couple of questions, as i am going to drill one of my 40 gal breeders.
do i get a return pump first so i have in mind what kind of turnover i should expect before i decide what size pipes to use (and ultimately precisely what size of hole i'll be drilling)?
or
is there some rule of thumb about this where someone can tell me what inner diameter my exit tubing should be?
also, do i only need 1 hole drilled for the exit? cause as long as my return is at or above the overflow line, it won't siphon too much out of my tank during power out, right? not quite sure how i would put 2 holes to work- if i went with 2 holes, would i be putting them far apart?
simple question- what turnover rate should i be aiming for in a 40 gal breeder tank? modest current, something gouramis are comfortable in, but nothing too calm that an algae eater would get bored in.