Thanks emc7, I'll look into getting one of those.
Right, I've done some more research and realise that the HOB filters go outside of the aquarium on the top? The problem I have is that I like to be able to completely close the lid on my aquarium because the lights are built into the lid and when it's open they shine everywhere! I also have 2 cats in my house, and I like to always make sure that they cannot get into my tank... (as I had a bad experience in the past when my older tank had no lid!!)
Sorry to be such a pain
