Necessary to Run Pump in Daytime?

[thomearl]

My local pool supply told me that it's best to run the pump in the daytime to really prevent algae outbreaks. Want to know if this is accurate, or is running it from 7pm to 5am ok? I'm currently running at night to take advantage of the best electricity rates. My hope is that running it in the day only applies if you're following the Pool Store method, but if I'm following the TFP method, perhaps night time runs are ok.

 

[pooldv]

It is fine to run at night, and you probably don't need to run as long as you are. 4-6 hours is probably enough unless your SWG needs the extra runtime. Just make sure there is enough chlorine in the pool so that it never drops below target level for your CYA, Chlorine CYA Chart. Dropping below minimum leaves your pool unsanitized and algae will grow.

 

[Divin Dave]

Really, it just depends on how much debris gets in the pool that needs to be skimmed during the day.

Chemically speaking, running day or night really doesnt make any difference unless you are using Trichlor Pucks in the skimmer.

The pool store method of using pucks in the skimmer would require the pump to run, so the pucks can dissolve and slllloooowwwllllyyyyy add FC to the pool water.
I can imagine this would be best done in the day to replenish what gets burned off by UV.

Using TFP method, as long as your FC is good, then run the pump whenever you want to.

There are quite a few folks on TFP that run their pump less than 2 hours a day, and water is perfectly fine.

 

[isriam]

I'm running mine during the day because I was losing so much fc. I wanted to see if it made any difference.

 

[woodyp]

I'll go yo one better. If you have a timer, split up your run times. Some in day, some at night to keep chemicals mixed, It ain't all JUST about keeping the top skimmed.

 

[pooldv]

If you are losing too much chlorine to sunlight during the day raise CYA to 40 or even 50 ppm to help with that.

 

[woodyp]

I'll go yo one better. If you have a timer, split up your run times. Some in day, some at night to keep chemicals mixed, It ain't all JUST about keeping the top skimmed.

After backing up and doing a bit of research..........it appears that chemicals------once mixed---------STAY mixed-----and don't settle back out or separate out as I had assumed.
<<<<........Spanks self.

 

[epro05]

Doesn't UV from the sun degrade FC at the surface more than at lower depths. I believe advice on this forum is to take water samples for testing at least 1 foot below the surface.

 

[domct203]

After backing up and doing a bit of research..........it appears that chemicals------once mixed---------STAY mixed-----and don't settle back out or separate out as I had assumed.
<<<<........Spanks self.

To me it seems that I get more consistent (& predictable) FC readings if I sample when the pool is circulating 30 min or so prior.

I run my pump/filter in cycles throughout the day. The bulk of my filtering is done from 10:45am-2:15pm & 2:45pm-6:15pm. My thinking is the 1/2 hour break would give the motor a rest.

Overnight I circulate a few hour blocks to keep the water moving under the solar blanket (11pm-midnight, 2am-3am & 5am-6am).

Probably overkill, I know, but the pool is clean

Dom

 

[isriam]

Honestly I'd think if you run your pool filter at night, you could have all or chlorine evaporate/leave during the day, so you could have a few hours in the evening where you have fc=0? i'd like to know some thoughts on this from the experts.

 

[pooldv]

It is definitely important to make enough chlorine overnight so there is enough FC by the end of the day to be at or above target level when the SWG turns on again.

 

[thomearl]

Thanks everyone.

 

[chem geek]

Doesn't UV from the sun degrade FC at the surface more than at lower depths. I believe advice on this forum is to take water samples for testing at least 1 foot below the surface.

As shown in the thread Water Absorption and Heating from Sunlight, one-fourth of the sun's energy is absorbed in the top 1" of water while another one-fourth (of the original total) is between that 1" and 3 feet. However, this uneven absorption is mostly from infrared since visible light penetrates more deeply without as much absorption and UV is absorbed even less, at least from water.

So with UV which is what breaks down chlorine the question is whether enough gets absorbed by the surface (say, by chlorine) so that lower depths are shielded. The answer is that if there is no CYA in the water then there is indeed a shielding effect from the breakdown of more chlorine near the surface, but with CYA in the water the amount of breakdown is much smaller so in effect the UV is not blocked, at least not that way. However, we do know that there is some sort of CYA (or chlorine bound to CYA) shielding effect of lower depths so you are right that without circulation the surface of the water would get depleted of chlorine more than lower depths.

So I would agree that at least some time during the day having circulation would be a good idea. Perhaps it would only need about an hour sometime after peak noontime sun, say running from 2-3 PM or something like that. Also, if one is going to take any measurements of pool water chemistry, one should run the pump first, probably for 30 minutes to get decent readings.