I've never seen one of these before and was hoping someone could shed some light on it. The pool is about 25 years old - 13,500 gallons with a Triton II sand filter, AO Smith 2hp motor and Jandy Lite2 heater.
I always wondered what it was, until I turned on the spa jets one day and it started spewing water (see video). It has never done this in the past.
The spa has several small jets and one large inlet w/ a grate near the bottom. I believe the large inlet is clogged because the smaller jets still produce a good stream. The last time I turned the jets on, the spa turned green and brown almost immediately. The next time I tried turning them on is when the standpipe erupted. There doesn't seem to be a noticeable change in pressure.
I guess my question is, are these pipes common? and whats the best way to check for a clog. I've got one of those rubber bladders that attach to the hose. Or would a snake from Home Depot be better to start with?