I have often been asked how I store all the water blasters I have accumulated over the years. The answer is: with a lot of effort!
After passing a several hundred item mark a few years ago, I found myself with a definite need for being able to store things decently. That said, while my current system is ok, it is far from optimal and someday, time and more free money permitting, I want to better organize my collection. In the meantime, here is a glimpse of what I consider as "deep storage" for me.
The furniture unit shown is a Pax Wardrobe purchased from Ikea. For those familiar with this particular piece of furniture, it is nice, boxy, and deep. Behind the Super Soaker CPS3200 box are Monster X and Monster XL boxes. On the top is a fairly large Rubbermaid bin that fits happily within the wardrobe unit that holds a number of smaller, non-boxed water blasters. The entire set-up is kept in a temperature controlled space that is low in humidity (but not desiccating) environment.
What I'd like to eventually do is pack the contents of the large Rubbermaid bins into clearer (or at least better labeled) containers and, perhaps, bar code or even QR code everything for sake of properly inventorying things. One day...