FC zero in SWG pool

John,

**** EDIT my cut and pasting errors made it to where this didn't make sense. Now fixed****
Now we're starting to get more information the picture is becoming clearer. TFP methods are pretty simple and very effective. They rely on simple tests so we start with accurate information then we use simple tools to figure out what to do that results in a perfect pool at the cheapest cost. Here's what we know:
  • Pool size
  • swg brand, model - this tells us you are supposed to make 5.3 ppm in 24 hrs at max conditions
  • Your logs indicate you've had way over 5 ppm but you don't have logs frequently enough to really diagnose. The FC levels indicate you must be doing something in addition to run your swg that raises the FC.
Here's what we don't know:
  • What are your settings
  • Daily test results for a few days
  • What else are you adding?
  • How old is your swg?
  • How are you testing salt?
If it were my pool here's what I'd do:
  • Raise FC to 9 ppm with LC (see chart clip below)
  • Turn swg on at max and run 24 hr
  • Check FC, CC, pH
  • Report the numbers here
  • Fill out signature so we don't have to read through all the posts to find out basic information about your pool. Our volunteer experts only have so much time available. This gets you answers your questions quicker and helps them be productive with their volunteer time. It's simple, here's how.
  • You'll get advice on the next step quickly right here.
Your cell is too small for your pool but may work for a year or so, especially at your location up north with relatively short season as @Jimrahbe mentioned. Cells degrade over time so if your cell barely keeps up to start with it will degrade to the point you need to add LC which sort of negates the benefit of swg. So we recommend 2x size. I only know of two that make the enough. Circupool and Pentair as @PoolStored mentioned above. Eventually, when yours doesn't produce enough I would switch to one of them. Automation systems figure in to this decision a little but in my opinion it's not very leveraging. If you buy the same brand swg as your automation you can control % power and run time. In your case there's not an swg available that will make enough FC so it doesn't really matter. Yes, you can run two but that's unnecessarily complicated and expensive. You don't need to change % power that often. You should be able to get by with max power and adjust run time only unless You and you can do this until you start needing more FC than your unit makes. Then buy one of the 60 size units and set it up with run time control only. You can use your existing system to do this if you have a spare relay and most installations do. You'll have to set % power manually but that isn't usually required more than every year or so. I'm in a similar situation where I need the largest size. I bought a Circupool RS 60 because it was the best price/# chlorine at the time. I'm ambivalent on brand since my automation doesn't control % power on either and both of these have good warranty, reputation here.

I hope this is helpful.

Chris

View attachment 598362
Chris, thank you for a thoughtful response. I wish I knew some of this information when we built the pool last year. This is our official first season. My current settings are as follows: Run pump 9-3 daily with SWG @50 % with spillover. I test my pool weekly and as needed. I do not do daily tests regularly - so as I am slowly figuring out, may not be the best idea. I make adjustments to my chemicals based on my test results. Mostly adding Murartic acid weekly. I never had to do anything with the chlorine because it started so high. I have added calcium, CYA when needed. All my equipment is brand new and less than 1 year old. I am testing my salt levels with my TF-Pro test kit.

My new values from today are:
FC - 5.5
CC - 0.5
pH - 7.8

(I finally filled out the signature page - thank you for the helpful link).

John
 
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Chris, thank you for a thoughtful response. I wish I knew some of this information when we built the pool last year. This is our official first season. My current settings are as follows: Run pump 9-3 daily with SWG @50 % with spillover. I test my pool weekly and as needed. I do not do daily tests regularly - so as I am slowly figuring out, may not be the best idea. I make adjustments to my chemicals based on my test results. Mostly adding Murartic acid weekly. I never had to do anything with the chlorine because it started so high. I have added calcium, CYA when needed. All my equipment is brand new and less than 1 year old. I am testing my salt levels with my TF-Pro test kit.

My new values from today are:
FC - 5.5
CC - 0.5
pH - 7.8

(I finally filled out the signature page - thank you for the helpful link).

John
John,

Great response and thank you. As you can see from the screen clip you need to have 4-9 ppm at your CYA level and good that you're maintaining CYA level. This makes it easier to maintain FC using your swg. I would target the top of your range or even a ppm or two above. Expect it will cycle in a range based on many things that change all day long like sun, bather load, other weather. You want to have the bottom of your range at 9 ppm to start. Eventually you can drop it a little but not to where you are now. You are too close to min and that invites algae issues. Since you already dropped to 0, I would run an OCLT test tonight. If algae is present (you usually can't see it initially) it should be at a low level and you can perform a quick SLAM to get rid of it. You should also maintain FC with LC until we make sure you don't have any issues with that. Once you're out of the woods on algae you can transition to swg. To do this start at 100% with for 18 hrs. Pump speed can be as low as you can go and still have enough velocity to keep the swg in line switch open. Usually this is around 1700 rpm. You won't be using much power at this speed but your swg will make as much as it makes at full speed. If your FC level is 9 ppm when you start the swg it should maintain this. Check FC, CC, pH daily 'till you get the pool stable. Eventually you'll be able to back way off. But every pool is different and you need to get to know your pool before you try to go to every other day then 2 times per week and maybe get to weekly. I'm not sure how much Pool School you've done so I've added OCLT instructions below.

