What is proper hand feeding technique?

[CJHP]

I have found SS tongs and the reason I plan to use them is when I vitamin dust the crickets most of them end up rinsing off in the water before being eaten. So far the FBT only hide in the corner behind the HOB water filter. Should the water for amphibians be cycled like an aquarium? I used seachem prime to dechlorinate before adding to the terrarium and let it all run 2 days before adding frogs. They still don't seem as active as described. I'm not bugging them and trying to think of what is making them uncomfortable. The temperature is 78 in the water I believe that is more accurately the ambient temp. Its around 75 here in Ohio and I'm not running AC or anything. These guys are huddled up in the corner for 5 hours since introduction. Should I be concerned?

[CJHP]

I am mostly concerned with the fact the crickets that have been dusted spread the vitamin powder all over the terrarium and in the water. I assume that's not a good thing (it certainly doesn't look good). I don't use the feeding tongs in between vitamin feedings.