How long to run filter and SWG

[JazzMan2010]

First, i'm a new pool owner. Second, i think i've learned more about pools in two days on this site than the 2 months i've had it. I have a 18x36 in ground pool with a Polaris auto clear SWG. I purchased a house with the pool late last August and ran it until closing in late Sept. During that time i ran the SWG about 8-10 a day and the filter about 12 hours. Now that we are starting up and temps are lower my manual says i only need about 2-3 hours a day on the AutoClear. Does that sound right? Also, are there certain times of the day that's better to run it. As well, how long should my pump filter be running and are there better times of the day to run that. I know i'm asking a lot of questions and appreciate any reply to the whole or parts of my post.

Thanks.

[aylad]

Hi, and welcome to the forum and pool ownership!! Glad you're finding useful information around here--feel free to ask any questions you have. There are lots of folks with knowledge in lots of areas that are happy to help.

I can't answer all of your questions, and SWG is NOT my area of knowledge, but a general guideline is that you need to turn over the entire volume of your pool at least once daily. I have an 18 x 36 IG with a 1 hp pump and find that 6-7 hours is sufficient for my pool--but I usually just take the lazy way out and turn it on when I get up and off when I go to bed, so in reality it runs 10-12 hours during the summer. Your SWG needs to run enough so that you maintain at least 3-5 ppm of chlorine. Whether you can do that and then have it last throughout the day or whether you need to run it twice per day for shorter times will be up to you and the SWG experts around here, who I'm sure will be by soon to help answer.

I don't know where you are in the country, but I'm in Louisiana where it is very hot and very humid year round. By about mid July, my water temp is usually in the mid to high 90s, and when that happens I find that running my pump at night instead of during the day helps keep the water cooler. Otherwise, when you run the pump is pretty much your call.

Janet

[BigTallGuy]

I currently run my filter (and SWCG) for 6 hours per day. I have it come on at 8:00 p.m. and shut off at 2:00 a.m. I do this because the sun is down and the chlorine level builds up without having to fight the UV burn off, and it is reportedly cheaper to run your pool at night, but I am not convinced. I have approx. 11,500 Gallon pool. I know I could have it start at midnight, but I kinda want to be awake when the pump starts to make sure there aren't any problems.

If it is safe to assume that that the chlorine level will be highest at 2:00 a.m. when the pump shuts off, and lowest after sunset before the pump kicks on, then I would suggest you see what your chlorine level is after sunset. Yesterday, when I got home from work at 5:00 p.m., the Chlorine level was approx. 3 ppm. So I am thinking I could effectively cut back on the ON time.

Also, watch your pH level.

[Torontonian]

I have tried all different combinations but this is what is working best for me once getting the pool clear:

3 cycles of 4 hours each with Aqua Rite dial at 70% output:

8am to 12pm
4pm to 8pm
12am to 4am

We are on Time of Use rates in Ontario so this works out to:

4 hours at lowest price rate
6 hours at mid price rate
2 hours at highest price rate

This way the pump/swg are on for 4 hours and then off for 4 hours repeat...

[Phillbo]

I run mine from 9pm to 1am and then again from 5am to 9am. This is primarily due to 9pm to 9am being discounted (read- not gouged) electricity rates. I live in Az so 8 hours min is recommended in order to keep my chlorine level up.

[waterbear]

Pump run time and cell output percentage are inter related. For example a unit set at 10% and running for 1 hour (60 minutes) and a unit running at 100% for 6 minutes would generate the exact same amount of chlorine since both would have the cell on and producing chlorine for a total of 6 minutes. However, the first scenario is going to be more effective at filtering your pool.

So given this (and assuming your unit is NOT undersized for your pool) you first want to adjust your pump run time to provide proper filtration (usually a minimum of 6 hours and possibly as long as 12 hours, depending on your filter/ pump combination and the size of your pool). This can be one continuous run or broken into smaller runs. However, if you break it down find out what the reversal cycle time is for your SWG and make the smaller runs an even multiple of this timespan (for example, my Goldline unit reverses polarity once every 100 minutes, and Pool Pilot units have an adjustable reversal time that defaults to 4 hours, if memory serves me correctly.)

Once you have your pump run time squared away to provide proper filtration you then want to adjust the cell output to maintain the FC level at the desired level ,3-5 ppm FC works well with most SWG installations.

One mistake that many people make with SWGs is NOT having enough CYA in the water. With a SWG you want it at the manufacturers recommended MAXIMUM (usually 80 or 100 ppm depending on the brand). By keeping the CYA at the top of the range you can maintain the FC in the recommended 3-5 ppm (which seems to work out best for a SWG) with the minimum cell on time. This has the desired effect of minimizing the acid demand (pH rise) that is commonly seen with SWGs. ( I won't go into the chemistry behind it here but it is NOT what most people think. It is caused by the outgassing of carbon dioxide, which brings me to the next thing....lowering the TA.)

Finally, to further minimize the acid demand and give you better pH stability, lower the TA to 80 ppm or less and adjust the pH to 7.6. When the pH climbs to 7.8 add enough acid to drop it to 7.6 but not lower since the lower you drop the pH the faster it rises again (once again I won't go into the chemistry but it's because of outgassing of CO2).

One last thing that you can do that I would highly recommend is adding borates to 50 ppm. This does two things (it does more than two but these two have the biggest impact on your SWG operation)

1) it acts as an algaestat and effectively controls nascent algae blooms so you will have a reduced chlorine demand and can dial the output of your generator down even more and still maintain the same FC level. This has the effect of reducing your acid demand even more by causing less outgassing of CO2!
2) It introduces a secondary boric acid/borate pH buffer that works in conjunction with the normal bicarbonate/carbon dioxide buffer (we measure the bicarbonate part of this buffer with the TA test) that effectively "locks" the pH at around 7.6-7.7 for a longer time than without the borates.

I hope you find this useful and hope this has not confused you. If so just ask. Much of the actual chemistry that I alluded to can be found in the "china shop" section of the forum but realize that it is not for the weak of heart! (chemistry nerds tend to hang out there!)