That gut load gel you buy does NOT actually gut load the crickets. They need to be eating whatever is good for your herp. If you want to use a pre-made gut load, the fluckers powdered one is ok, but you can make your own for cheaper.
Here's what I use (I generally keep nearly all the crickets alive until they get eaten, though the ones from my local petsmart don't do as well for some reason), everything goes into a blender, food processor, or magic bullet:
I have to feed my dog a very good (and expensive) dog food because she can't have corn (NO dog should be eating corn, it is very very bad for them and they cannot digest it, but most dog food is full of it, it is a cheap source of protein), so I put one scoop of her dog food into the mix (probably a cup, cup and a half you could use as much as you think is good), I wouldn't go with one full of corn though, I don't know if it is ok for herps (most animals cannot digest corn very well). Also, make sure it is dry dog food.
I pre-ground some noodles and added that (I used the veggie noodles, the ones that are different colors).
I had some potato flakes (instant mashed potatoes) and I added those (don't put in too much of those).
Fish food went into the mix.
Rice Crispies too, I think I pre-ground them as well...
I'm pretty sure I put some dried parsley in there (parsley is really good for you, I assume it would be good for them too, hope I'm not wrong!).
I put some calcium powder in there that I have to dust the crickets with, I figure feeding them some is good too.
I also ground up a bottle of one-a-day vitamins (They recommend Centrum, but I didn't have any at the time) and put some of that in there.
I also used the rest of the jar of flukers cricket feed that I had left.
I may have put some other stuff in there, but that's all I can remember. I used a magic bullet, so I had to ground it all up in small portions and then mix it together, then I put it in a jar and put it in the fridge (you need to do that if you use dog food).
What you end up with is PLENTY of cricket feed that is going to last you, and be really good for your herp.
I put fruit in the cricket cage for them to drink, that way no drowning, and I don't have to spend so much for the cricket water (if you get it, try to get the orange one that flukers makes, but the blue on is fine too.). That cricket water (as far as I can tell) is the wame stuff they use in diapers, did you know that? if it isn't, then it is very very similar. It is a gel that comes in crystal form and you add water and it expands. They use it in gardening, diapers and sanitary napkins, home decor, and novelty items (a very fine version that looks like snow, it is very very neat, looks just like the real thing). I was looking to purchase some online for a long time, but I never actually bought any, I think because I got a huge bag of grapefruit that I knew would last me the summer (grapefruit stays good longer than oranges). I also feed them pieces of potato (also for moisture, it has little nutritional value), carrot, lettuce (water again), different fruits, dried apricots (the crickets LOVE them), raisins. Anything your dragon can eat, you should feed to the crickets. You can make up some of the "iguana salad" to feed to them too (it goes bad fast though, that's why I make a powdered feed and supplement with other things). Anything you can get that is good for the dragon that is dried, you can ground up and add to the dry feed. Cranberries would probably be a good addition, I'll have to look into it, they are very good for the urinary tract (and general health) of most mammals, I wonder if that applies to herps as well? The more nutritious the feed for the crickets, the longer they will live (and the better they will be for your herp). Crickets by themselves are basically an empty shell nutrition wise, that's why we stuff them full of stuff that our pets need.
Another thing for crickets is they need LOTS of room to crawl around without walking all over each other. I have read that they have acid on their feet, so walking over one another is actually harmful to them. They will also et one another if they are piled on top of each other. I see people buying crickets at my LPS without getting egg crate in the bag. In fact, you have to tell them to put it in there. They should be doing it no matter what though, because half of the crickets in a bag with no egg crate are going to die, maybe not before you get them home, but in the next few days. Older crickets are also more hardy than smaller crickets, the only thing is, if the herp is not big enough to eat such a large cricket it can lead to impaction, and of course less big bugs is not as nutritious as more small bugs. However, if you decide to buy breeding stock, go with the larger ones, they will lay eggs sooner and live longer.
Hope that helps!
One more thing, where did you get black crickets? I thought house crickets were house crickets? Be aware that generally the darker ones are more chitinous. (I'm assuming the black ones would be more like the ones you find outside).
Ok, I guess that wasn't "one more thing", lol, I think I have more to say.
Herps cannot digest the entire cricket, and if you happen to be lucky enough to have one that will hand feed, it would be a good idea to remove the heads of the crickets (if it doesn't gross you out...) If you ever look at the feces from your dragon, it will have cricket heads in it. It will usually also have the wings in it, if you fed crickets that were mature enough to have them. You should be able to remove the wings on a cricket even for a herp that will not hand feed.
Oh yeah, you can also feed the crickets wet dog food, but again, I would make sure that it is quality dog food. Many dog food companies include rendered, euthanized companion animals (read processed cats and dogs, you might check the wiki on
cPanel®). If you do feed wet dog food, I would do it in addition to the dry feed.
I think I'm done now! Hope that helps!
Also, I don't have any idea what you paid for your crickets, but the cheapest I have found online is from:
Crix-n-Wiggles Feeders