Aquarite Salt Cell - Not Generating Enough

[Elvon]

OK, Pool Noob here.

Just moved in home with pool and had brand new T940 Salt Cell installed. We cannot seem to get any chlorine into the pool. Continually get zero free chlorine readings with 10 hrs+/day running the filter pump Had the water tested at Leslie's several times and they are stumped too. Pool is 25k gallons

Most recent water test reflected 3100 PPM Salt. They recommended adding another bag of salt to raise the salt level. We already added 2 bags to come up from 2900 however the salt reading on the Aquarite already says 3400. I've tried to manually re-calibrate using instruction found various places on the web but the salt reading really will not settle below 3400.

The salt cell size is set correctly.

Is 3100 and 3400 within normal measurement error?
If we add another bag of salt is there a chance the cell will shut down?

Other ideas?

Thx!

 

[mknauss]

Welcome to the forum!
What does the pool water look like? The likely scenario is you have algae in your pool that is consuming the chlorine the SWCG is generating. Can you post a full set of test results from your own test kit?
I suggest you read ABC's of Pool Water Chemistry.

 

[Elvon]

Thanks for quick reply. The pool is crystal clear The water looks beautiful.

Here's the most recent test from Leslie's

Chlorine: 0.04
Free Chlorine: 0.04
pH: 7.4
Total Alkalinity: 77 (Added 2.5 lbs alkalinity up)
Calcium Hardness: 275
Cyanuric Acid: 35 (have CYA to add)
Iron: 0
Copper: 0
Phosphates: 0
Salt: 3100

 

[mknauss]

You need a proper test kit. I suggest the TF-100 A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols. Add the Taylor K1766 salinity test kit.

If you are running the SWCG at a 100% generation for 10 hours per day, you are adding 2.9 ppm FC per day to your pool. That is probably close to what you will lose each day to UV and swimmers.

Add 10 ppm FC worth of liquid chlorine. The run a Overnight Chlorine Loss Test. You will need the test kit above to complete the tests.

 

[Dtkokay]

To recap, get a good test kit. A salt cell is good for maintaining your chlorine level but not always good at increasing it. I recommend adding 10 ppm of liquid chlorine (as suggested above) to raise your floor FC level. In other words, instead of staying around almost zero FC, increase FC to 10 ppm and let your salt cell hold that level.