I just picked up a free 55 gallon acrylic tank. There's this small circle of cracks, maybe a half inch in diameter I noticed on the bottom of the tank. It's smooth to the touch on both sides. I was wondering how to go about fixing it, or if I should worry about it? I was thinking either using weldon to patch over it with a piece of acrylic, or drilling it out and installing a bulkhead. I'm just going to use a sponge filter so I was thinking I'd just use it as a drain for water changes. What would be a better way to go?