Coco not draining leading to nute burn?

Hey all, this is my first grow, just wanted to say thanks for all the work you guys do helping new growers out. I'm growing two clones (originally seeded in little rock wool cubes it looks like) in coco coir, specifically the pre-hydrated canna coco solution, in 5 gallon equiv air pots. I'm doing about a 60/40 coco/perlite ratio, but I noticed that my coco isn't draining at all - roughly 40 hours after the first watering with half-strength nutes there hadn't really been much drainage, I'd say the coco was wet up to my first knuckle. The plants were droopy and dark when I got them but otherwise seemed all right, but today I noticed yellowing on the tips of the leaves, and I didn't want to overwater them but I also didn't want them sitting in the nutes and burning so I just gave them some 5.9 ph'd water. Growing under an advanced led 100w that I raised up a bit after I noticed them burning. I haven't been able to check the ec of the runoff since there hasn't been any - I would really appreciate any advice on what to do to get the coco to drain, this doesn't seem normal from the vids I've seen, looks almost more like soil. Thanks!

Make more holes in the pot, and water more. you want at least 10 to 15% of the water coming out the bottom.
Then allow it to dry until the pot is light again....but not dry. Don't let it go dry

I'm not really sure I can add more holes to the airpot considering how they're designed, but I'll drench one of them and see what happens

If anything underwatering would cause salt buildup, if you are heavily watering then you should be flushing out the old stuff. Overwatering can cause symptoms of deficiencies. I would add like 30-40% perlite next time to keep things nice and aerated it never hurts, just will have to water more often. Good luck to you