1st grow... Need advice

My first grow and I have been researching like crazy and know a lot for the short amount of time I have been doing this, but obviously I am no master... yet atleast. Any suggestions and comments are much appreciated.

Grow Room Specs
5W x 6L x 8H Room
2 (400watt) MH bulbs @ 20" above plant tops.
3 (30gal) containers w/ 6plants each
Water in DWC containers @ pH of 6.0 and 1000ppm
Plants are @ 31days


I have a few plants that are growing great and some that just aren't. Some suffer from leaves curling down and some from yellow and browning bottom leaves, and some from leaf edges curling up.

These are the problems i think i am facing.

800 watts of MH at 20" above may be causing heat stress?

1000ppm too high for plants approx 8inch tall?


Please let me know your thoughts! THX

it sounds like you need a fan on them to stop them over heating...it also helps the stems get strong to hold the buds..what medium are you using..?

using hydroton,

I have a fan blowing on them all day while the lights are on... temps are at 80-84 averaged. and a fan at the top blowing air out for ventilation.

30 gallons is a lot you could use a 10 gallon and save water and fert

I wasn't sure because i figured more room for root to grow into to, right?

You think it wouldn't make a difference if it were in a smaller container?

well if i remember correctly a gallon per plant was enough

then i will definitely be switching to smaller containers, changing the water in these i have now has been a crazy pain. any thoughts about my lighting? two 400s @ 18-20".... too low?

optimal height for 400watts is 12"-15" from tops

Sounds like nute burn. U feeding them nutes?

i have two 400watts though... does the height make a difference with two? or regardless its the same because the watts are the same?

and I am using FoxFarm Grow big in my water. 1000ppm, 5.8pH