What I do works for my water parameters, it took several tries quite some time ago to get it right.
I start with 100% fresh dechlorinated tap water, same temp as the parent's tank. I use 4 drops/gal meth blue, 3 drops/gal Maroxy, and a drop or two per gallon Acriflavin. I do use an airstone to diffuse the bubbles, it doesn't seem to matter if they hit the spawn, or are near it, as long as you have a decent flow without knocking them around too much once they are wigglers.
Here's a little hatching chart;
Day 0: Eggs spawned in streaks, are clear or translucent.
Day 1: Some infertile eggs turn white.
Day 2: More eggs turn white, wiggling tails emerge from clear eggs. Some white eggs may get fuzzy.
Day 3: Tadpole shape forms with large yolk sack, fry remain stuck to the slate.
Day 4: Small eyes form.
Day 5: Eyes grow large, yolk sack shrinks. Start brine shrimp hatchery.
Day 6: Some fry are free swimming.
Day 7: All free swimming, time to start feeding.
On day 4 I start doing 50% water changes with dechlorinated tap water the same temp as the tank. Watch how fast it flows in, sudden turbulence can take out a spawn. This is one of the few times I still use a bucket, to get the temp on the money, and pump it in with a small weak powerhead & tubing. I used to have a piece of eggcrate and the bottom half of a gallon jug with a few 1/8" holes poked in it to trickle water in. Just put this over the tank & pour water into the holey jug. The large piece of tubing I use to drain has a piece of sponge over the end to prevent fry from being sucked up.
Once they are swimming I add a clean mature sponge filter in place of the airstone. I also keep a light on them the first couple of weeks, this keeps them off of the bottom, where bacteria seem to settle. I add a small cory, barely past what would be considered fry, to keep the bottom clean, some people use bristlenose plecs, just remember to keep them small. Larger corys will eat the young fry.
The tanks are bare bottom, to clean the bottom I use a potato chip bag clip with a folded up paper towel to wipe the bottom. I also use a piece of air line tubing attached to a wooden dowel to clean the bottom. You can control the suction with your thumb over the end in the bucket, this takes a little practice. Don't worry if you suck out a few fry, just put them back in with a turkey baster. I continue with daily 50% water changes for the first 10 days, then switch to every other day. By about the third week they are getting large enough to go into a 20 or 29.
I started with 10 gallon tanks for hatching, that is what I had available. I got some 2.5 gallon tanks after that, they work, but are pretty small for my big hands. I've pretty much settled on 5 gallon tanks, they fit my hand & my rack well. Many people will hatch in 1 gallon jars, then transfer the swimmers.
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