Quote Originally Posted by SunnyOptimism View Post
First off, the guy blowing pressurized CO2 into your lines is ... well .... i have no polite words for that. PVC piping is not meant to handle highly pressurized gases, it's designed for low pressure water flow. So anytime you "blow out" your lines, you should always start off with a garden hose and a FlowKing hose bladder. Using pressurized gas is a method of last resort and the person doing that should be experienced with it.

With the above said, I do tend to agree with the pool companies you've contacted. If the leak were above ground and in a valve or fitting somewhere, you'd be able to see it, especially a water leak causing significant water loss in your pool volume. Chances are you have a fitting in an underground PVC line or somewhere near the pool that is leaking water when the pump is running and the system is at-pressure. It is totally plausible that zero water pressure (pump off) would not cause a leak but running the pump does. The thing leaking could easily self-seal at low pressure and then open up when the system is running. I've seen this happen a lot in other situations I have been in where there is pressurized water (I used to be an equipment engineer).

With all that said, I would definitely be getting quotes from leak detection companies. There are many such companies here in the southwest, and it's not a huge cost to have them come out and do a full inspection of the plumbing system. I've known people in my neck of the woods who have had leak detection done on their irrigation systems because their water bills were hundreds of dollars a month only to find that they had a broken 1/2" feeder line at 25psi shooting gallons of water out when the drip system was activated. The money saved in finding the leak more than paid for the service. As well, for you, even if they don't find anything, at least you have peace of mind that your pipes are good.

Sorry to hear about your troubles! You did the right the thing trying to clean out your own filter, I really think the guy that blew the CO2 into your lines screwed it up.
Thanks so much for your reply, very appreciated. This whole thing has been so weird, from start to finish. When the pool guy came out to unclog the clog, he may have used a bladder in the beginning, and I think that failed to dislodge it. Then he used a higher power force....and THAT also failed to unlodge it at the time. He said maybe some debris was hung up in a joint that made a sharp turn or something. He left and the next day I turned the Jandy valve in different ports, to sort of get the water flowing back and forth, and that was finally what unclogged it. I don't necessarily blame the pool guy for using his higher powered device, because he was really trying to get it unclogged, and ultimately, he never did (I did). Mine being an older pool, perhaps it couldn't take that type of blast and something has come unjointed in a pipe. (also, he didn't charge me for his efforts, he worked for a solid hour to try to get it unclogged and since he was unsuccessful, he was a decent person and didn't charge).

Unfortunately, thereafter it was a case of losing water which as you seem to also feel, it's probably an underground pipe. Whether his blowing out process caused it, who knows? I had felt so proud of myself to teach myself how to disassemble the filter, clean it and learn how to maintain it better throughout the year (we have a lot of pine needles hanging over the pool, so it gets a lot of debris). and then to have this domino effect with the clog at the very instant I turned the pump back on after cleaning the filter, (weird!), and then the water leakage/loss, has been really disheartening.

The pool guy I talked to this morning referred me to a leak detection guy and indicated it usually costs about $200 to do the basic detection or pressure testing. That seems to be about what most companies charge for a basic testing of lines in my area. I agree, it is peace of mind to at least narrow it down and find out if a pipe is leaking. Then take it from there. I hardly use the pool at all and almost feel like draining it at this point. Just spent $120 to have a gasket seal fixed on the pump where it was visually leaking (I wanted to take care of all visual leaks before anything else). If it's gonna end up costing a lot to dig up concrete or whatever might be needed, I may call it a day on this pool. But your advice is well taken, it's not that expensive to have the initial leak test of pipes done. Thanks again for your input! (I guess when some repair forums suggest a Jandy valve might be at fault, they mean if there is visible leakage from that area, not some interior flap or area that is losing water inside the valve that's not actually visible). I had been hoping a valve was at fault, but since there is no visible water leaking around the valve, I think that pretty much eliminates that hopeful possibility.