I'm cheap, I use a 2 liter bottle for hatching in, and built a box with a dimmer to contain the light, and heat. The dimmer adjusts the temperature, you can see the setup here;
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You can just as easily use a desk lamp, or other lamp in an enclosed area to keep the temperature at 80F. I imagine a deep drawer from a discarded dressed would work good, a cardboard box would probably be a bad idea due to being more flammable. I've seen people run hatcheries with a 2-liter bottle, and a gooseneck desk lamp on the corner of a table. Anything that provides light 24/7, and a constant temperature of 80F will do.
I used to run my hatchery off of a small air pump; it's hooked into my centralized system now. You do want plenty of aeration; this keeps the artemia cysts suspended in the brine solution.
You can see from the pics in the link how much water I fill with, about 1 1/2 liters. I don't add any dechlorinator, just cold tap water. I add 2 tablespoons of non-iodized salt; I've been using livestock salt, $3 for a 50-pound bag. I told you I was cheap. I also add about 3/4 teaspoon of baking soda, and since doing a little experimenting, 3 drops of chlorine bleach. I've seen breeders add a drop or two of acriflavin instead of bleach; the idea behind either of these is to keep bacteria levels down. The baking soda increases hardness; some folks will use Epsom salt instead.
So, after adding salt, baking soda, bleach and eggs I give the hatchery a good stir, and ignore it until the next night. The next night I pull the hose out of the hatchery, put the hatchery on the table, and shine a bright light on the bottom, this makes the bbs settle to the bottom. I then get what is left from the previous evening hatch out of the fridge, and get my bbs cup, which is nothing more than a large deep plastic cup with a paper coffee filter rubber banded to the top. I take my turkey baster (every aquarist should have a turkey baster) and take the previous hatch out of the old sour cream container I use to store bbs. I have a 1" square hole cut in the top; this lets a little fresh air in during storage. The stored bbs goes into the filter/cup gizmo, and drains while the hatchery is settling. After about 3 minutes I pour a little fresh water into the filter to rinse. A few minutes later I take the baster, and add some of the fresh bbs from the hatchery to the now empty & rinsed out sour cream container. To get past the shells floating at the top, without mixing them in, rub your nose a couple of times with you finger. Touch the surface of the bbs hatchery. Oil from your skin reduces surface tension, and the shells all go to the edge.
Now I add a little more water to the filter, and walk around feeding the older bbs to older fry. Once this is done, I take some of the freshly hatched bbs, and add them to the filter. I go through the same rinsing procedure before feeding these to younger fry. The sour cream container goes in the fridge, the hatchery, hose, and top go to the utility sink for a good rinse and refill, and it starts over again.
This procedure takes about 10 minutes; I try to multitask through it. Many people will get two batches going, one in the morning, and one in the evening. I hate mornings, and don't need this extra 10 minutes of work when I could be sucking down coffee; one batch daily being refrigerated has worked fine for years.
