I am learning as I go and have made a couple of mistakes which has delayed my build. Yesterday I realized I made another mistake by drilling 1" into my tank and then purchasing a overflow (eshopps eclipse L). The holes I drilled are too small and too close together since I didn't have them drilled with that overflow in mind. Now i need to decide what to do, return and exchange the overflow for one that fits, or use pvc pipes w a cap to plug the original holes and re drill new ones which would fit the eshopps overflow. However, I don't know how many holes can be drilled on one side without compromising the integrity of the tank. I have a 75g marineland tank. Thanks for the help!