Pool Opening Problems.

Pump is 2", but you can see the 2x1.5 insert adapters in the inlet & outlet.

Oops. Not quite.

The valve is a 1.5" valve with 2" fittings over the valve -- that would reduce suction flow loss on those segments a lot. Pipe from valve to pump is also 2". But, pipe from pump to filter is 1.5".

Sorry.

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Originally Posted by PoolDoc

Make 'em do pool problems . . . !

Concentrations, ratios, flow rates, complex volume calculations (liner pools are easy, because they are all straight sides or radius curves, so bright middle school students possess the basic black-box tools to do the calcs), and so on.

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Actually, I do. In the past couple of weeks, we have been doing some geometry. They have calculated the circumference of my pool, area of my pool floor, surface area of my pool (cylinder), etc. They all wanted to know if they could come over and swim when school is out. Uh............ I don't think all 140 of y'all are gonna fit in my pool!!

Great!

But what about volume, in both SI and US. And weight! Have a bag of M&M's and give it to the person who can best estimate the volume in 60 seconds.

And flow rate, in GPM, LPM and pounds per hour.

And, from the weight of sand in your filter, the average grain size (0.50mm), and the mass density of quartz, and an assumption of a grain shaped like an equilateral 4-sided pyramid (doubled) . . . calculate the number of sand particles in your filter!

Oh boy, Ben. You're gonna be in big trouble! Giving M&Ms is a big NO-NO! We can't give any food out for any reason in our district. No pieces of candy for a reward, no pizza parties for rewards. You can't even do any lessons with actual food. No cooking anything when we study fractions, etc. We might all get fat from those 13 M&Ms in the snack size bag!

Well, offer them a bag of all-natural and extra-healthy crickets instead. That will probably motivate the boys, anyhow . . . especially if you give out the crickets in the first class of the day. :o

PS. Walmart sells them, at least around here.

Just to add my two cents:
In case you haven't figured it out, for now pay no attention to T/A or CH. Don't add any baking soda.

For whatever reason your pH running a little low, in the 7.2 range isn't a problem. Don't "fix" it. Chlorine is actually more effective at lower pH levels and 7.2 is safe for vinyl and safe for swimming.

Carl

Suction piping is 2" from the pool. Dual skimmers, one on the near side and one on the far. Pump is at ground level, no more than 3' from the pool level to the pump, probably less than 2' total. Approximately 20-30 ft between the near skimmer and the pump. Filter pressure is ~20 psi clean and I normally backwash about ~28 psi.

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Originally Posted by mas985

Sorry, I was being a little lazy and not running full head calcs. I thought you were interested in an upper limit. But from the picture, it looks like the suction pipe is 2". So if you want full head calcs I need some additional information. If you have already given please post again so I have everything together:

Pump elevation relative to the water level (changes meaning of filter pressure)

Also, I don't remember reading the length of the suction runs. So how long are these and is the diameter 2"?

Filter pressure is 20 PSI correct?

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Originally Posted by TheGoose

Pump is at ground level, no more than 3' from the pool level to the pump, probably less than 2' total.

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This sentence is not making sense to me. Is your pump 3' or 2' above the water line (vertical distance)?

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Originally Posted by PoolDoc

Well, offer them a bag of all-natural and extra-healthy crickets instead.

PS. Walmart sells them, at least around here.

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And YOU buy these, I presume?

Sorry. The vertical distance from the water level to the pump suction. The pump is on a small slab, the pipe rises out of the ground about 12" or so, add in whatever the water level is below that, I would say probably a 2' suction lift. I haven't measured it, but it's pretty minor.

Thanks for all the replies.