HELP! overflow sump questions

[cathyg_99]

okay so i have a 90 gallon which i plumbed and set up(the overflow ect was already drilled) inorder for the pump to stay submerged i have had to add water up to the metal casing 2cm more and it would be on the floor is there usually that much water? or did they just not cut the overflow low enough?? my sump is also really full in the first two baffles so im also concerned that if there is ever a power outage and some water does get sucked back itll be on the floor....


and yes im an idiot for this... i didnt put a tiny little air hole in the outflow so if the pump stops it wont pull all the water in my tank back with it... how should i do this after the fact? and yes i glued it (i know im an idiot!)

any suggestions that dont require pulling my whole sump out??