Working on the plumbing on my growout system. It had a corner overflow which I could not use due to the stand it is on. So I capped it with 1/2" acrylic. Installed a overflow in the middle of the tank to handle the water to the sump. Question is - now that the corner overlow won't be used, I don't want it to get stagnant water, so should I drill some holes to let water flow through or something else?