How frequently should I change the water for the larva?

If I decide to raise my eggs in tupper ware, how frequently should I do water changes for newly hatched larva, and at what age would I be able to place them in a divided 20g long tank cycled with a sponge filter? The water level would be full.

what is the age of your larvae ? i raised my last batch of eggs in a well cycled 10 gallon with two sponge filters and a small air driven waterfall pump from the time they were eggs till about one month and about one inch in size then i moved them to a 30g long tank for more space. shoe boxes/ tupperwares are more for those that dont have aquarium space available and will work in a pinch but imo a small tank with tons of live daphnia does the trick and as for feeding baby brine shrimp (bbs) i only fed mine on bbs for a few days untill i noticed the daphnia in the tank disappering. so if you have the tank space use it, oh and dont leave the light on all the time, it causes unnessary stress and also raises the water temp and to answer your original question if you do decide to still use tupperwares i would change the water out with water of equal quality a few hours after each feeding depending of course of the water volume and size of your containers respectively.