SWG percentage

[mrm1682]

New pool build and water has been nice and clear and balanced pretty well so far. One thing I don’t have a feel for yet is percentage to run my SWG at. I had it at 50% like the PB told me but dialed it back to 40% and FC has been pretty good. Whenever there’s more use and FC dips down I bump the percentage back up. What confuses me though is that poolmath app tells me something like to run the pump for 3 hrs at 50% to get my FC up. My pump is on for 12 hrs a day so am I technically making too much FC? Should it eventually be a set it and forget it kind of deal with a SWG?

 

[shwn2405]

I check mine almost every other day to make sure it is operating correctly. The hayward swg lets you check the water temp as well. So i check the temp before i get in and also see that the cell is working correctly. Then when i do my FC test i might change my setting on the cell. I run my VS pump 24/7 which cost $15 a month, Then adjust my setting between 20-30%. Keep my FC at 5-7ish is my goal. I take pride in having a perfectly operating pool. That being said, If i went on vaca i wouldn't worry one bit about it running correctly. Just play with the settings and you'll figure it out.

 

[Texas Splash]

The SWG is designed to "hold" an established FC level as opposed to making large gains. Sometimes you can boost or increase the output, but when you expect a large bathers load it's okay to just add a little liquid chlorine. As for PoolMath, it helps guide you through the options of total FC produced, output, or run time to show you various ways to reach your FC goal. But in the end it's up to you how you get there. Keep in mind that with the exception of a large pool party, we don't like to use more than about 4 ppm of FC in 24 hrs. If you think your pool is going through more FC than 4 ppm in on day, it's time to run an Overnight Chlorine Loss Test, and if you pass, then increase the CYA a bit if it's below 70. Hope that helps.

 

[setsailsoon]

m,

I think you may be falling into the same trap as I did when I first started my swg. "If you try to micro-manage your FC level with swg it will drive you nuts" in the famous words of " @Jimrahbe . After you do what Pat advises to make sure you have no algae here is what I did and it worked like a charm to dial in my swg settings :

• Adjust your FC level to the high end of your target range with liquid chlorine each night until you get the % power adjusted with this procedure
• Adjust your pump runtime so it adequately skims and performs the aesthetic functions like spillway and water features for your pool
• Then use Pool Math to get the % power setting for your model swg and pool size for your desired ppm production. If you're not sure what you are consuming start at 3 ppm. Let it run a day or two.
• Test FC frequently and if you find it is trending up above the upper target reduce the % power 5%. Do the opposite if it's trending down.
• Withing a couple days you'll have the settings such that you cycle in a range of FC with no additional adjustments. The key is to stay in a range of about 3 ppm not a fixed ppm level. Run 1-2 ppm above target if needed. If you run on the ragged edge at the low end you risk dropping too low and having algae. If you run a little high it will never be a problem. Remember it's always safe to swim up to SLAM level and you're way below that with this procedure.
• If you can't achieve the desired chlorine production with the pump runtime then run your pump additional time at minimum speed to make the swg work. This is usually around 1500 rpm but each system is slightly different so make sure you do a little trial and error to be sure the swg runs. So long as you have the minimum speed you will make the same amount of chlorine as at high speed. Eventually you will have to run the pump longer and longer as the cell deteriorates. You can clean the cell at least a few times before you'll need to replace it. This is the main reason it's always good to size the cell at least 2x the pool volume. Plus incremental capacity is much cheaper than replacement cost.

Using this procedure I was able to "tune" my swg in a couple days. My pool ran year-round and all I had to do is adjust run time a couple of time each year. My FC was 5-8 ppm year round too. Power stayed at 40% all the way into my 3rd year when I sold the house.

I hope this is helpful.

Chris

 

[Jimrahbe]

Should it eventually be a set it and forget it kind of deal with a SWG?

1682,

It will never be a "set and forget" deal.. At best it will be an "I can ignore you for a while" kind of deal...

SWCG's have no brain. You have to be the SWCG's brain and tell it what to do by setting the pump run time and the cell output percentage. You need to routinely test and then adjust what the cell is doing. As you "learn" what your pool needs, the easier it will become and the less often you will have to test.

We can help, but you need to help us.. We need the following info...

What is the size of your pool in gallons?
What is your CYA level?
What specific salt system do you have, including the size of the cell?
What kind of pump do your have, Single speed, 2-speed or variable speed?

If you give us that info we can get you pointed in the right direction..

Another thing that I suggest is that you try to keep your FC at your Target level in the saltwater section of this chart... FC/CYA Levels

Do not try to stay between the minimum and the target.. Let the FC stay at your target or higher.

Thanks,

Jim R.

 

[mrm1682]

Thanks for the tips. I’m still getting used to balancing things and I always take baby steps in adding/adjusting so I don’t overshoot.

My CYA has drifted down to 50 and pH is up near 8 so I’m going to adjust those first then deal with getting my chlorine right.

 

[setsailsoon]

If it was me with these numbers, I'd make sure FC is always at or above target first. Then pH the same day, then CYA. Last thing you want is an algae problem when you're learning your new pool.

 

[mrm1682]

FC is always right around target but it’s fluctuated a bit. That’s why I’m balancing pH and CYA first then I would think that FC would be more steady.

 

[ajw22]

FC is always right around target but it’s fluctuated a bit. That’s why I’m balancing pH and CYA first then I would think that FC would be more steady.

How often are you testing?

FC does not stay steady. Expecting FC to stay steady is an exercise in frustration.

FC consumption varies with the weather. If you have a few cloudy days your SWG will generate FC steady but your FC will rise because the suns UV is not burning off the FC.

Have a few blazing sunny days and more FC will be consumed by the sun.

So do you set your SWG generation for steady FC on cloudy says or sunny days? If you tinker with it back and forth you will never win.

I run my FC about 2 ppm above target. You have a wide range of safe FC levels between target and your SLAM FC level. Just let your FC vary within the zone.

Then you have the changing sun angle during the year so your FC consumption changes with the seasons.

You should not need to adjust your SWG output more then once a month or so once you learn your pools cycles.

 

[setsailsoon]

FC is always right around target but it’s fluctuated a bit. That’s why I’m balancing pH and CYA first then I would think that FC would be more steady.

Then that's fine, I just couldn't tell that from your post. So long as it's fluctuating above minimum target (not absolute minimum) for your CYA you are OK. As several experts have pointed out FC will fluctuate. That's normal even without a salt pool. FC and pH are always monitored frequently since they can often change quickly if something is going wrong. Once you get your swg lined out and FC cycling in a safe range you're gonna see how nice it is to have an swg. Once I got it lined out I still monitored it but only rarely had to adjust anything. Ph was the only thing I adjusted and even that became monthly after I added borates (I would not mess with borates until you get very comfortable with maintaining your pool). CYA never drops suddenly so it's rarely an urgent thing. Most often in my case it would only drop quicker when we had massive rains for a couple days. Dumping pool water caused by lots of rain has a surprising impact on CYA and salt that can sneak up on you. Even in this case it's not an urgent matter unless it was neglected for months or so.

I hope this helps.

Chris

 

[mrm1682]

When I say steady I mean my FC has been between 3.5-5. CYA about 6 weeks ago was essentially 0 so got it to 60 then stopped to let it settle out. I was testing FC once a week back then but changed to 3 times a week at the advice of others here since it was a new pool. Like I said I haven’t really been adjusting SWG output at all really and just basically left it at 50% most of the time like the PB told me but I’ve been wanting to get it dialed in a bit better. Might not need to though since pool season will be over in about 6 weeks.