Most of the time you just fix your own filters when they break..
The fluvals fetch quite a high price on trademe almost or even more than a brand new aqua one so id just buy one of them but that doesn't help you now. If you google around you should find a parts break down for them and buy the bits you need to fix them, the electrical fault maybe hard because the tops sealed, so unless its the cord (and you would have to get that repaired properly because its close to water). If you need advice on how to fix them maybe post pics on here and people can try and help..
I don't leave my water to stand at all I just use the hose straight into the tank, if I was worried about chlorine I have a bottle of super concentrated dechlorinator thats for ponds it works out really cheap I used to use it but gave up and haven't had any problems..