[Fredfish]

My goodness you are thorough. I'm not entirely sure your foam tests are entirely valid though. The 120 I will be taking possession of shortly has a footprint of 30x48", so that's 1440 sq. in. The tank will weigh around 1400lb full, so that's 1lb per sq. in. of pressure distributed over the foam.

A person walking is putting their weight over a much smaller area. if you figure a persons foot covers ~ a 3x12" area both feet would be around 72 sq. in. that's 2.8 lb per sq. in., almost three times as much pressure as my tank exerts on a foam layer. We walk heel to toe, so that weight will be distributed over a much smaller area as we walk.

I did a search and ca1ore here on RC has used pink foam under hist 250/280 gallon tank and over 10 years got 1/8" compression.

I'm sure that mat you got will work just fine as well though.

There does not seem to be equal agreement among manufacturers over whether foam should be used or not. I plan to use it under my used rimless tank for insurance.