I noticed today I made one fault in my design.. if the pump stops, water flows back trough it also and not only the overflow.. So i've got an out take at half of the tank that means that the half of the tank flows back to the sump..
I just know that if u add a long length of hose or to many corners to the out flow of a pump u lose a lot of water pressure l/h.
This is what I've done. Cut a piece of plexi glass in the size of the inside and length of the weir, not longer else you will limit the flow trough the fitting.. Mark the holes for the screws.. Dril a hole of 4mm and use an m5 wiretap.. I had an unused inlet hang on thingy that had the screws that I could salvage..
Maybe I have to round off the sharp corner of the glass if it is to noisy but it is easy removable so I can always change that..