Low Flow over Spa Spillover

I have an 8-year old pool, 12000 gal, with attached spa and spillover. After some re-plastering and re-attachment of spillover, our flow over the spillover is occasionally low. This is even after backwashing and with a well-functioning pump.

The interesting thing is that if I touch the front edge of the spillover, the water flow suddenly becomes more smooth and the flow becomes a normal "waterfall." There seems to be some kind of fluid dynamics involved indicated by the fact that there is a subtle and invisible interruption of smooth flow remedied by my physical disturbance.

Any thoughts about cause and, more importantly, a remedy?

Any thoughts? Nope, not without seeing photos and a complete schematic of your piping system.

I've posted this, and maybe someone, who has encountered the same problem, will see it and go, "Yes, that happened to me, and here's what the issue was" . . . and you will turn out to have the same issue.

Good luck!

. . . membership upgraded.