Not generating Chlorine due to high phosphates

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JoeGolan

JoeGolan

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Bronze Supporter
Nov 2, 2016
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Palm Coast, FL
I have 750 Gal spa with a T-cell-3 for SWG. The T-cell-3 is about 5-1/2 years in use

The SPA is in use all year so there is no closing for the winter (We are in FL)

Normally during the winter I keep the setting to 3% and during summer months I raise it to 6-7%. These settings have maintained my chlorine levels well.

I noticed that my chlorine levels had been dropping so I tried upping the percentages without any change so I suspected the cell was at the end of life. I pulled the cell and had it tested and it came back good so we started to search for another issue. My local Pinch-a-penny came back with a Phosphate reading of 2500 and it may may be higher as 2500 was the max of the scale on the test they ran. I also noticed on the diagnostic screens that the voltage and amperage readings were "normal" but the cell shut down after a few minutes of operation and the diagnostics then said "Percentage met"

They gave me a phosphate remover to use running the filter 24 hours, clean the cartridge and run for another 24 hrs before retesting.

Now here is the kicker, my wife all of a sudden (before adding the phosphate remover) broke out in a rash all over her body and went to see a dermatologist who asked her if she was involved in any gardening lately. I believe the Dr thinks she had a reaction to strong chemicals, maybe phosphates. She was in the spa 2 days before we discovered the high phosphate reading so I am putting 2+2 together.

I called Hayward about the cell still not generating chlorine today and they immediately asked me if I knew the phosphate levels. I told them it was measured 2 days ago at 2500 They told me to keep reapplying the phosphate remover and it may take 10-12 days before the levels come down.

We do not have a clue what drove the phosphates up so high. The spa is in a mesh cage (lanai) and according to my landscaper they have not applied anything lately to the shrubbery around the lanai but did fertilize the lawns and also applied a fungicide.

Does this make sense????
 
They "gave" you phosphate remover? I bet they sold it to you ;)

Around here we generally feel there is no point in worrying about phosphates. The phosphates will not prevent the SWG from working. The problem is that your FC got too low for your CYA level, then something started growing in the water and now that is consuming the FC faster than the SWG can make it.
 
Phosphates are not likely relevant to the problem.

I don't think that they can cause rashes (check with doctor to be sure).

Check the cell for scaling. Clean only if there is visible scale.

What are all of the diagnostic readings?

What is the actual salinity?

If the rash happened quickly after using the tub, chemical sensitivity is likely.

If the rash took time to develop, it's likely bacterial from low sanitizer.

Have you used bromine in the tub?

Have you used a ph lock product?

Note: I am not giving medical advice and am not qualified to do so. Any medical issue should be treated by a qualified doctor.
 
Are you just not seeing any FC, or is there a warning light on the SWG?

If you run the thing and collect a sample right at the return, it should read much higher than the pool FC level. If it is, it's working and something is eating the chlorine as fast as it can be made.
 
jblizzle said:
They "gave" you phosphate remover? I bet they sold it to you ;)

Around here we generally feel there is no point in worrying about phosphates. The phosphates will not prevent the SWG from working. The problem is that your FC got too low for your CYA level, then something started growing in the water and now that is consuming the FC faster than the SWG can make it.
Click to expand...

CYA was just slightly low, added stabilizer (1 ounce) and that solved that issue.

Oh and yes I had to pay for the phosphate remover :cool:
 
JamesW said:
Phosphates are not likely relevant to the problem.

I don't think that they can cause rashes (check with doctor to be sure).

Check the cell for scaling. Clean only if there is visible scale.

What are all of the diagnostic readings?

What is the actual salinity?

If the rash happened quickly after using the tub, chemical sensitivity is likely.

If the rash took time to develop, it's likely bacterial from low sanitizer.

Have you used bromine in the tub?

Have you used a ph lock product?

Note: I am not giving medical advice and am not qualified to do so. Any medical issue should be treated by a qualified doctor.
Click to expand...


