How to time/schedule pump/SWG

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macscom5

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Sep 9, 2009
9
First let me say thanks for TTP. I've had the pool running since June and I've learned tons from this forum.

I have a digital timer for my pump (two speed) and SWG and want to know if I'm running it correctly. I have been running the following schedule:

Start 8 a.m.
Run 1 hour on high w/ SWG running 1 hour at 100%
Run 4 more hours on low (w/o SWG)

Repeat the cycle starting at 2 p.m.

The pool is staying clean and clear, but I have had some trouble getting the FC levels dialed in. I realized today (now with a TF-100 and reading the Forum) that the FC is high and should be about 4. I have adjusted the SWG to run 40 minute twice a day and I will test to see if that levels it out at 4.

Is this schedule a good plan or does someone have better info? Also, I will need to modify the schedule to run on high about 5 hours mid-day so I can run the solar shortly. Does this sound about right?

Today's test results:
FC 6.5
TC 6.5
PH 7.5
TA 80
CYA 60

I realize the CYA is at the bottom of the range I will need to boost that soon.
 
macscom5 said:
Is this schedule a good plan or does someone have better info? Also, I will need to modify the schedule to run on high about 5 hours mid-day so I can run the solar shortly. Does this sound about right?
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Hi Scott,

I don't see Calcium Hardness ppm listed in your test results; you'll probably want to test for that at the same time as CYA.

Not sure there is an "ideal" plan or schedule since every pool is different, but you might want to consider dialing back your SWG a bit, experimenting until you can figure out how to regulate the chlorine. I have found that I'm always tweaking it in order to adjust for temperature, pH swings, usage (bather load) and, most important in my case, the amount of time the solar cover is on the pool.

Greg
 
macscom5 said:
I have been told that you can get longer life from the SWG cell by running it less time at 100%. Is this true?
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I don't know if this is true, but it's widely believed. Fewer service hours = extended product life, and so forth.

But is it wise to run the cell at 100%? Not sure if this aligns with common sense. It probably depends on whether the mechanism is running within its normal operational boundaries. My conjecture: If a particular model SWG was designed or documented to have a MTBF of 25000 hours at a 70% setting with normal water chemistry, etc and a MTBF of 5000 hours at a (theoretical) setting of 120%, then running at 100% would provide an average life between these two figures (5000-25000 duty hours.) Anecdotally, I find that dialing down the rheostats to 50% or less on my incandescent fixtures, ensures that these bulbs last years and years (decades?)

:sunny:

Hmmm... I'm rethinking this. If the SWG is a binary operation (on or off, with no type of inbetween performance) then a 100% setting just means it's ON all the time. My analogy using a rheostat and incandescent light doesn't work. Perhaps someone on this forum with industry knowledge could provide a more definitive answer.


edited by Greg 9/18/09 6:15pm Pacific Daylight Time
 
My understanding of ECG is that they HAVE to operate at 100% POWER input(watts), and if there is a setting percentage involved, it only applies to TIME of operation, ie.. 5 minutes out of every 10 is a 50% power level but the cell gets 100% of rated wattage for 5 minutes, 0 for 5. I think that ACTUAL power usage by the ECG system will be lower with 100% power setting, as it can sleep the rest of the time, whereas one that cycles on-off several times will use more energy(probably not enough to measure, though) as it checks operational procedures each cycle(salt level, flow, temperature,etc..) The programming for the user(and help calls to the manufacturer) is easier with only a % setting.

I didn't notice when you test, but I generally like to have the water "stirred" for at least one hour before taking a sample, and I like to get it when the chlorine level should be at its lowest, or after the sun is off of the pool. I then add my chlorine to maintain that lowest level ABOVE the recommended minimum level (with bleach, LC, or ECG.) If your solar will work on LOW speed, I would turn it ON as soon as it effective, run it as long as possible, collect water sample near sundown, operate ECG for required time(on HIGH pump speed, if required,) turn system OFF. Adding chlorine after the sun is off of the pool makes it easier to do overnight FC loss tests, if you ever run into algae(here's hoping you don't!) I have no experience with a 2-speed pump, but my understanding is that they use more then twice the amount of electricity on HIGH. The filter should not care what speed you use, and if you get good circulation and mixing on LOW, I would only use HIGH to vacuum/clean.
Best Wishes!
 
Thanks for the advice. The part about the SWG "cycling" to make the % seems to make sense. The SWG is running when the pump is on high - even though that is not required.

I have been testing between 4 and 5 p.m. That time is when I can consistently do it. The SWG is done for the day at that point and the pump is still running on low. There is another 1:45 minutes of sun right now when I test.

It is easy to keep the FC level high enough and I am always making sure I am on the high side (if I'm off) since there seem to be no negative side effects to being 1-2 ppm higher that ideal (please tell me if this is incorrect).

The solar requires high speed so I'm trying to figure out how long I need to run on high to get enough circulation w/o running my electric bill too high. Any help here?

