Need confirmation of overwatering/over-nuting/possible phosphorus def?

GDP Indoor grow 400W MH
Watering about every other day/every three days with nutes once a week
In soil
Vegging on week 6 after transplant

Gahhh for the life of me I can't pinpoint the issue. I read all the guides but this doesn't fall into any one category. I am either over-watering, unnecessarily using nuts, or theres a phosphorous deficiency. If you look at the pics you can see the top leaves curling downward, but the lower leaves getting burnt edges.

I make sure to check the top 2 in of soil to make sure its dry before watering. I did start nutes a little early (week 3) and this is only happening to the 2 smaller girls. I give them all the same amount (2 cups) per watering, so that makes me think I should give less water to the smaller ones to fix this.

I never give them enough for it to drain out the bottom. I'm afraid doing this has led the roots to not get dry enough and caused a fungal problem. Do they prefer more water/less frequently or am I good with this rate?

I'd say overwatering. Had this kind of issue during my current grow, I really had to let them dry for a few days before watering again to let the roots breath a little and make sure I didn't get root rot.

Maybe let them dry until they're really thirsty (slight signs of under watering?) Watering every 3 days doesn't seem that bad but I'd also make sure you get some run off and water less frequently.

@geero appreciate the quick response man I'm definitely upping the amount per feeding.

However now I have a friend advising that they aren't getting enough nutrients now They've only recieved nuts once a week and the soil is getting depleted so that makes sense, I think I am going to up the frequency to start fattening them up

nute burn, and you should water till you have 20-30% run off

OMFG After doing more research my problem seems to fit all of the early symptoms of spider mites. I am continuing treatment (Mighty Wash) I thought I had a handle on this a few weeks ago but I guess my clones are cursed for life