Ok I am a bit new to oxygen absorbers so let me ask this. Last week I started with my long term food storage preps. I vacuum sealed rice after freezing it for a few days then I put the sealed packages inside 5 gal buckets. I put 1 2000 cc oxygen absorber per bucket, 3 days later the sides of the 5 gal buckets were sucked in. I also used white silicone caulking around the rim of the buckets, the buckets were from Lowes. Is it normal for the buckets to suck in like that?