If you haven’t sorted the pump yet, the principal is exactly the same as what I did with the Abyzz a200. My output was 40mm so there is an additional piece from 40-32 reduced which you won’t need.
Also you will see the pipe on the input of the Abyzz. This is a 50mm socket coupler (the input is 50mm) and this causes a straight flow of water and helps make the pump silent. So it may be worth getting a 40mm socket coupler for the L2 for the same reason. The L2 is 38mm input
If you look at the picture below, the union connector is there so the pump can easily be removed/replaced. It just screws off.
So with your L2 the output is 31.75mm so the first connector would be a 32mm socket coupler. This needs to be solvent welded onto the pump.
https://charterhouse-aquatics.com/shop/aquatics/fittings/sockets/32mm-socket-coupler
Then you insert a small length of 32mm pvc pipe into the socket coupler and then into a 32mm union connector
https://charterhouse-aquatics.com/shop/aquatics/fittings/adaptor-unions/adaptor-union-32mm
I haven’t measured the internal diameter of the manifold pipe your connecting to, but if 32mm pvc pipe will fit straight in, reasonably tightly, then you just get another piece of pipe from the top of the union connector into the manifold pipe. If not just confirm the internal measurement.
I used Marine grade S316 steel hose clips rather than plastic and they shouldn’t rust. There also not below the surface here, but on the S650 you might be best with plastic as it’s submerged. You can buy plastic worm drives as well.
And if you have never used solvent weld before, ask me BEFORE you get the glue out how to do it, because you get one shot. It’s called ‘weld’ for a reason. I was particularly nervous my first time solvent welding a piece of 45p pipe to a £1600 pump! Lol
This is what I used but they do smaller tubs. You will also need a good pvc pipe cutter
https://charterhouse-aquatics.com/s...glues-and-cleaners/tangit-adhesive-1000ml-can