Thanks,
 
macscom5 said:
It is easy to keep the FC level high enough and I am always making sure I am on the high side (if I'm off) since there seem to be no negative side effects to being 1-2 ppm higher that ideal (please tell me if this is incorrect).
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It is not incorrect. (Sorry, double negative.) :) If CYA=60-70 then a 5% minimum chlorine level is about 3.5 ppm; 1-2 ppm additional creates no issues that I'm aware of.

macscom5 said:
The solar requires high speed so I'm trying to figure out how long I need to run on high to get enough circulation w/o running my electric bill too high. Any help here?
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So, you've got three concerns.

  • One, getting enough circulation -- if you try to achieve at least 1 turnover (total nbr of gals in your pool, pumped/filtered in a 24hr day) you'll likely satisfy that criteria.

    Two, solar gain to provide sufficient heat for your pool. This is a matter of preference. If your circulation is adequate, schedule longer mid-day pumping if you want additional heating of the water. If you add 30 minutes mid-afternoon, offset that by 30 minutes less in the morning. Use a solar blanket on your pool when not swimming to maintain water temperature and, to the extent this succeeds, reduce your solar pumping time. Extensive use of a solar blanket will probably lead to an increase in chlorine due to continued SWG production and reduced UV exposure, so you may want to monitor this, dialing back the SWG if indicated.

    Three, curbing or reducing total operation time of pumps and other electrical equipment so as to minimize your utility costs. Would recommended a very methodical approach (read: slowly) in reducing pump and/or SWG operation until you arrive at a schedule that provides minimal circulation (~ 1 turnover) during swim season. Afterwards, divert from solar entirely and reduce your pump speed to lower setting. From late fall through spring (or when the pool water temperature drops below 60) you can probably get by on less than 1 turnover.

Mind you, some good people here will be uncomfortable with this. I run my main pump 2.5-3.0 hrs per day in the summer (which is 1 turnover for my pool), reducing this time to just 1 hour in the winter. (I need this hour for the pool sweeper to make its rounds.) Hope this helps to answer your questions.
 
Why not just set the SWCG at a lower percentage (say 50%) and let it cycle on and off during the pump cycle? As long as you have sufficient flow (most, if not all, SWCG's have flow switches and require a certain flow rate), you could be introducing chlorine gradually over the entire run time as opposed to one big "blast" for just an hour, which may or may not be enough.

I would be one that has a problem with polyvue's run time :shock: A pool that only runs for 1 to 3 hours a day is stagnant (eewww!) for 21+ hours a day! That is approaching a swamp to me (no offense, polyvue :-D !). I liken it to leaving a glass of water sitting on the counter for 20 hours and then coming back to it. I'm not going to drink that, and the idea of my pool sitting stagnant for that long kinda freaks me out too!

The cells are rated (10,000 hours on the IntelliFlo, for example) and do need replacement. I do not believe that they are capable of running at anything other than 100% when they are running though. It is just a cycle on/cycle off system. When your time is up, your time is up! Calcification of the cell makes it harder for the cell to work and will affect life expectancy as well.

Bruce
 
simicrintz said:
Why not just set the SWCG at a lower percentage (say 50%) and let it cycle on and off during the pump cycle?
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simicrintz says succinctly in one sentence would I tried to convey in a feature-length article

simicrintz said:
A pool that only runs for 1 to 3 hours a day is stagnant (eewww!) for 21+ hours a day! That is approaching a swamp to me (no offense, polyvue !). I liken it to leaving a glass of water sitting on the counter for 20 hours and then coming back to it. I'm not going to drink that, and the idea of my pool sitting stagnant for that long kinda freaks me out too!
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Grrrr!!! :grrrr: Whose pool are you calling a Swamp?

(It's a swamp that's usually covered, and whose entire volume is turned over daily via a strong pump through a skimmer with a clean sock and an oversized cartridge filter that doesn't really need its once-a-year cleaning. The high point of my summer was when I had thought, wrongly, that I had chloramines in excess of ~0.2 ppm and shocked the water. No algae. Ever. So, more like a 20 hours old glass of water covered with plastic wrap sitting on the counter, which is then emptied into a filter and... swum in.)
 

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Thanks for all the advice. Here is what I'm doing now that seems to be working well.

I added stabilizer to get the CYA to 70. With SWG running 60% for 1:40 minutes, twice a day the FC stablized at 4.5 (measured 4 pm after SWG is done for the day). This also seems to have lowered my acid demand :-D

Now that I've got that good, I have had to change over to fall schedule to keep the water temp up using my solar (still too lazy to put the cover on).

That looks like 2 cycles per day (one at 10:10 and one at 12:50). Each cycles is 2:30 min on high w/ 1:20 of SWG at 60%. Temp is holding at 84 and FC at 4.5. :lol:

I would not have survived new pool ownership without this forum and my TF-100 test kit. Thanks again.

Scott
 
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