What size e drains again ?
I started off with the gate closed then gradually opened it until the e drains werent taking on water. Mark the water level in the sump that allows for back flow when you shut the system off. Make two marks - the off level and the running level with masking tape. It will take tinkering for the 1st couple of weeks.
As you lose water to evaporation the level in the sump and over flows will drop (display tanks level will stay the same). The lower the level in the overflows the louder the water will be when falling in from the tank. If you adjust the gat (close it) the level in the overflow will rise and fo back to being totally silent but imo thats just a p.i.t.a to constantly tinker.
Now when you refill during wc or top off because of evap you use the tape marks that way the pressure on the gate will be the same no need to tweak it.
Im happy i went with the 2 inch e drains that way if i refill a little too much and they are taking on some water i dont worry about adjusting the gate valve the system corrects itself over night amd the larger e drains can handle the flow if something gets clogged
I havent touched my gate in months