Leak in Pressure Side -- What can fix it?

[NullQwerty]

Hey folks,

I'm losing often about 1 1/2 inches of water per night in my in-ground vinyl pool with the pump running. Here is what I have done to troubleshoot so far:
1) Replaced the seal assembly on my pump and no water leaks out of the pump now...but it didn't solve my water loss issue of the pool.
2) Turned equipment off and plugged all lines including the skimmer to confirm it was not a tear in my vinyl. Did not lose any water like this. (used bucket test here)
3) Same as "2" above, but left skimmer line open to confirm it was not the skimmer line. Again, no water loss.

However, with the lines open and the equipment running, I lose the 1 1/2 inches.

I don't have a drain line (just a skimmer and 2 returns), so my guess is, that it's in one of the return lines. Agree? I do have some minor water loss by the filter, but nothing that could account for this.

So, a couple questions:
1) Is it safe to have my multi-port valve use only one of the return lines to figure out which line has the leak? If so and if I find the line, is it fine to use just 1 return line for a season or 2 (in order to wait for when I'm ready to invest the money in tearing up the deck)? Obviously it won't have as good circulation or clean as well, but should I be fine?

2) Does this Fix-A-Leak stuff work and if not, is there anything that does (other than tearing up the pool deck) http://www.ecrater.com/product.php?pid=1878600

Thanks!!!

 

[spishex]

#1 depends on how your plumbing is set up and how you orient your returns in the water. A pic of your equipment would help with that. Some returns are probably going to share the same plumbing so it may be impossible to narrow it down to just one that way.

#2 Don't bother with that stuff.

Make sure you're not losing water through the waste line when the equipment is running. A bad spider gasket can cause a lot of water loss.

 

[NullQwerty]

Thanks for the response!

I attached a crude drawing because I'm not at the pool.

You can see how the two lines are separate all the way to the valve. I can set the valve to be on full on for either line, 1/2 for both, or off completely. So, I think I can diagnose it this way, and should be able to leave it on this way. I just don't know if running only 1 return line would put too much pressure on it, and I also don't know if it would be so little circulation that my pool couldn't stay clean. What do you think?

Also, I don't have a waste line...just what you see.

Thanks!

 

[spishex]

Well, that makes it easier. You can run it at least to test the lines. Just for testing you might want to take the eyeball off the return line that's running, which will take a little pressure off. As for running the pool that way, you can do it but it isn't optimal. I used to take care of a pool years ago that had only one functioning return and we had to build a "T" for it with an eyeball on either side of it. That return was right in the middle of the pool so it was pretty effective that way.

Anyway, you can do it. You'll probably just find yourself having to brush much more often.

 

[NullQwerty]

Cool! Thanks!

So, I just set the valve to go to the shallow end only. I noticed when doing so however that the pressure on the filter (D.E. filter...kind with the fingers...has bump handle, no "true" backwash) goes from 14, which is normal, to 24 which is high. I felt the returns and I have decent flow coming from the shallow side and nothing from the deep side, as expected.

Should I be concerned about this pressure spike, or was this to be expected?

Thanks!

 

[spishex]

That's to be expected, and a lower flow-rate comes with it. Your tank can handle it but you might have to run the pump a bit longer.