Cleaning question

[Sanimal]

Hello! In my green tree frog terrarium I have a false bottom. There's about an inch of water at the very bottom with a pump down there. I stuck together some pvc pipes to form a square; I put this square in the water at the bottom and lay some mesh on top of it. The pump has a tube sticking out from it that goes through one of the holes in the mesh. The tube comes up through the substrate (eco earth and live moss) and goes through a hole I drilled in a rock. When I turn on the pump, it pumps the water through the tube up the rock to create what looks like a "natural spring". The rock sits on top of the substrate. Once about every three months I change the water at the very bottom, change the substrate and clean the pipes, mesh and tube. Should I clean it more often? Is it safe for my frogs the entire time I leave it in there (some eco earth does fall through)? There's always algae by the time I take everything out and give it a good cleaning. I do clean the cage decorations (plants, vines, water bowl, worm dish) once a week.

Thanks for any advice!
Sanimal