Top leaves curling up

Hey dudes, iv got a plant in my mini grow box (see album) and the top of my plant is curling upwards.

Its not to hot, temp is steady around 24c or 80 degres... ( I read about this subject and lots of poeple seem to think its about heat)...

Im still learning about growing in a box so ill try explain things that might be a problem:

1. I think i did a mistake... im growing the plant in sheep manure compost, lol, no top soil, no sand...nothing ealse exept for sheep compost , is this my problem?, my buddy says it was crusial for me to mix it with top soil.

2. Its growing in a self watering bucket that i created myself. Can they be over-watered? Its perfect because the soil is always moist, I never top fed her yet. I just fill the water reservoir, and the soil siphon's itself...

Thx for all the help, peace

Mine jus did the same thing I switch from a 24/7 led to hps and at first she waz loving it but I jus saw that and it can't take all that power so ima go down to 18/6


But yours might b overwatered cuz mine alwayz like it dry and if they get to much they either sag or point up and try to release sum of the water through their leaves