Clones turning yellow at the top

You should soak cubes at 5.0 before use…then 5.8 ph use plain water and root hormone only till you see roots 5-7days then light nutrients

Its taco tuesday🌮im guessing you baked them under your light

It's completely normal for clones to get yellow leaves and look a bit sickly, as they can only rely on the reserves in the leaves at the beginning. Give them time and keep the humidity high; the cubes should be just slightly moist and not wet. Lightly mist the leaves; that's enough for watering. A few days after the roots have formed, vitality will return. Good luck!

I found that when that happens, the mother or donor plant was likely already in poor health. It might not look it, but I’ve noticed that to be the case. Could be too much light also

How many watts of light are you running on them? I would guess it's too much light power. Clones root great with low temps around 75f and low light power. I use like 20 watt 6500k CFL lights to root clones. Too much light will fry them.

Half of them look dead already, it's some imbalance, I am not a pro , but one thing sure, get ready to strip that/those plants more if you need clones ... Hope somebody will guess your issue. I was putting mine into water, just in glass for a week, sometimes I was adding a bit of BioHeaven and sprinkling them with cinnamon when had no money and mycorrhizae when I had few bucks ;) and straight to soil after. Worked really well. All the Best !!!