# Thread: Perplexed on actual capacity

1. ## Perplexed on actual capacity

I had found old paper work stating my pool was 16,500 gallons.

When I did the fresh fill after the new liner was installed a week ago, I
first did a 5 gallon bucket test. It filled the bucket in 25 seconds (good pressure!)

With that math I determined (with the fill time) the pool was actually closer to 13,000 gallons.

one thing I know for sure, when I added the very first gallon of 8.25% bleach, it raised FC exactly 4.5 ppm.
I added another gallon when it got time to add more and again 4.5 ppm.

According to pool math that would make the pool 19,000 gallons....I find that hard to believe.

I put in an email to plastimayd to see if they can tell me the precise volume since it was
a custom made liner. The installer wasn't sure they could tell me which seems odd.

2. ## Re: Perplexed on actual capacity

Originally Posted by borjis
I had found old paper work stating my pool was 16,500 gallons.

When I did the fresh fill after the new liner was installed a week ago, I
first did a 5 gallon bucket test. It filled the bucket in 25 seconds (good pressure!)

With that math I determined (with the fill time) the pool was actually closer to 13,000 gallons.

one thing I know for sure, when I added the very first gallon of 8.25% bleach, it raised FC exactly 4.5 ppm.
I added another gallon when it got time to add more and again 4.5 ppm.

According to pool math that would make the pool 19,000 gallons....I find that hard to believe.

I put in an email to plastimayd to see if they can tell me the precise volume since it was
a custom made liner. The installer wasn't sure they could tell me which seems odd.

When you did the bucket test, how long was the hose for the bucket test? When you filled the pool, how long was the hose? Is this city water or water from a well?

I have a well and the 50' hose near the tank has a lot of pressure, probably 15 gallons a minute. As water travels to other parts of the yard, the pressure drops, because the length of water travel is sometimes 200'. Maybe I am mistaken.

Once I called Target about the bleach off the shelf and they called me back (great customer service). They claim that the bleach concentration is more than 8.25% and has a shelf life of 6 months, so it is produced at a stronger concentration based on the amount of time that the department store sells it (Maybe true).

In your case, maybe it is a combination of bleach % that is higher than labeled, calculations off on the time to fill up the pool, and some testing error (which happens). I know the well stops at 60 psi and starts at 40 psi. There is more pressure as the pump is raising and filling the bladder, and less as the water is coming out (if this makes sense). Of course, I use city water for filling the pool. So maybe the pressure changes throughout the hour and filling a large pool could cause miscalculations.

3. ## Re: Perplexed on actual capacity

What's the length, width and avg. depth of the pool? There are a number of websites that will get you to with a relatively adequate SWAG (Silly Wild A__ Guess) and you can adjust your chemicals from there.

For instance, I have a 17' x 35' Grecian shaped IG pool. When I enter in the rough numbers (not considering the cut off corners), Poolmath tells me my capacity is 25K gallons. However, because my pool is Grecian shaped, the corners are cut off. I found a site that calculated at 20,900 gallons, which is close enough for government work.

Use PoolMath to confirm:
2. While pump is running, Use PoolMath to calculate how much fresh liquid chlorine will get you to a predicted level (use a measuring cup for accuracy).
3. Wait a half hour.
4. Re-test Chlorine.
5. Compare actual to expected.

Remember also that if you are using a ruler or tape, you need to measure to the water level, not the coping.

4. ## Re: Perplexed on actual capacity

I'd go by what "fresh" bleach at a certain percentage raises the FC by and be done with it according to poolmath. It's on target.

5. ## Re: Perplexed on actual capacity

Here's a method using TA to measure the pool volume by long time TFP member and plaster expert, onBalance.

6. ## Re: Perplexed on actual capacity

Originally Posted by Catanzaro
When you did the bucket test, how long was the hose for the bucket test? When you filled the pool, how long was the hose? Is this city water or water from a well?
50 foot hose

same hose for filling

city water

I did notice when adding chemicals that with pool math set for 13,000, half of what was called for actually got it to the correct point.

for some dumb reason I added the full amount of acid (PH was 7.8) and after testing it had gone to 7.2 instead of the needed 7.5

The pool is 3.5 ft shallow to 7 ft deep. But the walls go down from the tile line at a rather steep angle instead of straight down in the deep end.
The installer called it a free form oval and was the reason a custom one had to be made.

Plastimayd got back to me and said their design software doesn't calculate volume which seems peculiar.

Anyone seen that episode of Breaking Bad when they pump out the train car/tank? That gallon gauge would've been handy when filling the pool lol.

7. ## Perplexed on actual capacity

Originally Posted by borjis

Anyone seen that episode of Breaking Bad when they pump out the train car/tank? That gallon gauge would've been handy when filling the pool lol.
Yes. Loved that show. Watched every episode and season on Amazon.

The cheap flow meters that you hang on house spigots usually top out at 500-1000gal and then reset. I've seen electronic flow meters that measure instantaneous rate and will display up to 9999 gallons and then go back to 0000 but increment a special mark for every 10k gallons. Problem is though flow meters are typically hundreds of dollars.

8. ## Re: Perplexed on actual capacity

I would bet that the flow of your city water varies based on all of the other proples use in your local area.

Use math. It never lies.

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