Yes, phosphates can cause skin irritations but I could not find any definitive guideline on how the concentration is affects the condition or severity

Cell was clean when I removed it for testing at the pool store, no evidence of any scaling

TC =0
FC=0
CC=0
pH=8.0... a little high
TA=120... a little high
CH= 400
CYA=55... a little low
Salt=3300

Cell diagnostics = 28.16V, 2.87A, 71*F, salt 3000, flow switch indicates "Flow", Cell Temp 71*F, Water sensor 76*F, Air sensor 61*F

The rash started started to appear the next morning after being in the spa

I do not use Bromine

I do not use a ph lock product
 
Richard320 said:
Are you just not seeing any FC, or is there a warning light on the SWG?

If you run the thing and collect a sample right at the return, it should read much higher than the pool FC level. If it is, it's working and something is eating the chlorine as fast as it can be made.
Click to expand...

Not measuring any free choline, only warning light on Aqua Plus panel is when salt gets too low, it does not monitor chlorine.
When I first start up the pump, I see the cell go active after the built in delay, after a few minutes the amp reading will go to "0" and and say "percentage met".

Chlorine measured at return jets has a slight reading but since the cell is shutting down it does not really produce that much.
 
JoeGolan said:
Not measuring any free choline, only warning light on Aqua Plus panel is when salt gets too low, it does not monitor chlorine.
When I first start up the pump, I see the cell go active after the built in delay, after a few minutes the amp reading will go to "0" and and say "percentage met".

Chlorine measured at return jets has a slight reading but since the cell is shutting down it does not really produce that much.
Click to expand...
"Percentage met" means it has run for the programmed amount of time. If you set it for 10%, it will run 10% of the time, not all the time at 10% capacity, nor until FC concentration is 10%. It's like a microwave oven. It's either on or off, and it cycles when set less than full power. Isn't there a boost setting on that to get it cranked up to 100%?

I really suspect that you have something growing in the water, which is consuming the chlorine the SWG is producing and also causing your wife's hot tub rash. Yes, it's common enough to get a nickname. https://www.cdc.gov/healthywater/swimming/swimmers/rwi/rashes.html
 

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Richard320 said:
"Percentage met" means it has run for the programmed amount of time. If you set it for 10%, it will run 10% of the time, not all the time at 10% capacity, nor until FC concentration is 10%. It's like a microwave oven. It's either on or off, and it cycles when set less than full power. Isn't there a boost setting on that to get it cranked up to 100%?

I really suspect that you have something growing in the water, which is consuming the chlorine the SWG is producing and also causing your wife's hot tub rash. Yes, it's common enough to get a nickname. https://www.cdc.gov/healthywater/swimming/swimmers/rwi/rashes.html
Click to expand...

Yes I can boost it up and did bring it to 100%.....same result after a few minutes the cell shut down saying the percentage was met. I also have a "Super Chlorinate" option that is timed (I think 10-12 hours and then it would return to the normal setting (%)

That all being said the water is crystal clear, no growth on the walls/floor/steps.

Is it possible that the high phosphate reading is causing the swg to not properly respond?
 
JoeGolan said:
Yes I can boost it up and did bring it to 100%.....same result after a few minutes the cell shut down saying the percentage was met. I also have a "Super Chlorinate" option that is timed (I think 10-12 hours and then it would return to the normal setting (%)

That all being said the water is crystal clear, no growth on the walls/floor/steps.

Is it possible that the high phosphate reading is causing the swg to not properly respond?
Click to expand...
Someone else will have to answer that. I'm one of those Luddite jug-dumpers.
 
Phosphates at 2500 is my concern and confirmed by Hayward as to why the SWG shuts down prematurely
Click to expand...
Let me get this straight. Are you saying that Hayward has actually said/confirmed that the high level of phosphates has caused the SWG to shut down or malfunction?
 
