# Thread: I'm no math wizard

1. ## I'm no math wizard

Wonder if anybody would care to tackle a math problem for me? I can do math, but not Algebra....LOL. My SWG is capable of putting out 1.06 of Chlorine Gas a day, and according to PoolMath, I need 6 ounces to push my FC up 3 points. What would be the best % to run SWG and how long on the pump? My target is 6, and my CYA is 70. Any takers??? Thanks!!!

2. ## Re: I'm no math wizard

Put 1.06 pounds = 17 oz of chlorine gas in the "Effects of Adding Chemicals" section of PoolMath. That is how many ppm of FC it would add running at 100% for 24 hours. The most energy efficient method would be to run at 100% for the shortest pump run time.

So take your desired (3ppm) / (# ppm it can generate in 24 hours) * 24 hours = # hours at 100% to generate 3ppm.

3. ## Re: I'm no math wizard

1.06lbs/day * 16oz/lb * (1/24hrs) = 0.7 oz/hr

6oz / 0.7 oz/hr = 8.5 hours

That's at 100% output on your SWG and represents the absolute minimum pump run time. If you decrease your % output, then you need to run your pump longer. At 50% SWG output, your min pump runtime would be 17 hours.

What are your electric rates like and what kind of pump do you have?

4. ## Re: I'm no math wizard

Originally Posted by JoyfulNoise
1.06lbs/day * 16oz/lb * (1/24hrs) = 0.7 oz/hr

6oz / 0.7 oz/hr = 8.5 hours

That's at 100% output on your SWG and represents the absolute minimum pump run time. If you decrease your % output, then you need to run your pump longer. At 50% SWG output, your min pump runtime would be 17 hours.

What are your electric rates like and what kind of pump do you have?
Thanks for the VERY quick response guys! I have a Splash Pool 2 speed pump, and our electric rates are very cheap (as far as cheap can be for electric)

5. ## Re: I'm no math wizard

Does your SWG work on low speed (sufficient flow rate)? If so, then just run it for 9 hrs per day at 100% output and see where it goes.

6. ## Re: I'm no math wizard

Yes it will run SWG on low pump setting. Should I break up the run times, like 3- 3hour runs, or run it straight through one time a day in your opinion? I wouldn't have thought that I would have to run it that long at 100% to achieve 3, but that is why I asked. Thanks Matt!

7. ## Re: I'm no math wizard

Breaking it up can be beneficial to skimming the pool.

8. ## I'm no math wizard

Most people would say that you should chlorinate during high sun hours. You can certainly add an extra cycle when the sun goes down but a clean pool has very little overnight loss. I would not split the schedule beyond two divisions. I do all my chlorination during the day and then run a cleaner and slow-skim cycle at night.

9. ## Re: I'm no math wizard

OK, Thanks Jason!

10. ## Re: I'm no math wizard

Originally Posted by JoyfulNoise
Most people would say that you should chlorinate during high sun hours. You can certainly add an extra cycle when the sun goes down but a clean pool has very little overnight loss. I would not split the schedule beyond two divisions. I do all my chlorination during the day and then run a cleaner and slow-skim cycle at night.
I am waiting on my electrician to install a timer, so that will make it easier. My SWG compensates for water temp, so the output is higher as the temperature goes up. I don't know when the timer is installed if I can make the SWG turn off, and just let the pump run at night for skimming purposes. I need to be finding that out.

11. ## Re: I'm no math wizard

You need to put the SWG on a separate timer where the power to that timer is slaved to the pump timer. That way, the SWG can not power up unless the pump is running. Unfortunately this is not easy to do with simple mechanical timers which is why automation panels work a little better for scheduling. Intermatic sells some entry level digital control systems that can control a few circuits at once. It's a big step up from the old-school buzzing mechanical timers with set screw adjusters.

12. ## Re: I'm no math wizard

Would you happen to have a part number for one of those digital timers? Would I need one or two digital timers this way? I am looking at amazon now, and WOW, there are a lot of them!!

13. ## Re: I'm no math wizard

Something like this -

MultiWave Wireless Control System

14. ## Re: I'm no math wizard

Thank you! I will look into these

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