SWCG Percentage With "Cold" Water

revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
I seem to be easily able to maintain 6.5-7.5 PPM chlorine with the SWCG set at 4%. This is with water temp in the mid 50s (pool is 'closed', heater off, solar cover on). My understanding was that my SWCG is limited to 20% output between 50 & 60 degrees F. To me this means that it is running at 4% since that is below the 60 degree/20% threshold. Am I correct or does that mean it is actually running at 20% of the 4% setting, or .8%?
 
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JamesW

TFP Expert
Mar 2, 2011
17,358
Note: Output is scaled back to 20% of desired output setting at 60°F and output stops at 50°F.

So, whatever percentage is shown on the digital display gets multiplied by 0.2 to give the actual percentage.

A setting of 4% would be 0.8%.

The cycle time is 180 minutes. 0.8% of 180 is 1.44 minutes.

You can verify the actual run time by checking the amps to see if it's producing or resting.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
12,432
Evans, Georgia
In these cold months I find it much easier to just turn the SWG off and use liquid chlorine PRN. The chlorine lasts so much longer in cold weather and it avoids me wondering "Is the water warm enough today to make the SWG work??". Testing is more infrequent in cold weather.
Come spring I'll turn it back on again.
 

revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
In these cold months I find it much easier to just turn the SWG off and use liquid chlorine PRN. The chlorine lasts so much longer in cold weather and it avoids me wondering "Is the water warm enough today to make the SWG work??". Testing is more infrequent in cold weather.
Come spring I'll turn it back on again.
I thought like you at first then I decided it was much easier to let the SWCG do its job. I have to pull back a leaf net and a solar cover to add chems, a clumsy procedure, the less I have to do that, the better. I'm thinking I paid all this money for an automated system, why am I out here pouring gallons of bleach in my pool?
I don't have to wonder if the water is too cool, I glance at the wireless thermometer readout occasionally as I walk by it. We're lucky, haven't seen the pool water drop below 53 here all winter.
My only reason for shutting down the salt cell wouId be to extend it's life but with it working for so short a time per day to hold the desired chlorine level, doesn't seem like cell life is significantly impacted.
 
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revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
The cycle time is 180 minutes. 0.8% of 180 is 1.44 minutes.
Can you please explain that a little more? My filter runs for a four hour period each day. Does that mean it produces chlorine for 1.44 minutes of the first 180 minutes and then another 1.44 minutes of the final 60 minutes of run time?
 

JamesW

TFP Expert
Mar 2, 2011
17,358
Can you please explain that a little more? My filter runs for a four hour period each day. Does that mean it produces chlorine for 1.44 minutes of the first 180 minutes and then another 1.44 minutes of the final 60 minutes of run time?
Yes, that should be correct. To verify, move the switch to off and then back on and check the amps.

The amps should show some value for about 2 minutes and then be zero for the remaining 178 minutes.

 

revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
Please bear with me, check my math:
My T15 cell raises my chlorine level 1.47 PPM in 24 hours running 100% (from Pool Math 'Effects of Adding')
1.47 / 1440 minutes (24 hours) = .001 PPM/minute
My cell is generating chlorine 2.88 minutes per day (1.44 x 2)
2.88 x .001 = .003 PPM/day
I'm maintaining my target chlorine level adding .003 PPM chlorine per day? Seems unbelievable. Where am I going wrong?
 

JamesW

TFP Expert
Mar 2, 2011
17,358
With a solar cover and cold water, your loss rate can be very close to zero.

You can verify the actual production of chlorine by checking the amps to see if it's producing or not.
 

revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
You can verify the actual production of chlorine by checking the amps to see if it's producing or not.
I'd have to catch it producing in those 2.88 minutes out of the four hours right? Does it start running right at the beginning of the cycle time, for instance right as the pump kicks on at the beginning of the four hour run time, and at the beginning of the second cycle at three hours?
 

JamesW

TFP Expert
Mar 2, 2011
17,358
Move the switch to off and then back on. Check the amps. wait 2 minutes and then check the amps again.
 

revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
I performed the suggested off/on test to see how long the salt cell would run given the 4% setting at 53F. After a delay countdown the volts/amps reading appeared. Reading was approx 7.0V, 4.3A. It remained so for approx 7min/40 sec and then the readout indicated 'chlorinator off, percentage met'. Tried the test twice with the same result.
If my calculation is correct, 7min/40sec is approx 4% of the 180min cycle time. I suspect that the 20% max cell run level spec between 50-60F water temp means that the cell will run at whatever it is set at, up to 20%. I doesn't seem that the intended interpretation of that spec is that it runs at 20% of the actual setting.
 

JamesW

TFP Expert
Mar 2, 2011
17,358
Interesting. Thanks for the information.

Maybe Aquarite is different from Prologic?

Maybe you're correct that the output only scales from 0 to 20%.

Your volts and amps don't look correct.

Are you sure about the readings?

What is the instant salinity?
 

revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
Your volts and amps don't look correct.

Are you sure about the readings?

What is the instant salinity?
Just checked the readings again. 27.2/5.8 so they're moving around a little. Instant salt reading is 3600 and that's exactly what it tested at this morning.
The unit is actually a Hayward Aqua Plus, not an Aquarite.
 

JamesW

TFP Expert
Mar 2, 2011
17,358
Go to diagnostics and press the + button to start a new cycle and see what the numbers are.

Once they stabilize, press the + button again and see what the new numbers are.

Pressing the + button reverses the polarity and begins a new cycle.

If the amps and instant salinity are significantly different in different polarities, then the cell is probably scaled or failing.
 

revitup

Well-known member
Nov 30, 2019
70
Pawleys Island, SC
Go to diagnostics and press the + button to start a new cycle and see what the numbers are.

Once they stabilize, press the + button again and see what the new numbers are.

Pressing the + button reverses the polarity and begins a new cycle.

If the amps and instant salinity are significantly different in different polarities, then the cell is probably scaled or faili
The cell's only about 4 months old.
+26.90/+5.49 3600
-26.89/-5.54 3600
 

JamesW

TFP Expert
Mar 2, 2011
17,358
Ok, looks good.

To monitor the performance of the cell, divide the instant salinity by the actual salinity.

This number should stay relatively consistent over time.

When the cell begins to fail, you will see the ratio begin to fall.

If the ratio drops below 75%, it's time for a new cell.