return/drain questions

ok i have a 20 gallon tall that i am trying to finish up this weekend i hope to have it filled sunday night.

my qestions are
i have drilled 2 holes both for 3/4" bulkheads i was going to use 1 for return and one for drain but the more i think about it i dont think one 3/4" bulkhead is gonna keep up with my return pump i dont want to dial back the pump i want all the flow i can get, what do you think?

i built 2 overflow boxes today one for each bulkhead so i could use them both as drains and plumb a over the rim return if i need to which i think i should but i want to know what everybody thinks about this i really dont know if i want to drill another bulkhead but i can if i really need to.

let me know what you think would work better?

 

in that case i would return over rim unless you drill another hole . i air on the side of caution and always run 2 returns at minimum incase a snail finds his way at the most inopertune time and thay will its like thay know your not at home and wont be for hours ... its cool to dial down a pump but i wouldent use that as a failsafe if i cant run a pump at wide open i had more return

 

ok so i got everything setup enough to test run my return and drain and figure out my sump depth today only to find out that my drain is only good enough at full vacume which drains the tank way to fast so i drove 40 mins to the only shop in town to get another 3/4" bulk head im gonna drill it tomarrow and see how it goes.

also what do people do to hush the water in the sump if i submerge the drain pipe i hear load bubbles in the sump if i have it above the water level it makes a load crashing noise how do i deal with this, i know some noise is going to be hand in hand with a salt tank but this is way to much.