hi Ed,i do understand your concern's with adding supplements and as of reading i think i will stop this as i too would worry about giving my frogs lethal doses of vitamin's,although i never go over board with how much i add..
this is my fruit fly mix as it's been since virtually the time i've kept dartfrog's
4/5 types of fruit i.e bananna,apples blueberrys,raisans, maybe pure non concentraited orange juice,tomatoes carrots in every mix,for water which is osmosis wihich is built up to 6.5 ph with replacement minerals,two cups of readybrek,uk brand plus 1 cup of regular oats ground up coffee grinder then small half uk teaspoon of something called herpetal amphib,thats it then mix all the fruits water and vitamins in blender then add to the oats,and my flies are always swarming..but on reading i will cut out the vitamins.
but i do like the idea of adding wild growing veg like the grass as it is rumoured if someone where to be living in the wilderness they could almost live exscusively off it as there are proteins,fats minerals and the chlorophly is meant to help against types of cancers in humans so hope long term it would only be good for frogs,as also i think nature does it truly the best.