

I always stain my fingers with that kit though... no matter how careful I am. LOL.