[untamed]

My tank is just different...Waaaayyy too much misc. life to risk losing with some sort of toxin.

If anyone else wants a non-toxic approach to control (not elimination), I've discovered that these little beasties can be nicely siphoned using small piece of rigid airline tubing connected to flexible airline tubing.

The airline tubing is so small that you can spend some quality time siphoning up the little buggers without removing a ton of water at the same time. The rigid end give you something you can aim with precision and makes it easy to hold (like a pencil).

Once you have a bucket full of water and flatworms, you can just put most all the water back in leaving the worms in the bottom of the bucket.

In only two sessions, I've reduced the population from 'carpet', to 'hard to find'. I know that I'll have to do this periodically for ever....