The vivarium construction 101 thread was most helpful. Certainly taken on board a lot of what's said in it.

My current project is basically my *Big One*. I've done extensive research and puzzled over many potential pitfalls for hours on end.

I'm thinking external filtration, pumping etc. Main thing I'm wondering about atm though is heating the paludarium. I know the temperatures the tank and water need to be. The question is, hot to attain them.
Lighting will provide some heat and a strategically placed heat mat will prove beneficial for certain plants and animals. My question is this - How do I go about heating the water portion or would the heat from lighting provide sufficient temp increase?

The obvious answer is with a standard aquarium heater hidden away. With this method though, I worry about accessibility. If I need to replace it I don't want to have to dismantle portions of the tank. Would it be possible to heat the water externally?
If the water reservoir, pump and filter are external, could I plonk it in the reservoir?
I've had trouble with aquarium heaters in the past. I have also had problems having to remove backgrounds etc to access heaters/filters. This is why I ask.

My brain just isn't on form today so I can't seem to think of a solution xD