ok.....considering the fact that you are a newbbie i would suggest you to try and grow into soil since it's going to be your first time......also do not expect to get a kilo (1000grams) out of any cannabis plant using a 400watt HPS light......i was kinda interested on koala seeds myself when i was planning my second grow.....you see i got very ''hungry'' to know how come a plant can give out a kilo (2pounds+) grown indoors......the answer is simple.....you need a very long long long vegetative period....3 months.....also you will need lots of room.....both in headspace and width....so....in order to get that amount of bud you need a BIGGER light.....in my first grow i grew successfully 7 plants despite of my fatal mistakes and managed to have a total yield of 600 grams using soil and 2x400watts of HPS....vegetation lasted 4weeks.....you're on a good track i guess, only think things a bit deeper......try to pick another strain to grow.....take a look on www.overgrow.com and you'll find many other strains with grow reports for them....since it's your first time try to grow a strain that others have grown as well....koala seeds sound very promising but other than their promises i haven't read any grow reports on their strains at overgrow.....i am not implying anything against koala seeds ok? other than that i think that with the lights you've chosen (400 watt HPS), that you'll be able to have up to 0.5-0.75 grams/watt used....and trust me 200 grams of bud is a lot of bud.....actually it might be the right amount for you....just a thought.....as i promised i responded to you my friend...now i am going to light my joint up.....if you have any questions feel free to ask....

take care



NGOS