I'm not certain what these moth flies or sewer flies are but if they are the same thing as fungus gnats, you might be able to use a product containing bacillus thuringiensis israelensis to combat them (same stuff works against mosquitoes but is safe for fish.)
White flies are more problematic, you might have to use yellow sticky traps against them but more control may be needed.
I've used a little dust buster type vac to catch squash bugs and leaf footed bugs since almost no sprays (terribly toxic or not) seem to work against them.
Sewer flies. Blech! get some fish that eat them. lol.
geckos don't even care for moth flies! We've got tons of gold dust day geckos living in our bathroom w our composting toilet - which has an outbreak of moth flies - and they don't touch them. Fungus gnats on the other hand they will eat all day.
if you are getting moth flies from your composting toilet, I would highly recommend switching over to a simple sawdust bucket for a toilet and do the actual composting outside in a compost pile where you can let it heat up to real hot composting temperatures. Most composting toilet systems don't really compost, they just moulder.
Best thing to date for me has been fly tape from Walmart (.98 per 4 pack) and I place them around all 4 sides of each ibc at the edge of the gravel. Vac is very satisfying but endless pursuit.
Jon, the Spinosad A and D product that I bought while at your place is fish safe, safe for organic gardens and works on a whole host of insects. It's similar to TC's Bacillus thuringiensis israelensis, only it works by way of a different mechanism and has a somewhat broader range of insects it'll kill (or so it would seem). It, like Bt, is a naturally occurring bacteria that puts a damper on the insect day. It works both by contact as well as by ingestion.