Resealing holes in the bottom of a tank

[Crystalab9305]

I bought the Hydor Pro 600 for my 200g tank. With this cannister, I don't need the holes. Any ideas on how to plug these holes?
While I'm at it, should I hang the input within the glass box? or in the main tank itself? The top inch of the glass box has on overflow allowing water to get in (thus I need to plug these holes)
Thanks!
Crystal

 

[Fresh2o]

Get an appropriately sized bulkhead fitting with threaded connectors (or slip + threaded as long as the threaded end in on the part that will be outside of the tank). You can get a threaded plug and screw that into to bulkhead fitting.