Close Loop Head loss

[Chad]

I am going to attempt to do my drilling this weekend. What is the safe distance between the bulkhead and the edge of the glass, as well as the distance between bulkheads?

I need to have three going across the top of section of the tank, which is about 18" in length. The bulkhead sizes are 1" .

[mark]

Have read (caution, on forums) with glass that should not drill closer to the edge than the diameter of the hole. (3" hole, edge of hole to edge of glass not less than 3")

btw, my tank was from Bow Valley and seems they followed this rule.