Do not use a sump if the holes are in the bottom, sides, or back of the tank! If a pump fails you WILL flood your house. Holes in the bottom of the tank will drain water into your sump which will them be pumped back into your tank. Without "overflows" the entire volumn of the tank will drain into and out of your sump if a pump fails. $200 for that tank is a great deal if it is un (or minorly) scrachted. Put bulkheads in the holes and run a simple closed-loop with an external pump. This will provide excellent circulation. Then run a canister or something for bio-filtration. If you run a sump with holes in the tank without overflows I garauntee YOU WILL FLOOD YOUR HOUSE!
Think, if you have an open tank, and an open sump and the entire system is gravity based you most certainly do not want a sump without overflows! I have responded to many service calls in the middle of the night due to just such a situation.
At least run p.v.c. pipes up to just below water level to drain the water. this will minimize the damage.