I have gone both ways with no filtration (air stone) to a sponge filter. I have found a sponge filter that is cycled long enough will give you good results and require less water changes. I use very large tubs (rubbermaid) 36x18x22 and separate them as they grow. I keep objects in there to give them separation and prevent nipping (pvc pipes, rocks, fake plants). I start out with one large container and graduate up to 4-6 containers as they are getting bigger. I reared about 50-80 larva. This method seemed to work well. I keep the lids on them and drilled a couple of holes. This prevented evaporation.
I used the stocky round cylinder sponge filters and added an air stone attachment to the inside to get more pull. The water quality was better. I still did some water changes 1-2 times a week. I would try to remove left over food 3-4 hours after they have eaten (net). I would feed them in the morning and evening.
