Metheylene Blue is added once (As according to my knowledge) just to stop fungus from attacking the eggs. Thats its only purpose. You will want 2 sponge filters running on the tank. Add a slow bubbling air stone next to the eggs to aid as an aeration source. When the eggs hatch, and you have wrigglers, remove the air stone. Keep the 2 sponge filters running. When they start to free swim, about 5+ days after they hatch, feed them baby brine shrimp/cyclops/daphina.