First grow :) Have a look...

Hello everyone, this is my first grow ever and I just wanted to post it to try to get a couple of answers.
First off I'm not quite sure what kind of system it is, I think it is NFT hybrid or something and I have a 400w MH light on them right now. They are approximately 25 days old from the time the sprouts came up and I'm not sure the type of plant (my friend just gave me a bag of seeds). Right now the average room temp is 77 and reservoir temp is from 68-74 with 45% humidity. The pH right now is 5.5 and the ppm is 375 but a few days ago it was 415(to mention later) and I'm using R/O water too. Right now I have the lights on 18/6 and have a timer running the pump 15 minutes every 3 hours. I'm currently using firefox three part nutes and thinking about get some calmag plus. Now to the problem... some of the plants seem to be a little bit light green and one has a leave curling down and turning yellow with brown spots... then probably half of them have these brown spots here and there on the fan leaves and these are the best pics I could get. O and one more thing some of the new leaves that are developing are missing part of the leaf.
Thank you all for your time:)

Some more pics...

Hey, so I'm guessing I have a magnesium deficiency :( so I just bought some calmag plus and whipped up a new batch of nutrients at 500 ppm because half of the plant look fine. The pH is still at 5.5 and I recalibrated my pH tester today and it was .8 pH off so that might have been my problem too... I took some more pics :cool:

ppms a little high for that age. 225 sounds abouyt right . 225 at time of mix . top off with phed water . monitor ppms .

OK will do, ill add some more pH water to bring it down. I was also wondering at what height i should set it to 12/12 because i only have 3" pots and i dont want them to outgrow them. I've heard around 12" high and they are about 4" right now... that MH really makes them compact. Thank You for your post :)

375 PPM is to much at 21 days old? Why is this? because of his system? I thought he was starving his plants. My plants just hit day 14 and I put them at PPM of 600+ the calmag and other items on top. I think they are growing well. But maybe it is just the system I have, to why I can get my PPMs this high.

Res Change is tomorrow and I am sending them up to about 900 PPM.

These pictures are about 4 days old. Since then they grw so much I had to raise my lights.

just 1 q , why is it so green ? the light that is ?:)

Hey everyone :)
Plants are looking better...except the parts that have been affected, but the new growth looks just fine... I think it was a combination of problems but I think it was a salt buildup on the rockwool so I just flushed really well with clearex. I was wondering what I should do with the damaged leaves? Just leave em or chop em? Hey ...gas... I think the green light has to do with my camera or something when I take pics under the MH light, they look better when the light is off :)

Update... Plants new growth still looking good. Some of the roots are turning a little brown so I decided to add some h2o2 to the reservoir and I have a question regarding h2o2. When should I add more to the res, everyday, every other day or only when I change the res. I also saw a small black/brown fly in my grow area and I'm a little concerned about that so I sprayed some organic incest/fungicide just to be safe. That's about all for today... ill try to post some more pics tomorrow :) Later

sweet as m8 ,:thumbsup: