Do you trust your SWG?

[Mattikuss]

Hi Friends,

I am a perfectionist with my “chemicals” and am religious about keeping my pH, CYA, FC, and TA in check. I’ve noticed that my SWG, based on the TFP pool math app, is not increasing my FC by the rate that is expected. For example, yesterday, I was at a FC level of 2.0 at the end of a busy, sunny day. According to the pool math app, to get my FC back to a 9.0ppm I needed to run my intellichlor at 100% for 21 hours. It has been 23 hours and my FAS/DPD is reading 7.0ppm. This should have been achieved within 15 hours. A couple
Factors: my pool has been covered for the last 23 hours, my CYA is 70-80, and I have a CC level of 0ppm.

 

[Dirk]

The only thing you should trust are the test results. There are many, many factors that affect FC, pH, TA, CH, etc. And those factors not only can change from season to season, but even daily. Do what you gotta do to get your levels where you need them, and don't sweat the rest.

The exception is if your dosing results are so far off from your predictions that there could be some other problem that needs to be resolved. For example, unexpected FC loss could indicate an algae problem. But that, too, is handled by test results. You'd do an OCLT test to determine if algae is at work. So in this particular instance, you should do an OCLT to rule out (or determine) the presence of algae. Then proceed accordingly. Starting with report your results here for more advice about next steps.

Perform the Overnight FC Loss Test (OCLT)

The Overnight Chlorine Loss Test tells if the SLAM is finished or if you need to start a SLAM. This article says how to do the OCLT.

www.troublefreepool.com

You might also run the "life remaining" test on your SWG, to see how much juice is left in the tank.

 

[Dirk]

IntelliChlor SCG Usage Hours Meter
The IntelliChlor® SCG provides a built-in cell “usage hours” meter that reports how many hours IntelliChlor has been operating. The IntelliChlor SCG is designed to operate for approximately 10,000 hours before replacement is needed or roughly five (5) years of average use.
To access the system status mode:

1. Press and hold the MORE button for three (3) seconds until the lights scroll across the unit.
2. One (1) of the five (5) Sanitizer Output LED indicators (20%, 40%, 60%, 80% and 100%) will be lit,
   indicating the hours of usage. The Output LEDs are as follows:
   • 2000 hours (20% LED on)
   • 4000 hours (40% LED on)
   • 6000 hours (60% LED on)
   • 8000 hours (80% LED on)
   • 10,000 hours (100% LED on)

 

[Bperry]

Hi Friends,

I am a perfectionist with my “chemicals” and am religious about keeping my pH, CYA, FC, and TA in check. I’ve noticed that my SWG, based on the TFP pool math app, is not increasing my FC by the rate that is expected. For example, yesterday, I was at a FC level of 2.0 at the end of a busy, sunny day. According to the pool math app, to get my FC back to a 9.0ppm I needed to run my intellichlor at 100% for 21 hours. It has been 23 hours and my FAS/DPD is reading 7.0ppm. This should have been achieved within 15 hours. A couple
Factors: my pool has been covered for the last 23 hours, my CYA is 70-80, and I have a CC level of 0ppm.

If you let the FC get down to 2ppm, you may have something eating it. Minimum is 4ppm at that CYA level.

 

[TinFoilHat]

Have you tried to bring your FC up to your goal with liquid chlorine? Then do an OCLT and see if you are using chlorine up overnight. The cell can only maintain a level and only if the pool is balanced.

 

[Luric9957]

Since it take 21hrs, did you sub the daily loss of FC (2-3 ppm per day) ?

 

[Newdude]

^^^^^^ this.

Cells are rated for perfect lab like conditions which rarely occur in the real world. Then you lost 4ppm or so as you were producing.

Overnight Chlorine Loss Test to know for sure that the water is healthy.

Then you can run an overnight gain test to remove the sun from the equation. 8 hours of production should get you X FC and it will likely be much closer than what you saw.

 

[Mattikuss]

If you let the FC get down to 2ppm, you may have something eating it. Minimum is 4ppm at that CYA level.

I know, I know. It was a big day, lots of people lots of sun. I’m trying to manage the pool solely with the SWG. I added liquid cl at the start of the year only.

 

[Mattikuss]

^^^^^^ this.

Cells are rated for perfect lab like conditions which rarely occur in the real world. Then you lost 4ppm or so as you were producing.

Overnight Chlorine Loss Test to know for sure that the water is healthy.

Then you can run an overnight gain test to remove the sun from the equation. 8 hours of production should get you X FC and it will likely be much closer than what you saw.

Brilliant. Overnight gain. Never considered.

 

[Mattikuss]

Since it take 21hrs, did you sub the daily loss of FC (2-3 ppm per day) ?

I didn’t. Good thinking. I suppose this math would check out.

 

[Newdude]

Overnight gain. Never considered.

Just to be clear, the gain test means nothing without the loss test first.

 

[TinFoilHat]

I know, I know. It was a big day, lots of people lots of sun. I’m trying to manage the pool solely with the SWG. I added liquid cl at the start of the year only.

You're asking the SWG to do too much. You need to keep liquid chlorine on hand for an emergency at least, then you have it when you need a boost to help the SWG.

 

[jark87]

I know, I know. It was a big day, lots of people lots of sun. I’m trying to manage the pool solely with the SWG. I added liquid cl at the start of the year only.

I don’t add liquid chlorine often - usually only for a SLAM if the situation arises - so I primarily rely on my SWCG. But I keep a couple of gallons of LC on hand just in case.

 

[Dirk]

You're asking the SWG to do too much. You need to keep liquid chlorine on hand for an emergency at least, then you have it when you need a boost to help the SWG.

^^^^ This, 100%. You cannot use an SWG to move FC (I mean you can, a little, but that is not its purpose and so it doesn't function well trying, if at all).

If your FC is low, you have to dose with liquid chlorine back up to your target value, and then use the SWG solely for maintaining that value.

Otherwise, you'll find yourself on an FC rollercoaster (which is where you are now), constantly turning the SWG up or down, chasing the target value.

You also need liquid chlorine on hand to anticipate a big FC drop. Typically that is a big swim party. In advance of the party, you'd goose your FC up a bit in anticipation of a big swimmer load. And even check your FC during the party and "top off" the FC should it fall below the target. You can't do any of that effectively with a SWG.

And then you need some "emergency" liquid chlorine on hand to respond to the odd attack on FC, like a baby pooping in your pool, or "bird strike" or a dead critter in your skimmer.

SWGs replace 90% of the need for liquid chlorine, but not 100%. You need liquid chlorine on hand for that other 10% use.

 

[an1vrsy]

To answer your question, Yes… I trust my SWG! I also trust my test kit. I am a member of #TeamRunHot.

If I am hosting a pool party on a Saturday, on Friday night I crank the IC60 to 100%. For 12 hours with it at 100%, effects of adding shows I could get a 4.6 ppm FC increase. If I started at FC 10 ppm and I test before the party and I am at 14, I accomplished what a gallon of 10% chlorine would have done. That’s why I took the recommendation from TFP to go big with my pool equipment. I am not lugging and storing gallon bottles of chlorine until the water gets below 57* and the IC60 stops generating.

 

[ping]

The best way to solve this issue is to run an OCLT. With SWG pools it is difficult to detect algae at first due to constant chlorine being added that keeps the algae from ever blooming. Usually the first indication of an algae issue is the chlorine is lower than it should be. The pool still looks clear but the SWG seems to not be working as well as it should.

If the OCLT fails, I suggest getting rid of the cover if it is a bubble solar cover. Covers can cause issues with the water and once there is algae in the pool and the cover is on the pool, it is very difficult to remove the algae from the cover. If you go through a SLAM and put the cover back on this issue will repeat itself over and over. Believe me, I've learned the hard way.

 

[Mdragger88]

Hi Friends,

I am a perfectionist with my “chemicals” and am religious about keeping my pH, CYA, FC, and TA in check. I’ve noticed that my SWG, based on the TFP pool math app, is not increasing my FC by the rate that is expected. For example, yesterday, I was at a FC level of 2.0 at the end of a busy, sunny day. According to the pool math app, to get my FC back to a 9.0ppm I needed to run my intellichlor at 100% for 21 hours. It has been 23 hours and my FAS/DPD is reading 7.0ppm. This should have been achieved within 15 hours. A couple
Factors: my pool has been covered for the last 23 hours, my CYA is 70-80, and I have a CC level of 0ppm.

I see you are keeping pool math logs of your additions but not of your test results. I would suggest you start doing so as it makes things easier to understand for us & you to look back on if you have issues.

Along with all the other suggestions- oclt then ocgt etc.
Have you checked your cell for scale build up?

 

[Mattikuss]

You're asking the SWG to do too much. You need to keep liquid chlorine on hand for an emergency at least, then you have it when you need a boost to help the SWG.

Got it. Makes sense.

 

[Mattikuss]

^^^^ This, 100%. You cannot use an SWG to move FC (I mean you can, a little, but that is not its purpose and so it doesn't function well trying, if at all).

If your FC is low, you have to dose with liquid chlorine back up to your target value, and then use the SWG solely for maintaining that value.

Otherwise, you'll find yourself on an FC rollercoaster (which is where you are now), constantly turning the SWG up or down, chasing the target value.

You also need liquid chlorine on hand to anticipate a big FC drop. Typically that is a big swim party. In advance of the party, you'd goose your FC up a bit in anticipation of a big swimmer load. And even check your FC during the party and "top off" the FC should it fall below the target. You can't do any of that effectively with a SWG.

And then you need some "emergency" liquid chlorine on hand to respond to the odd attack on FC, like a baby pooping in your pool, or "bird strike" or a dead critter in your skimmer.

SWGs replace 90% of the need for liquid chlorine, but not 100%. You need liquid chlorine on hand for that other 10% use.

I’ve been doing it all wrong. I’m… shocked… that I haven’t run into a problem yet.

 

[Mattikuss]

I see you are keeping pool math logs of your additions but not of your test results. I would suggest you start doing so as it makes things easier to understand for us & you to look back on if you have issues.

Along with all the other suggestions- oclt then ocgt etc.
Have you checked your cell for scale build up?

Not sure how to log results. I just put in what my Taylor tells me I’m at, and then log the addition.