New to sump and have some questions

im new to the sump stuff aswell my setup is for a 75 gal and my tank is only 45gal the lfs said that it would work well in there i set it up and it works wounders tis video help it helped me hope it helps you

YouTube - How to - Aquarium overflow / sump / refugium. Some tips

 

If your sump is smaller than you DT your sump will go up by much more than 6 inches if your DT goes down by 6".

I use 1/4" holes. Mine were getting clogged at 1/8". Use more than one hole for the siphon break just in case a snail happens to be sitting on one when the power goes out.

 

I'm just in the process of building my new 65G tank and sump. For added protection, I am doing the siphon break, as well as an inline check valve on the return line. If power shuts off, the check valve should prevent any water flowing back. It's a flapper type, to there is no spring force to overcome.