With cooler ambient temperatures & less use, the level of FC went from 4.5 ppm to 10 ppm in my saltwater spa. Thus, I decreased the spa runtime from 6 hrs. to 2 hrs. & disabled the SWCG. Much to my surprise the level of FC spiked to 22.5 ppm in one week. With the SWCG disabled, no liquid chlorine added & no use, how could this happen? I am stumped. I would appreciate your input. Thank you.
Spiking FC
- Thread starter Kit
- Start date
- May 3, 2014
- 58,649
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
How are you testing? FC cannot increase if you are not adding chlorine. Are you testing for CC?
Is the spa covered?
Take care.
Is the spa covered?
Take care.
It would take about 1/3 of a gallon (44oz) of bleach to add 12.5ppm to FC in your 2360 gallon spa.
As already mentioned, FC doesn’t rise on its own. Either your SWG is running without your knowledge, or someone is adding chlorine to the spa and you don’t know.
As already mentioned, FC doesn’t rise on its own. Either your SWG is running without your knowledge, or someone is adding chlorine to the spa and you don’t know.
Yes, the spa is covered. I am testing the FC using the TF-100 test kit. Admittedly, I have not checked the CC. But I will do so.
Of course FC won't rise on its own. That's why I'm stumped. No one is adding liquid chlorine. Is it possible that the PentAire SWCG is still generating chlorine in spite of the fact that I disabled that function on the EasyTouch control panel. Seems unlikely.
- May 3, 2014
- 58,649
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
When I do not want my SWCG to operate I create a Feature Circuit to run my pump. I use this in the winter. You can create the Feature Circuit and set it up on a schedule. Then you go to your Pump schedule and turn it off.
I agree disabling the SWCG should shut it down. But I do not rely on that.
Do you remove the cover for a few hours every few days? Are you heating the spa continuously? What is the water temperature of the spa?
Take care.
Take care.
I agree disabling the SWCG should shut it down. But I do not rely on that.
Do you remove the cover for a few hours every few days? Are you heating the spa continuously? What is the water temperature of the spa?
Take care.
Take care.
No, actually the cover stays on all the time when not in use. Maybe I should leave it open for a awhile each day to let the UV rays eat up some of the chlorine. I was also thinking about removing the SWCG during the winter & putting in a "dummy" unit in its place.
The spa temp is set for 65F. Of course, this only applies when the heater kicks on during the 2-hr. daily runtime for the pump.
When the pump is not running, the water temp is about 54 - 57F during this time of year.
- May 3, 2014
- 58,649
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
The SWCG is not likely to be running at all below 60F. The Pentair Intellichlor will shut off (and display a red 'Cold Water' light) when the water gets much below 60F.
At that low of water temperature you are not consuming much FC at all, especially with the cover on. And yes, as you are heating the water, you should remove the cover every few days for a bit to let the water off gas any CC's.
Your SWCG must have been generating chlorine to have the rise you had. Removing it definitely takes care of that. You will need the actual dummy unit as the unions are proprietary to Pentair.
Take care.
At that low of water temperature you are not consuming much FC at all, especially with the cover on. And yes, as you are heating the water, you should remove the cover every few days for a bit to let the water off gas any CC's.
Your SWCG must have been generating chlorine to have the rise you had. Removing it definitely takes care of that. You will need the actual dummy unit as the unions are proprietary to Pentair.
Take care.
Thank you, Marty. Would it be preferable to have the cover open while the heater is running?
- May 3, 2014
- 58,649
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I do not think that matters. Why do you run the heater if you are not using the spa? Medford is not that cold. I would think the spa being covered and having freeze protection set on your pump would suffice.
Take care.
Take care.
Thanks, Marty. I run the heater during the 2-hr. pump runtime in the early evening so that if we decide to use the spa, the set temperature of 98F will be reached more quickly. Also, during the winter months, the ambient temperature can drop into the teens or even to single digits.
cfherrman
TFP Guide
Use the oto tc tester and the extended test directions to confirm high clorine and eliminate testing error.
Typically holding temp for several days is cheaper than letting it cool down and reheat several days later, so depending on your use cycle one or the other will be cheaper.
Typically holding temp for several days is cheaper than letting it cool down and reheat several days later, so depending on your use cycle one or the other will be cheaper.
I rely on the FAS-DPD test (in the TF-100 test kit)for checking FC weekly. Every 2-3 days I use the OTO test.
Everything being said, I am still stumped on the FC level spiking. If I cannot determine what is the cause, I will assume that the SWCG is somehow producing chlorine even though it is disabled. The fix seems to be replacing the SWCG with the PentAir dummy unit during the winter months.
- May 3, 2014
- 58,649
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Up to you but you can be sure the SWCG will not come on by using a Feature Circuit instead of your pool circuit. You can still set a schedule and have your heater run.
I think the dummy cells can be had for $30 or so.
Take care.
I think the dummy cells can be had for $30 or so.
Take care.
Earlier in this thread, Marty asked me what my CC level was. I checked it today & it's 2.0. This is obviously high. But is this related in any way to the current high FC level of 18?
Thank you.
Thank you.
- May 3, 2014
- 58,649
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Hmmm. Probably not related to the FC but the high CC shows the pool needs to be uncovered for sometime on a regular basis.
I would still think that the SWCG was not completely off during the time your FC spiked.
Take care.
I would still think that the SWCG was not completely off during the time your FC spiked.
Take care.
My thinking regarding the SWCG is the same. SO, I picked up a dummy cell & will replace the SWCG today. That should address any possibility that the SWCG wasn't completely shutting off.
To reduce the high FC level, I added a small amount of granular chlorine neutralizer. I will check the FC level today, as well as recheck the rest of the chemistry since the high FC level might have made the other chemistry results less than reliable.
To reduce the high FC level, I added a small amount of granular chlorine neutralizer. I will check the FC level today, as well as recheck the rest of the chemistry since the high FC level might have made the other chemistry results less than reliable.
- May 3, 2014
- 58,649
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
What was the active ingredient of the chlorine neutralizer? Hydrogen peroxide is the cheapest method for the future.
pH is only test effected by FC above 10ppm.
pH is only test effected by FC above 10ppm.
I used a product called Thio-Trine which is apparently sodium thiosulfate. I did not know that hydrogen peroxide was an alternative. Thank you for the tip!!
Looks like I have all of the chemistry back within range, except TA = 50ppm. Aiming for a target of 100, I was surprised that 94 oz. of baking soda is needed (according to Pool Math) for my 2,500-gallon spa.
Looks like I have all of the chemistry back within range, except TA = 50ppm. Aiming for a target of 100, I was surprised that 94 oz. of baking soda is needed (according to Pool Math) for my 2,500-gallon spa.