I hope this helps. And be sure to ask any questions you have any time. There are always plenty of people to help.

Chris

Overnight Chlorine Loss Test
 
John,

I forgot two other items. What does your pool look like? Clear, cloudy, green or black algae anywhere? Also, the settings I gave you should produce 4.1 ppm FC which should handle normal loads. If after you confirm SLAM isn't needed with your OCLT test tonight you will need to watch the FC trend. If it goes up slightly you can drop run time a little. If it goes down you do the opposite. It is very important to confirm you don't have any algae. If you do your swg won't keep up. Also very important to remember your FC will trend up and down. One of my favorite expert quotes is from @Jimrahbe "if you try to run it at a constant point it will drive you nuts". So check it daily as you learn your pool and when running at these higher levels you can wait a couple days to change the swg setting. This process usually locks in settings within a week. And when it does you're on the way to TFP easy street!

Chris
 
John,

I forgot two other items. What does your pool look like? Clear, cloudy, green or black algae anywhere? Also, the settings I gave you should produce 4.1 ppm FC which should handle normal loads. If after you confirm SLAM isn't needed with your OCLT test tonight you will need to watch the FC trend. If it goes up slightly you can drop run time a little. If it goes down you do the opposite. It is very important to confirm you don't have any algae. If you do your swg won't keep up. Also very important to remember your FC will trend up and down. One of my favorite expert quotes is from @Jimrahbe "if you try to run it at a constant point it will drive you nuts". So check it daily as you learn your pool and when running at these higher levels you can wait a couple days to change the swg setting. This process usually locks in settings within a week. And when it does you're on the way to TFP easy street!

Chris
I will try the test tonight. Keep you posted!

Thank you again!
 
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John,

I forgot two other items. What does your pool look like? Clear, cloudy, green or black algae anywhere? Also, the settings I gave you should produce 4.1 ppm FC which should handle normal loads. If after you confirm SLAM isn't needed with your OCLT test tonight you will need to watch the FC trend. If it goes up slightly you can drop run time a little. If it goes down you do the opposite. It is very important to confirm you don't have any algae. If you do your swg won't keep up. Also very important to remember your FC will trend up and down. One of my favorite expert quotes is from @Jimrahbe "if you try to run it at a constant point it will drive you nuts". So check it daily as you learn your pool and when running at these higher levels you can wait a couple days to change the swg setting. This process usually locks in settings within a week. And when it does you're on the way to TFP easy street!

Chris
Chris
So my pool has been clear this entire time. I completed the OCLT test. Here are my results:
10:21 PM - FC 7.5, CC 0.5
5:55 AM - FC 6.0, CC 0.5
Do I SLAM?

Thank you,

John
 
Yes. Follow the process. Link-->SLAM Process
Thank you.

What’s the maximum amount of chlorine I could add at a time to reach SLAM level? I read through the instructions and says I have to add/test 3-4 times a day so trying to understand how to practically do that without ruining anything.

Thanks again!

John
 
Download pool math. Configure your pool. Enter current FC and SLAM target FC. Choose Liquid Chlorine and enter the % concentration. It will tell you how much to add.

LINK-->PoolMath

3-4x per day is MINIMUM. In the heat of summer, test and replace FC every 2 hours if you can.
 
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Download pool math. Configure your pool. Enter current FC and SLAM target FC. Choose Liquid Chlorine and enter the % concentration. It will tell you how much to add.

LINK-->PoolMath

3-4x per day is MINIMUM. In the heat of summer, test and replace FC every 2 hours if you can.
I understand that, sorry I wasn’t clear but I’m asking what is the maximum amount I can put at a time? I.e. the Pool Math says I need 5.7 jugs so do I put all that in at one time or X amount at a time?

Thank you.
 
Yes add it all, there's no need to space chlorine out. If anything, the bleach lost some strength and you're a little under your target in the end.

PH is best adjusting 0.4 at a time.

Calcium is best dosing in thirds for large batches.
 
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John,

SLAM in your case should be very quick. One of the main reasons owners get into extended SLAM's is because they are afraid to add that much FC. So long as you do not exceed SLAM level for your CYA level you will not harm anything. We also suggest you check frequently and bring it back to SLAM as often as every 3-4 hrs. Doing more than that has diminishing returns but won't hurt. Notice we don't say go way higher than SLAM either. This prevents going to levels that could cause damage. Make sure you check pH first since the drop test is not accurate above 10 ppm FC. Properly calibrated hand-held pH probes do work but it's not necessary.

Here's wishing you a fast, successful SLAM on your way to pool care the easy TFP way!

Chris
 
Hi,
I am currently in the process of my SLAM. Will my readings be affected if I am also running my spillover while I am running the pump?

Thank you,

John
 
Hi,
I am currently in the process of my SLAM. Will my readings be affected if I am also running my spillover while I am running the pump?

Thank you,

John
John,
I think it's actually good since this ensures you circulate SLAM level FC so no algae hangs out in there. The spillover will increase your pH slightly but that's not an issue. You can adjust after the SLAM.

Chris
 
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