I found a great thread on rc(notice the little "r" and "c", cuz i like LivingReefs alot better. WE"RE ROCKSTARS!! but anyway) explaining calfo overflows(horizontal overflows) and i like it alot. Its exactly what im looking for. But i have seen people talking about setting one of the drain pipes as the safety one in case something happens or something like that, i dont understand this?? And another thing is, i understand why people use "T"'s and drill a hole in the top this is to let air come into their drain lines but why am i seeing some people with the hole and tubing coming out of it??
Can Someone explain...TIA