Full aquarium setup-please comment and suggest

I don't put the crabs in the 10 gallon because it has fungus gnats. And the heat pad means the water is too cold for the crabs. And the crabs would need an additional food dispenser for vacations. And since they eat varying amounts of food from day to day depending on whether or not they are hungry, either they'd starve or the decaying food would cause anoxic buildup in the sand. Also the water level in the ten gallon drops dramatically and the salinity increases over a vacation, meaning the crabs would die from that.
 
Wow! Talk about dense vegetation! Your auto feeder might be dispensing a bit too much food though, because the snails really are out of hand...Malaysian trumpet snails tend to do that, which is what you have. Do you have the feeder set for two feedings a day? If so, one would probably be better - or even every other day, really.

Your tank is basically a "vegetable filter" as you have it now. I'm sure they are growing so well because of uneaten food and sparse water changes - which may not be the best, but it's far from the worst. The plants are definitely keeping your tank healthy, but removing most of the snails should help a lot. They are generating a huge bioload in and of themselves.

I see what you mean about the one cory. I guess he'll just have to live alone! You probably have a lot of mulm on your substrate, which tends to cause trouble for this species.
 
The mulm is all deep in the substrate, so the cory doesn't care.
And the dense plant growth is how the critters and I like it. It enables me to go on those long 7-week vacations without worrying. The plants can soak up any spikes that would be fatal in a standard community tank ;) Also the plants keep the betta male's field of view small so he only sees fish within a small area he considers his territory. Thus none of my fish are chased around the tank but have to give the male 1/2-1 gallon of the tank for himself.
I don't use the auto-feeder when I'm home. Feeding my fish myself gives me time to observe everything and I discourage people from constantly using their automatic feeder for that reason. And I don't overfeed. I give the fish and frogs their food and sprinkle a few shrimp pellets into the tank for the crabs, cory, plecos and snails.
 
Hmm...mulm deep in the substrate is indeed bad for cories, they root around in the substrate and the high bacteria levels around their barbels tend to degrade them. I'm just saying if you haven't had luck with cories in the past, that's probably the reason.

The assassin snails are probably killing your adults, they don't go after the tiny juvies. You definitely have MTS in there. If you're sure you're not overfeeding then they are probably eating a lot of decaying plant material, although personally I have only ever seen them get out of control like that from overfeeding - there is not a lot of nutritive value in dead plants, but huge "calories" in prepared food.

You're pretty lucky if you can go on vacation for 7 weeks! Family abroad?
 
If you're in the US, it's unlikely. Are you getting plants from the wild? Besides, those snails don't have the white tips which yours have.
 
The picture of the tiny snails is from last year. Just posted it to show u what I mean by "tiny snails".
I haven't found any of those snails getting bigger, even before i got the assassin snails.
 
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