Where to buy weir boxes

[FishOkay]

Does anyone know where I can buy pre made weir boxes which I can then just silicone to the walls around my drains.
My 2500L pond at the min is on two 50mm drains (bulkhead and then elbow) on a full siphon. It's working for the min but my sump won't take all that water if my pump fails.

 

[56longroof]

I got mine from Melvs.

 

[FishOkay]

I got mine from Melvs.

Where's that. I should have Said I'm in the uk. Although don't mind if they do international shipping.

 

[56longroof]

Where's that. I should have Said I'm in the uk. Although don't mind if they do international shipping.

https://melevsreef.com/