By keeping them moist 24/7 you are preventing root growth.
You should have the oasis cubes (which I prefer to rockwool btw) in a tray that prevents them from sitting in water, like a tray that's 'ribbed' on the bottom.
The best way to water clones is by misting the plant above the soil. Water in the cubes also tend to rot the stem since it doesn't have an established root system yet.I would remove the humidity dome 2x/day for a few minutes.
I would mist the clones with sparkling water ("soda" or "seltzer" water, just H2O and O2 (carbonated water)) when I had the dome off and maybe a spoonful of water on the cubes every few days; any excess would drip out.
After the 1st week, use something to prop the humidity dome up a little bit more every day, so that when it's removed completely it doesn't shock the clones.
Also after the first week use a very weak solution of nutrients (like 10% strength the first time) added to the misting water; increase this by 5% or 10% every day or 2.