At 3% your cell will only run for 5 minutes per 180 minute period. You just need to increase run time.

The rash is probably bacterial from low sanitizer.

Phosphates are not relevant in my opinion.

Your cycle time is 180 minutes. It should run the percentage of 180 minutes per cycle. If you set it to 50% and it only runs a few minutes and shuts down saying percentage met, it's a bad board.
 
My phosphates were way over 2500 when I opened my pool 2 years ago - had it tested at a Leslie's. I have never added a phosphate remover and my T-15 works fine.

They did try to sell my a phosphate remover specifically for salt water pools, but the kid had already given me the bottle to use for pool water samples, so I passed on it.

Sent from my iPhone using Tapatalk
 
The pool companies always try to blame it on phosphates and it's just not true. The entire problem is the fact that your sanitizer level got too low. The phosphates will not stop the swg from generating chlorine. Phosphates are effectively food for algae, well if you keep your chlorine level high enough the algae can't live so it doesn't matter how much food there is.
 
Remember that phosphates are measured in parts-per-billion...so 2500ppb = 2.5ppm. Phosphates at that low a concentration will hardly cause chemical rashes the doctor is talking about. IF phosphate rashes were common, then many municipal water suppliers would have some very unhappy customers as they often use phosphate and phosphonate based metal sequestrants in their water supplies.

James is right, hot tubs can actively grow psuedomonas bacteria (aka, "hot tub rash") when the FC gets too low and those bacteria can produce and colonize bacterial biofilms. So, not only do you need to get your FC back in line but I would say your spa needs to be purged with a biofilm remover like Ahh-Some.

Is this spa part of a pool or separate?
 
woodyp said:
Let me get this straight. Are you saying that Hayward has actually said/confirmed that the high level of phosphates has caused the SWG to shut down or malfunction?
Click to expand...

BASICALLY Yes, I told my story to Hayward tech support and his first question to me was "Did I test for phosphates and what was the number? I told him the test results listed it as 2500 but it might even have been higher as that was the max reading the test could perform to. He said get the number down and the swg will start functioning.

I just got back from the pool store after doing another phosphate test (they had said to retest after 48 hours following the first dosage) and low and behold we are now seeing some chlorine readings (generated by SWG, no liquid chlorine added), phosphates are still high, now at 2000 but they are moving down. They recommended for me to re-run the phosphate removal process and even double the dosage of the remover. Retest again in another 48 hours.

So if both test readings were right and the first dose did remove 2500, that would mean that the phosphate starting number was more like 4500.... does that make a difference?

- - - Updated - - -

JoyfulNoise said:
Remember that phosphates are measured in parts-per-billion...so 2500ppb = 2.5ppm. Phosphates at that low a concentration will hardly cause chemical rashes the doctor is talking about. IF phosphate rashes were common, then many municipal water suppliers would have some very unhappy customers as they often use phosphate and phosphonate based metal sequestrants in their water supplies.

James is right, hot tubs can actively grow psuedomonas bacteria (aka, "hot tub rash") when the FC gets too low and those bacteria can produce and colonize bacterial biofilms. So, not only do you need to get your FC back in line but I would say your spa needs to be purged with a biofilm remover like Ahh-Some.

Is this spa part of a pool or separate?
Click to expand...

This is a built in spa.... no pool involved
 
JoeGolan said:
This is a built in spa.... no pool involved
Click to expand...

Don't bother with phosphates right now, they are not going to shut down an SWG. I would make this point - a nascent algae bloom and/or tub with lots of biofilms can easily start consuming chlorine. In fact, that's what SWG pool owners will report - "my cell isn't generating chlorine even though it is on..." and then they start to manually chlorinate, SLAM and then everything starts working again. My guess is you might have a dirty tub that needs to be purged. Ahh-some is a great product for cleaning out spas and hot tubs. I would suggest you purge the tub, dump the water, start over with a fresh fill and go from there. I don't imagine 750gal of water in FL costs all that much...
 

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