wbeavers, I have mangroves growing in everything from vases to sumps to buckets. I have no experience or 1st hand knowledge of such a problem, but I have seen the roots of many varieties of trees do incredible damage and apparently exert incredible force in fissures in various buried concrete and plastic structures.
I'm not sure that they would do the same in a glass tank, because most of the force seems to be applied circumferentially (the roots get bigger around after growing into the fissures) rather than laterally (the roots don't actually "push", they "swell").
What I have done with all of my mangroves that are in tanks or sumps is to pre-plant them in plastic mesh pots (I use square pots 8"x8", available at HD, Lowe's, or anywhere that sells ornamental pond stuff). This makes them much easier to move if you need to, though you do need to conceal the black plastic.
p.s. WB, please PM me w/ your address again. I know where the needlewheel is at the moment, and I still need to get it to you.