[Mark7]

I replaced both my grey and black tanks as they were old and pretty cracked up. My black tank was cracked along the top edge where the lid is "welded" on. I was told it likely froze when full at some point... not while I owned it.

Another piece of advice I got was not to travel with full tanks as this puts more stress on that area of the tank.

I did all of the work myself... from the bottom side and it was not a real big deal. I did have to cut one cross brace out with a side grinder and I welded it back in place after replacing the tanks.

I did fix a small leak in the galley tank using the ABS pipe filing and glue method. It worked great!

I also installed Horst Miracle Probes in all 3 tanks while I had them out. That has worked out well.

Good luck!