Scleromystax barbatus eggs splitting

[Douglas stone]

My scleromystax barbatus have been spawning and although I've hatched and raised some fry from previous spawnings, the last two batches of eggs have been splitting two days after being deposited on the tank.
I remove the eggs and float them in the tank with a 60/40 ro/tank water mix with a almond leaf and air stone then daily water changes. The nitrates are 5-10ppm, ammonia 0ppm nitrites 0ppm, 6-6.5 ph. The first batch that went bad had a red ramshorn snail in with them, so I left it this time but with no joy.
Any idea what could be causing this?

[Bas Pels]

Personally, I would not expose the eggs to any different circumstances. That is - I would use 100 % tank water, of the same temperature

ANY change of circumstances makes it harder for the eggs. So these changes should be avoided.

Later, you may change water (while developing not too much) but why use RO water? S barbatus do not come from the Amazon region, but much farther to the south. Where the water is not extremely soft.

There, I would expect the water to have a conductivity of around 200 microciemens. That is rather close to what I have in my tap (300). Obviously, if your tapwater is harder, you might want to soften it up a bit - but then, the parents did breed in this water, didn't they?

If this does not work, you might want to soften the parents water to this conductivity