Ideas needed to attach lights on a eurobraced tank

[Aquavaj]

I was using painted mdf strips but we all know what happens when they get wet. Well let's just say my tank almost overflowed one time when my ato created a siphon and got the wood wet. Looking for some ideas on creating a taller ledge that sits on the eurobrace that the mounting arms can attach to. I was thinking of 80/20 extrusion but way too expensive.

 

[lapin]

PVC board maybe