Hi I have a waterbox 15 aio aquarium and it is currently stocked with fish and corals. I was wondering if it would be possible for me to add a sump, and if so, how should I do it? I know I could either drill it, or have a hob overflow box, but I feel like drilling it would be complicated. I also know that hob overflows are unreliable and bulky. Any type of help and input would be greatly appreciated. Thanks