You can get little hygrometers like this on amazon all day long for pretty cheap. I use a bunch of them installed in cereal boxes for 3d printer filament. Haven't started storing ammo in a humidity controlled box though... Go through it too fast These are the ones I used https://www.amazon.com/Hygrometer-Humidity-Thermometer-Fahrenheit-Thermostat/dp/B0DNKGBW54/ And these are pretty similar to OP's https://www.amazon.com/Hygrometer-Thermometer-Humidity-Temperature-Thermostat/dp/B0DG8ZXZ5D
They need more than just fish flakes, some veggies or fruits (make sure you remove fruits after about 24 hrs so they don't mold) they also need protein sources. Plant or animal protein (I like Repashy grub pie, and freeze dried minnows, freeze dried bloodworms, but freeze dried crickets are good too. Keep them in an airtight container because they last A LONG time. NOT MEAL-WORMS though, they are too high in fat! 'Pods can't digest fat well, so nuts and meal worms are something that should be a RARE treat.) They need moist foods, since this is where they get most of their personal moisture from. I give mine peas (I spoil mine & remove the skins), carrots, broccoli, bell peppers and other stuff. If you've got a bag of mixed veggies in the freezer that's perfect! Pull out 1 or 2 pieces of just about anything, let them thaw and put them in their enclosure.) I have mine on a feeding schedule that works for me:Monday: Meat. freeze dried ______Wed: "Wet" food, veggies and fruits (mine love peas), mushrooms, spinach leaves (I give mine fresh leaves)Fri: Flake / powder like Repashy grub pie, or Repashy morning wood (I usually add a small veggie in there too just to make sure they have enough water in their food) Maybe a bit silly, but it's easy to remember, and it gives them a good rotation of foods for a good rounded diet. Leaf litter, humidity (preferably a gradient from damp to dry, so they can pick where they want to be) calcium. Egg shells, cuttlefish bone, crushed oyster shells are all good options. They need privacy. They need to be left alone for the first couple weeks / month for them to settle into their new environment. Poking around, lifting lids, lifting things and disturbing them too often can stress them out and cause them to die... Other people here also have great input as well.... But a few dying is normal. PS: I just got these (link below) and I love them. I hold them in place with a strong neodymium magnet (on the outside of the enclosure). This lets me keep an eye on the temperature (in F) and humidity levels so I don't let them dry out. I hope this helps https://www.amazon.com/dp/B0DNKGBW54?ref=ppx_yo2ov_dt_b_fed_asin_title
I had a similar problem, I wasn't keeping my enclosures damp enough. A lot of my pods dyed off. I started adding about 1.5 oz water each day on one side each day for about 3 or 4 days (maybe more) I watched my pods each day after that. Eventually they started moving around more and doing better. I added the water slowly so it wouldn't swamp 1 side of the enclosure. I also bought these 6-pack of humidity meters (link below). I use a strong neodymium magnet to hold them in place (I got my magnets from broken hard drive magnets, but these magnets are everywhere and cheap too). I love these things already, and the price is dirt cheap! Now I can monitor their temperature and humidity levels. PS: I put a tiny water bottle cap in there with a couple of pebbles so the pods wouldn't drown in it for a cricket... But I am finding my pods drinking from it often! I take it out every 2 days, rince it well, and refill it (literally like about half an eye dropper of water). I hope this helps! https://www.amazon.com/dp/B0DNKGBW54?ref=ppx_yo2ov_dt_b_fed_asin_title

