Originally Posted by EA37TS
I doubt it would be easy to access to move the flush and to also put the hole in the grey tank.
You say it is a new Miramar so if it were me I'd take it back to the dealer and have it repaired under warranty and I'd tell them that if it is easier to leave the current one in place and just install a new one in the black tank.
I Concur.. Nothing wrong (and it may be an advantage) to have a tank flush on both black and the gray tanks...