100% agree. The more you tinker the more creative you get and learn neat tricks. The reason why I like ball valves on overflows is because you can fine tune your flow to suit your preference. I have a 250g in wall aquarium in my media room which has an overflow box and ball valves on the overflow pipes. I've fined tuned this system so the water level sits mid range between the main drain and emergency drain. The running noise on this system is whisper quiet, in fact the brand new fridge I recently bought is louder than my 250g. I also customised the sump with the overflows draining into stackable containers. Kind of like the tote draw diy sump.
I also use Ts on all my overflow pipes on breeding racks, with a caps drilled with a short piece of airline tube running down into the water level to lower the gurgling noise when draining. My 85g 3 tier rack overflows are all fitted with ball valves and I have fined tuned for a quieter running system. I also use the same sump filtration design as my 250g display tank in the media room.
My quadruple breeder/grow out rack for which I started this post is running nicely, all overflows are fitted with ball valves, however I haven't had to use these yet as I'm happy with the noise level and the amount of flow running in each tank and sump, but the good thing about having ball valves in place is that I can cut shut off particular tanks from the system and run them with a seperate heater and sponge filter to raise fry.
