no problem! We worked it out to be more expensive to do the panels but we didn't do much research so can't be 100% sure, and can't remember the figures exactly. However, we did work out the tank price on a very basic model, and ended up getting a more swish one that pumps water to both toilets and has a tap on it etc, so that ended up costing $3500 which may be more than the panels, not sure ... but in any case we have a better tank system than what the builder would have provided as standard so it's all good... good luck in your decision.