I would have to see. Im assuming 2 outlets means 2 drains? Usually all towers will drain to a sump and ultimately can handle more flow and 2 drains is more redundant than one but usually not necessary. More than likely its for flow and 2 pumps is the same idea. If one fails you still have flow while repairing or replacing

@@fishguyruss4349 so how many towers do you have on your tank

We service over 100 aquariums its a mix most have 1 some have 2.

Thank you! I purchased my first tank with a overflow tower and sump from marketplace and the seller was nice enough to set it up and give me a crash course, buuuut I learned that he did some sus Wild West setup in the overflow. My LFS guy is super skeptical and encouraged me to check all of the connections, replace the drain with a set up like you have in yours, uncap the third bulkhead and add the intended emergency drain tube that the seller never utilized, and install a check valve 😫 So thanks for walking me through the bullhead removal and replacement - might as well get it all done at the early stage!