just buy you a 55 or 75 gallon tank and buld you a new, sweet wet dry 
edit: just found your pics link, sorry. I'm running the same wet dry on my 300 and don't have any issues. make sure there's no back siphon created from the return lines. unless you already mentioned this, then i'm sorry. just breezed through. long day.
edit: just found your pics link, sorry. I'm running the same wet dry on my 300 and don't have any issues. make sure there's no back siphon created from the return lines. unless you already mentioned this, then i'm sorry. just breezed through. long day.