Advice almost outsider crabs?

Okay I have two hermit crabs in a 5 gallon cistern. It has a section of sand and a section of rocks (green and small). Okay I looked surrounded by the tank today to check their water and food and in that were several little flying bugs inside the tank which weren't there yesterday. I open the tank and got rid of the bugs then looked for the wreak. Apparently when the hermies use their water trough & the wading area they splash hose down everywhere. This water coats the sand and the rocks which mix with their food and excrement and attract these little flies. I overturned the rocks and tried to dry everything as much as possible. How do I prevent this and what should I do? I want to take devout care of them but I'm relatively new to owning hermit crabs so I don't know what to do.
What else should I nurture my kid...
Answers:    Check out the following net site
www.hermit-crabs.com
There is a whole section walking you through the cleaning process (or biological warefare if you choose) step by step. Good luck...you've get some work ahead of you.
Why do my guinea pigs feat this...
YES; THEY REALLY SHOULD GET OUT AND MEET NEW PEOPLE.

THANK YOU FOR YOUR TIME.
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