Stratified rainwater causing SWG shutdown?

Oct 9, 2015
6
Loxley, Alabama
I have a new-to-me 11000 gal pool with an Aqua Rite SWG. Now that the weather is cool and the pool is not used, I only run the pump three times a day for a total of 3 hours, three 1-hour periods.

We have had quite a bit of rain lately along with a couple of leaks which have since been corrected. I've had to add some salt to compensate for dilution and water loss; no surprises there. However, several times I have found the Aqua Rite "Low Salt" and "Check Cell" lights on and noticed that the unit has shut itself down. The salt reading on the panel shows very low, usually below 1000ppm. Yet, a salt test shows the level in the pool to be in the normal range.

I wonder if it is possible that the rainwater is stratified; i.e. floating on top of the heavier salt water. Then, when the pump (and SWG system) comes on, the skimmers suck in the rain water, the SWG detects the very low salt level in the rain water, shuts itself down, and remains that way until I reset it. This makes even more sense to me because if I force the pump to run for a couple of hours and then reset the Aqua Rite SWG, it reads salt in the normal range and functions normally. I am guessing that once the rainwater is mixed in, the Aqua Rite unit is happy. At this point, the salt level indicated on the panel closely matches my salt-test figures. In addition, now that the rain has stopped for a few days, it is working just fine.

When I called the factory, the so-called technician told me that rain dilutes the salt water. Duh...... any 5 year old knows that. Then he said that the SWG does not "kick in" until it runs for an hour and a half and he is never heard of a situation like the one I described to him. That's when I thanked him and hung up. Customer support personnel who do not know the answer to your question is one thing, but making stuff up is worse. I can see that the Aqua Rite does a little "measuring and thinking" when it starts up, but once it detects normal flow and normal salt level, it appears to begin generating within about a minute or so, not an hour and a half. Perhaps the fellow did not understand the difference between seconds and hours.

Anyhow, has anyone noticed a problem with a SWG system shutting down after it rains even though the salt level, once the rain has had a chance to mix in, is still within acceptable levels?
 
Welcome to TFP!

What is the water temperature? If it is too low then you will have issues with cold water.

I would remove the cell and make sure it is clean of any scale. I doubt that the rain water could consistently dilute the water enough to cause the low salt errors, but I wouldn't rule it out either.

From my understanding the AquaRite uses a 100 minute cycle time. If the SWG's output is 10% it will only produce chlorine for 10 minutes of every 100 minutes of pump run time. During the other 90 minutes the SWG will not produce chlorine but it should not give any errors either.
 
I guess I didn't make myself clear. The problem is not that the rain water is sufficient to dilute the pool water to the point that the salt level is too low, although with all the rain we've had plus the significant leak, I did have to add some salt to keep it roughly in the middle of the operating range as measured both by the SWG panel and a chemical test. I am careful to not let the salt level fall too low because I know that will cause the SWG to stop functioning, so I monitor the salt level at least once a day during rainy periods, especially before I had the leaks repaired.

And I know that I'm running the pump long enough to mix the rain water with the existing salty pool water. That is proven by the fact that after running the pump for a while, the Aqua Rite functions normally. I am not worried that the rain water is consistently diluting the pool water enough to cause a low salt warning. That is not my question.

And low water temperature isn't the problem since it measures around 60 degrees, the low temp warning doesn't come on, and when I run the pump for a wile or if it doesn't rain the unit works just fine.

My question has to do with the unit shutting down when it senses extremely low salt levels just after the pump starts following a rain. My guess is that when the pump is off and we have a lot of rain, the fresh water floats on top of the salt water. This is an easily observed phenomenon with fresh river water when it meet the sea and I don't see why it wouldn't apply to a swimming pool. My theory is that when the pump does cycle on, initially it takes in nearly pure rain water (no salt) via the skimmers. The Aqua Rite measures this as an extremely low salt level and produces a low salt warning as it shuts down after a short period of time. This all happens before the pump has a chance to mix in the rain water. Remember, after the pump runs for a while, I can re-set the SWG and it works normally. Or, if it doesn't rain, it functions normally.

By the way, I just recently cleaned and inspected the cell which is less than one year old.

Has anyone noticed this happening to their pool?
 
I have an aqua rite and have not seen this. We get plenty of rain here in FL too. My system is set up so that some water is also drawn from the main drain at all times. Perhaps that is the difference. I've never looked, but I'd be surprised to see the instant salt level to fall to 1000 even after a rain on my unit.
 
50 degrees and less, the unit will shut itself off. 60 degrees to 50 degrees the unit will scale back production to 20 percent. When you refer to the salt reading, are you reading the number displayed on the unit before you push any buttons (average salt reading)? Or do you push the button 5 times (instant salt reading)? Have you cleared or reset the average salt reading?

Clearing the average salt reading:

Slide main switch to auto.
Push diagnostic button until you get the salt display.
Slide main switch to super chlor, then back to auto.
Push diagnostic button to exit.

Weather or not this solves your problem, you may not be able to diagnose your unit properly until your water temp gets above 60 degrees. Since most Chlorine generators shut themselves off during the cold months, you would need to chlorinate by hand through that time anyway.
 
Can you post all of the diagnostics?

Which cell do you have?

How old is the cell (the first part of the serial number contains the year of manufacture. For example, a serial number beginning with 3E09 has a three year warranty and was made in 2009.)

What is the actual salt level?
 
FWIW, this was my recent experience after 7" of rain January 5-7 this year. Our filter pump pulls all it's water from the skimmer and water was around 75d. I got the low salt warning in the morning, which activates at <3000 ppm vs. spec of 4000 ppm. I put my vacuum in the deep end upside down and checked it about 1/2 hour later. The controller fired back up and the "low salt" light was off.

I tested the water from the overflow and the water in the pool. I don't have salt testing yet, and please note that these numbers are from the Aussie 4in1 test kit which is not approved on TFP, but FWIW, here's what I could get. (my K2006 is on the way from America)

18" deep pool water / overflow water
FC 3.0 / 1.0
pH 8.0 / 7.6
TA 70 / 40
 
Mozella,

Do you have a main drain? If so, are you able to switch off your skimmers, and pull only from the main drain? Pull only from the main drain if you can, and see if the problem recurs. If it does not, that would seem to support your stratification theory.

Philip
 

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