May day, water level is going down fast

[lostcause]

Hi all, here's the bottom line-up front:
Inground pool (20 years old), vinyl liner, leaking inches per day, pump is off, water level at this point is around a foot.
What I have done:
Prior to the water level being as low as it is, I tried the dye tests around the likely suspects (skimmers/steps) to no resolve. I let the water drop to below the skimmers, then it went below them- and I thought surely it was a problem near the steps- but it's kept dropping. Currently water level in shallow end is below steps. Thinking that the culprit has to be the main drain.
NOTE: I do know I need to fill the pool so the liner doesn't collapse. I plan on doing that, but I want to plug up some things but I don't know where to start. I even tried to put a piece of plastic over the main drain thinking that if the leak was there it would suction to the plastic (didn't work, plastic never suctioned). The other thing is the suction line (not sure my term is correct, but it is the pipe for the water when it's backwashed) has water running out of it constantly. It has never stopped, and there is still running water out of it as I type, but just a to a lesser pressure than when the pool had more water in it. I am lost at this point and don't know how to start- hiring a leak detection person here costs a minimum of $400. I'm guessing it's a main drain issue, but how do I get water to stay in the pool until any type of hope for repair can be done?
Other info:
No water has ever been seen around the pump. The concrete around the pool (stones and concrete type patio) is cracked significantly. Not sure if that is from some kind of underground leak or just that there has been a lot of settling on the property (it is on a hill).

Any takers on this riddle? Thanks to anyone who wants to take a stab at it- I am too broke to hire someone $400!

 

[JohnT]

Your waste line shouldn't have water coming out, and if it is, that may be your whole problem.

It probably indicates that your spider gasket is bad in your multiport. And easy repair. To check it out, put a test plug like this into the end of the line to see if the water level in the pool stabilizes.

 

[lostcause]

First, thank you SO MUCH for that recommendation- I just took off the multiport and the spider gasket is completely fubar!! It's shredded and also the spring is toast, as well (rust and corrosion). I am completely grateful for your suggestion- YOU ROCK!!!!

Second, if I plan on replacing the entire component- the pressure gauge hasn't worked all summer, either- would I just need to purchase a replacement control valve and is there any other consideration for doing this? Meaning, is it possible for a rookie pool custodian to execute this task?

THANK YOU THANK YOU THANK YOU AGAIN, JOHN T!!!!!

This has been the most helpful site- I have been searching all summer for leads on correcting this.

 

[UnderWaterVanya]

Second, if I plan on replacing the entire component- the pressure gauge hasn't worked all summer, either- would I just need to purchase a replacement control valve and is there any other consideration for doing this? Meaning, is it possible for a rookie pool custodian to execute this task?

CHeck YouTube - several video's on replacing multiports - maybe you can try with your specific brand info in the search and find something really close to give you a preview and let you decide if it's over or under your skill level.

Here is a fairly generic video that isn't the best but might give you an idea of what you are likely to need to do.

[youtube:17q49yff]XVr5d_mpKAI[/youtube:17q49yff]

 

[Qwaxalot]

First, thank you SO MUCH for that recommendation- I just took off the multiport and the spider gasket is completely fubar!! It's shredded and also the spring is toast, as well (rust and corrosion). I am completely grateful for your suggestion- YOU ROCK!!!!

Second, if I plan on replacing the entire component- the pressure gauge hasn't worked all summer, either- would I just need to purchase a replacement control valve and is there any other consideration for doing this? Meaning, is it possible for a rookie pool custodian to execute this task?

THANK YOU THANK YOU THANK YOU AGAIN, JOHN T!!!!!

This has been the most helpful site- I have been searching all summer for leads on correcting this.

As long as the framework that holds the spider gasket is intact, and you can get the old gasket out cleanly; you should be able to replace just the top part of the multiport.

You might even be able to buy a rebuild kit and replace the gaskets, the spring and the wear plates.

 

[lostcause]

Thanks! I found a top mount and am going to replace it when it arrives. Thanks again, all!