Low flow at return jets / skimmer

[PoolDoc]

A suction leak would lead to low flow on backwash, too.

It really sounds like you have an obstruction down stream of the filter. Could you have crimped a pipe when you "replaced the floor"?

[Poddle]

A suction leak would lead to low flow on backwash, too.

Thanks - I just hoped my system didn't follow the laws of physics....

It really sounds like you have an obstruction down stream of the filter. Could you have crimped a pipe when you "replaced the floor"?

Sadly, no. All the pipe work is above the floor and was disconnected during this process. Downstream of the filter I have a gas heater, solar panels and used to have a chlorinator. I can bypass the solar panels so I can rule them out as a cause. I'll check the gas heater (it isn't used and doesn't work any more) so maybe I should bypass it. I removed the chorinator because it started leaking and we always had too much CYA from it - maybe this wasn't done properly.

Many thanks for the advice - it's a great help to know where to look now.

[PoolDoc]

Thanks - I just hoped my system didn't follow the laws of physics.....

You, and quite a few others!

Bypassing your heater is a GOOD idea. Heater internals typically include components that, if they failed, could introduce a BIG obstruction.