You haven't said what you're doing when you take clones. Just that you're using rockwool. How big are they when you take them? Are you using a rooting compound? How are you preparing the rockwool? Do the leaves just slowly die and shrivel away or does the stem start to rot? Somewhere something is going wrong and switching methods may or may not fix the issue. I'd look for the root cause of the problem. If you provided a quick step by step of the process you're following someone might be able to tell you why you're not successful cloning in rockwool.
Oh, and if you make a DIY cloner I would use plastic tubing like they do here. When I made mine I screwed around with PVC but if I had to do it again I'd just make a loop with plastic tubing.
For example using rubber tubing instead of PVC.
https://www.instructables.com/id/EZ-Cloner/
I will have a cup of water to put my cuttings into.
I find a clone that has at least 4 nodes and about 6 inches? Give or take.
I’ll cut it at a 45 deg angle and gently scrape the button 1/2-1inch (read it helps promote rooting).
I’ll dip it in clonex and make sure it’s on there. I’ll insert it into the starter rockwool cube.
The rockwool cubes have been rinsed with tap water and then sat in tap water with a ph of 5.5-5.8.
SOMETIMES I’ll add about 5ml of clonex solution (liquid stuff in the water and let it sit in there and presoak. Been trying different stuff because I can’t figure out what’s wrong).
I put the clones in the tray and close the holes in the dome lid for the first 4ish days. After that I’ll open the top openings slightly when I see roots.
I currently have about half my clones rooted and half that are barely starting.
When I put them in the starter cube, I shake the excess water out and try not to squeeze it because I heard it can close some paths for roots. Umm.... shit I think that’s all? I wait about 4 days or something and then will dip the tray inside some clonex solution water at 5-10ml per gal. I’ll let them soak in that for a few minutes. After that I’ll shake the tray to get rid of the excess water then I’ll put them back under the dome lid and light