help needed with cloning

ok i am new to cloning but have been growing for the past few years. I have a few different strains going i got white widow some strawberry kush and some good shit i found a few seeds in and grew. I bought a t5 ho 4 bulb for cloning i got it about 2 feet above with a heat mat with a few pencles on it so the tray is not directly on the mat. I soaked the 2 inch rockwool cubes for 24 hours with one drop of superthrive per gallon. i took four cutting from each plant at the second or third node down and made sure to cut at a 45 with a node buried in the rockwhool. they are fairly small cuttings about 3 to 4 inches above the rockwool. i put them in the dome for two weeks airing them out each day for a few min. The clones look very healthy and stay green but absoultley no sign of roots after waiting the two weeks i pulled them out of the cubes and there was no roots at all NOTHING. It looks like rot but i only watered the cubes on the original soaking and they stayed moist but not soaking. I cant figure out what the hell im doing wrong and im obsessed with trying to perfect this process. Someone please help! I also recently took three of the four bulbs out of the ho t5 unit cause thats the only thing i could think of is too much light

I've never tried rockwool. I hear it's very PH sensitive. I clone with 3oz cups and soil. Same size cutting, or smaller. I have re-cut a few that didn't root, split the bottom of the stem lengthwise, re-hormoned them and had roots in 5 days. I now split the stems on all my cuttings.

Always soak the rockwool in water PH adjusted to 6.5 before using. Try just putting a towel over the mat and your tray on top of the towel, that should give you more heat which I think is the problem (If they are too cold they take forever to root) Rockwool is a very finicky medium to clone with, it is very easy to over/under water your clones .

I use a gel root tone, seems to work better then a powder...not sure which one you are useing, and make my cuts under water so as not to get any air bubbles in the stems. I also use rockwool and seems to take some time to root. my problems have just been keeping temp and humidity consistent