I am going to build the base from brick joined to the side of my house and there will be a big cupboard built underneath for the air pump and filter etc. plus the wiring will come through the wall and straight into the underneath of the base where the cupboard is so it can`t get wet. Don`t want to build a shelter over it, as you say Torrean I think it would ruin the pond/tank hybrid look! although if I have trouble with rain causing it to overflow etc. then a hood or canopy may be the only answer.
Mark.