the reason i believe you are losing crickets is because they aren't getting much of a diet by just eating carrots. they need a high protein diet with some variety. sometimes, if they don't get this, they will resort to trying to eat each other... and crickets do mold fast, so i know it's not the carrots
also, if your crickets get a lot of nutrition other than what they receive from carrots, they'll survive faster.
first off, make sure the temperature doesn't get over 85F coz that's when the crickets will start to become blackened, wet, and then die off in large numbers. secondly, your water source is fine... a variety of carrots, oranges, and green leafy veggies are good, but you can always stick to one of those. your food source should consist of either rolled oats, bran, or unmedicated chicken feed. rolled oats can be found pretty cheap at the store and chicken feed is around 15cents a pound at the feed store near my house. You could also try making a mixture of dried dog or cat food or crushed dog or cat dry biscuits - i heard those work pretty well. you can mix and match any of these
so not only are they getting the high nutrition count that they need to survive longer, you are also gutloading them to make your lizards healthier 
make sure cleaning products are kept away from your crickets. When crickets are dead on their backs, they have been poisoned.
hopefully this helped you a little bit... let me know how it goes and i hope u get more help from other folks on this forum 
[aimEe]
PS: i heard that you shouldn't use corn based products that get moist and humid for your crickets. that generates toxic bacteria that can make your leos sick~
take care!
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0.1.0 Albino Leopard Gecko (Marlene)
0.0.2 Fire Bellied Toads (Norman & Forman)
1.0.0 Fighting Fish (Blue Balls)
0.0.1 Hermit Crab (Kerby)
1.0.0 Black Lab / Pit Bull (Mikey)
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