Sounds like grain mites too me. This happens if there is any type of grain (mealworm grain) mixed with even the smallest ammount of humidity. They usually appear to be white, Or clear and just crawl around and most people notice them on there shelves. Usually you would clean it down with a strong disinfectant, But since this is your leo cage I would just be sure to clean It very good with a mild soap and If by any chance you have a health food store any where around where you live (wild oats, Ect) There is a cleaning product called GSE (grapefruit seed extract) And it usually runs at about $7 a bottle. It works great, And you can really use it for just about anything as a disinfectant, It is all natural, All organic.
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I have a new leo named Mr.Crowley. He lives in a 20 gallon long tank all by himself. Here are a couple pictures of him