i am in the same boat. Last night , it was 2nd batch that i m using ro water (they lay eggs so many times before, but i tried tap water, turn out no good) . it's about 50ppm hopefully i'll get some wiggles. From my opinion, wipe down you tank, big WC before they lay eggs and try not feed too much during lay eggs and hatch. My last batch last close to 2 days, i did WC on the 1st day and income water went right into the sponge filter and that created more nasty stuffs in the water, the next day all eggs turned white. This time, i won't do that again.