I have a 47 gal tank and its a challenge for me to keep my mandarin fed, fortunately for me she has no comp for food and my live rock takes up about 3/4 of the tank. Ive had my mandarin for about 3 months and shes actually gotten a little fat so that means shes eating, a lot! she eats small brine and mysis shrimp(hope is spelled it right, y'all know what im talking about lol) when i toss them in every week or so but this is what i did i basically super over loaded the tank with pods i probably started off with close to 35,000 give or take from copepods to tigers and rotifers and ill just randomly buy some every few weeks its cheaper to feed the pods than the fish so far that has worked out great for me but i only have one with my anemones or anything really to compete with her for food (im building a little fuge to just breed them in but its not done yet) but yea like everyone has warned 2 mandarins is a lot of pods so your best bet if you want to keep them, id say would be to just buy a ridiculous amount of pods that way they will breed faster than they are eaten and it would benefit you to just breed them yourself to save on the money and trips to the store
P.S. i usually turn my emperor 400 off for about 5 to 10 minutes and open my pod containers as close to the bottom as possible so they don't get sucked up into my filters