Cracked MLT

I use a ten gallon rubbermaid water cooler with a false bottom as an MLT - It recently developed a bulge in the side that finally cracked. Its getting worse, and although im not worried about the quality of my mash, i seem to lose temperature more quickly than i used to.

Is this inevitable in the future? I was thinking of moving up to a square/rectangular cooler and also moving to ten gallon batches, but i dont want to invest in a large cooler and build a huge manifold if the cooler is just going to crack in a year.

Thoughts? Experiences?

I switched to a keggle with Reflectix insulation and a 2" foam board top. Worked very well with that set up. Now I do a RIMS recirculation which is even better but really could be considered overkill. I really don't like using plastic coolers with hot water & grain although it makes for an easier & cheaper brewing set up. Keggle will hold 35lbs or so in grain!

I have a 10 gallon Rubbermaid that had the same problem. I used some Goop that is made for plumbing repairs (ie potable water) and it seems to be doing the trick just fine.
Tom