Some tips for Magic Potions population please.

So I've had my culture for about a year, but I'd like some tips on breeding. Started with 12 and I now have 35, mostly juveniles but I do have some adults, so they have been breeding somewhat, but they don't seem to breed very much? Or at least don't seem to produce many offspring?

I'd really like some tips to get them producing more.

They're in a medium sized tub, home composted leaf litter with bark, dried leaves, 1/3 moist spag moss, springtails, cuttlefish and the occasional fish food treat, but haven't bumped much in numbers since getting them.

Am I missing something?