Pure RO water?

[murphinvert]

I was wondering when I do water changes I take out about 10% water and add 10% pure RO water. I acclimate the water slowly into the water. Some of my crs die after doing this. Whats wrong with this picture?

[GeToChKn]

You need to remineralize your RO water when doing water changes. Only use pure RO for evaporated top offs.

Look at it like this (These numbers are just to show, no exact math).

Say your water is 150TDS, 5gH. It evaporates 10, so it goes up to 165TDS, 6.5gH. You top pure RO, it goes back down to 150TDS, 5gH.

Say your water is 150TDS, 5gH. You change 10% with pure RO water. it goes down to 135TDS and 3.5gH. Now the gH is too low for them to molt and they die, they suffer TDS shock and die, etc.

If your water is 150TDS, 5gH and you change 10% of the water with remineralized RO water to 150TDS, 5gH, then nothing changes, the shrimp are not shocked, as to them, the water has stayed the same.

That's the most important part, especially with crystals. Stable water.