Originally Posted by Brookster123
Haha.. this! He could make sense of that picture upside down and backwards..
Ha it showed NO PICTURE on my end ...I am all wrong of course...
One with 'loc line' is return ,one with 2 90s are out to filter.
The other two look like makeshift overflow failures which IMO
are not needed but do have to plumbed to sump as they will both let water out if something goes wrong with outflow in corner box.
So really only two of those holes will/should ever do anything.1 in 1 out the other 2 ??? OVERKILL FROM EXCESS PARANIOA???