Quetsion about changing weather and it's affect on tank seams

[earhtmother]

Have had a 55g & 2x90g stored outside in **weatherproof** tarp style shed for a year. Winter temps were -21C/-4F on a regular basis. How worried do I have to be about seal damage from temperature changes? Since our weather here is now staying around 10C/40-50F filling outside to check the seals is pretty much a no go esp the 2x90g and if there is a high chance of the seams giving out I really don't want 90g of water all over my floors. Any opinions from those more knowledgeable than me (which is anyone [emoji57]) I should alao mention 1 of the 90s waa a aump and so has a bulkhead(?) in the side at the bottom

 

[melosu58]

My guess is that the temp. changes could be detrimental to the seams. The expanding and contracting wont help. About the only way you will notice is to fill it up outside and leave it for awhile and see.