Ok here goes the 5ft X 2.5ft tank dimension first .
MAKE SURE U COMFIRM YOUR BOTTOM BRACING IS 4 SIDE 3"
AND THE EOS SIDE DIMENSION IS SAME AS MINE THEN U CUT .
I hold no responsibility if u cut wrong size !!!
( To play safe u just go popular or big stationery shop to buy those thick corrugated sheet to cut with penknife and try out first . )
Buy 1 big pc and cut the EOS side to try . ( u will see if the slanted part and width will sit in nicely below ur tank )