Hi :wave:
Indeed, overcrowding can be a big factor in die off. You may want to up the size of your enclosure yes, a 10 gallon is pretty small. Also, if you're not already doing it, give them plenty of places to hide (egg cartons, empty paper towel rolls, etc). Make sure to clean out dead crickets as soon as you see them, as dead ones release toxic gases that can kill the rest of the lot in short order. Are getting small crickets (1/4 to 3/8 inch)? Sometimes the smaller ones are a trickier for some reason, just not as robust I guess. You might find once you move up, things change a bit.
I read some great advice on the forum just a few days ago also: place masking tape around the inside of the container, from bottom to about half way up. Crickets can climb above but can't get above the tape... give them a bit of extra room. I haven't tried it yet myself, but I plan to!
Beyond that, instead of the pre-made cricket food and gel, you might try something a bit different: some moistened beardie pellets for protein, and then fresh fruits and veggies for water and vites. I found that the crickets barely touched the gels and they quickly became rather dried out and nasty. Also, they made more of a mess of the dry food rather than actually eating it. :roll: They gobble the moistened pellets and veggies however. I have very little die off (however lots of exoskeletons to clean up as they grow, especially on the larger orders as they tend to stay around longer).
We use a 20-25 gallon rubbermaid and I order either 250 or 500 (Flukers tends to send more like 400 to 700, respectively for die off purposes I assume). I started with 3/8 inch, and have little issue with die off beyond the usual few a day. I place the food on the floor of the container and use the empty egg cartons for hides. I also use a couple of tubes from my large cricket keeper in there so I can just grab the tubes, plop them in the keeper, and bring upstairs to beardie.
Hope there is something in there that helps!
Best of luck,
Em