Reddit reviews IRIS USA Airtight Food Storage Container MP-12, Navy, 69 QT

Dog food storage bins get pretty large. I actually have one of these in storage from a dog that passed last year now that I think about it. Would be a PITA to get the box at the bottom though!

I buy food in big bags, and I use this container. The food I buy is a very small kibble (each piece is like 3/8" circumfrence) and I can fit 2 30-lb bags in the 60-69 qt. You could probably fit one 40 lb bag of a larger kibble with no trouble.

How airtight is that tin can, and how long is the food normally stored? Since you're washing it regularly, I'm less worried about contamination and fatty deposits and more worried about air seeping in.

If it's <4 weeks, I think you're good. More than that and I'd look for something with a tight seal. My dog takes ~8 weeks to finish her bag of food, so I keep it in the original bag in an airtight container to keep it fresh.

Pet food containers for bulk. I got the large one for $25, though.

And these for DME/specialty grains.

Yes, they have a foam seal under the lid that does a great job. I've had no issues in the past several years with grain storage at all. They're the IRIS 45-47qt ones like these, which hold 50-55# sacks just fine (very full to the top with 55#), and they're on sale for around $20 for a three piece set from various places. I got some on Amazon and some from Woot when they were on sale... here's a link to them on woot right now for $23.

A container like this should do the trick. Most of those types of containers are, like, $35 max.