# Thread: Size of pool? Filter Run Time, Flow rates and oddities

1. ## Size of pool? Filter Run Time, Flow rates and oddities

The pool I am maintaining with BBB came with zero data. I'm trying to determine the volume - I started out thinking it was much larger than it is - each time I calculate things I get smaller results.

I am very sure it's about 16' wide. I used my 16' pole to check this. I'm pretty sure it's 32' long based on this. However I haven't measured it accurately with a tape measure. That part is easy and I'm going to do it today. (I've only had control of the pool since Thursday). The tricky part is the average depth. The pool is very shallow on the shallowest part - I think 3'. Then about 1/3 of the way towards the deep end it starts getting deeper roughly ending up at 5', then the last third of the pool it goes deeper still to about 5.75' which it maintains for about 1/5th of the pool surface then quickly sloping back up to the walls (about 4' deep before getting vertical. The sides in the middle and deep end slope as well. It's more noticed in the deep end.

I read somewhere here that I could use an oval pool to approximate this sloping side part. If I plug in an average depth of 4.5' and 16x32 oval I come up with about 15,400 gallons. Is that a good approximation? I'll keep watching how chemicals react and if I ever have to pump the system dry and refill I can use a flow meter to measure the exact fill - but in the meantime am I in a rational position to assume 16,000 gallons?

If I recall from reading here 20% +/- of the total is not too bad for a starting estimate of volume. My original estimate was 19200, then 18200, then 17200, and now 15,400... 16000 +/- 20% = 19200 - 12800; surely somewhere in there lies the true size - right?

On to the runtime question. The pool was already setup with a timer. The filter is set to run from 8am - 10pm every day. That's 14 hours a day. It's not clear if this is necessary or if this is just a swag someone took. How do I determine the flow rate - is there a meter for that that pool companies can use?

The pool has a main drain and a skimmer, and three returns - two on the recessed stairs and one on the side midway down the side opposite the skimmer. The skimmer is closer to the deep end. There is also a slide dumping to the deep end. The flow rate on the two returns on the stairs is very good. Both have "eyeball" diverters. The flow rate on the return on the side of the pool is anemic. There is no eyeball on this return but it looks like there should be. Since I Have to fix this anyway - what do you guys think of the rotating eyeballs? I have seen them advertised and they show them with a dye test and show how much more quickly chemicals are distributed in the pool. While that's not often a requirement - I wondered if there was any benefit to it.

The valves on the pool are weird. I have yet to figure out how to get any flow from the main drain - if I open valves too far I suck in air - if I leave them half open each they work fine. I need to replace one anyway due to broken off tabs so I'm planning to get a pool company involved for that.

2. ## Re: Size of pool? Filter Run Time, Flow rates and oddities

I have a 16' x 34' inground vinyl pool with an average depth of 4.5 ft. My pool is around 18,300 gallons.

3. ## Re: Size of pool? Filter Run Time, Flow rates and oddities

I get around 15,000 gallons, assuming the corners are reasonably close to square. Any guess around there is fine for now. If over time you find that the levels change more than you expect lower your size estimate. If over time you find that levels change less than you raise your size estimate.

I don't like the rotating eyeballs. You can always do just as well with a manually aimed eyeball and it is less likely to break.

The low flow rate on the main return sounds like something that needs more investigation. I suspect the valve controlling that return is stuck part way off, but who knows.

To figure out your ideal pump run time see the article in Pool School.

4. ## Re: Size of pool? Filter Run Time, Flow rates and oddities

Corners are rounded with a 3' radius.

I will watch chemistry and see how things go...

5. ## Re: Size of pool? Filter Run Time, Flow rates and oddities

Raised the chlorine to 14'ish, increased pump run time to 22 hours - water is clear! Something is still living CC's barely pink but still not zero... have not done OCLT yet due to time pressures.

6. ## Re: Size of pool? Filter Run Time, Flow rates and oddities

CC's are not an absolute indicator something is wrong with your pool. CC's of .5ppm should be treated as if the result was zero.

7. ## Re: Size of pool? Filter Run Time, Flow rates and oddities

Argh... Wish I knew that earlier. OK now I just need an OCLT result huh?

8. ## Re: Size of pool? Filter Run Time, Flow rates and oddities

Originally Posted by UnderWaterVanya
The pool I am maintaining with BBB came with zero data. I'm trying to determine the volume - I started out thinking it was much larger than it is - each time I calculate things I get smaller results.
Just thought I'd update this old thread.

16x32 seems correct. Volume seems to be 13,500 based on the chemistry.

Originally Posted by UnderWaterVanya
On to the runtime question. The pool was already setup with a timer. The filter is set to run from 8am - 10pm every day. That's 14 hours a day. It's not clear if this is necessary or if this is just a swag someone took.
My runtime now is about 7 hours a day. I could probably shorten it but at this point I'm doing 6 hours during full sun and then 1 hour late at night just to stir things.

Originally Posted by UnderWaterVanya
The pool has a main drain and a skimmer, and three returns - two on the recessed stairs and one on the side midway down the side opposite the skimmer. The skimmer is closer to the deep end. There is also a slide dumping to the deep end. The flow rate on the two returns on the stairs is very good. Both have "eyeball" diverters. The flow rate on the return on the side of the pool is anemic. There is no eyeball on this return but it looks like there should be.
I have since realized this was for a Polaris cleaner and was attached via a booster pump which has a restrictive 1" hose that drops flow. I have plans to replumb this for a Jandy style valve that allows for me to select either booster or filter without reducing the flow while filtering to improve the flow during normal pump operation.

Originally Posted by UnderWaterVanya
The valves on the pool are weird. I have yet to figure out how to get any flow from the main drain - if I open valves too far I suck in air - if I leave them half open each they work fine. I need to replace one anyway due to broken off tabs so I'm planning to get a pool company involved for that.
I'm not sure what I was doing wrong before but I tinkered with this again. I think I was turning them off not on. I have both valves wide open now. There is a small amount of suction felt at the main drain and the skimmer works normall. There used to be a small amount of air in the pump basket but with both valves wide open that problem has vanished. Interestingly the filter pressure has risen from 11psi to 13.5psi. I assume the restricted flow prevented this from happening before.

Suction lines are 1.5" each (one each from Main drain and Skimmer) and pump and filter are plumbed with 1.5" pipe. Two 1.5" return lines and one smaller (3/4"?) line branch off from the filter - one of these 1.5" lines splits to two eyeballs on the sides of the stairs and the other 1.5" is limited by a booster pump 1" fitting and is on the side of the pool.

In any case - progress is being made and I understand my pool much better than before.

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