Thanks! I'll definitely use those tips!That’s good to hear then considering dart keepers are the bio masters!
For the substrate bin, just 2 things that come to mind(that I didn’t do the first time around). Polyurethane/waterproof the whole thing, even in spots that don’t get wet. I didn’t bother with the bottom of the stand, but the humidity from the drainage tray caused mold to grow underneath. The other thing, I’d do some sort of ventilation between the pond liner and wooden substrate bin. Maybe have a vent in the sides and at the top or something. So any moisture that gets trapped between the liner and the wood won’t cause problems down the road and is able to evaporate.