What's poisoning my plants?

[Brain-decorator]

I am a grower for 25 years (showing my age) and for 15 of those indoors in Holland. I consider myself a very good horticulturist and it’s what I do for a living. In all those years I have never had a problem like this so, for the first time ever instead of trying to solve everyone else’s problems I need help to solve one of mine. Please if anyone has any information about what this could be answer this post.

About a year ago I built a new room. It’s on the ground floor of an old (150 years) building in a room build within a room. The room has 8 lamps (+ adjustawings) and ample air coming in direct from the garden, and going out (3500m3 out / 2500m3 in).
I’m growing in soil (allmix) 16 x 6.5lt pots per m3.
I’ve built many rooms just like this and it’s a great system.
Anyway this particular room isn’t, and now after 4 failed crops it’s time to ask for help.
To cut a long story short the young plants when moved into the room look ok for about 3-4 days then no matter what growing medium they’re in (they have all been tried) they start to turn yellow (chloratic). As you will see from the pictures it’s not a nitrogen deficiency yellow, it looks more like a magnesium/iron deficiency. As well as that the new growth, which is very slow to come on, is whispy and soft, so soft when brushed the tops fall over. The plants under the lamps fear the worst, while some of the ones more in the shade seem to be greener and healthier, which tell me the ones under the light can’t handle the light. It’s as if the plant can’t produce chlorophyll and starts to steal it from other parts of the leaf. The yellowing can be blotchy and then interveinal, leaving veins green. It seems to start with middle leaves rather than older leaves or growing tips as with most other problems.
To me it seems like the plants are being poisoned by something in the air. The biggest give-a-way, and the clue that will eventually solve this is that the room has a weird smell! One friend said it smells like a pet shop, another swears it’s the same smell that an ionizer machine makes, a bit like it smells after rain has fallen. Whatever it is it’s killing the plants. We though about the soil, but we’ve tried several different types and it’s the same with all of them. I have removed all plastic floor lining as we thought it could have been that – no change. I have increased the air flow so we have more than enough in and out. This did help a little it seems but still they die. All it is doing is watering down whatever it is that is in the air killing them. It can’t be something simply off-gassing like the case of the Hydohut tents as it would eventually stop. This keeps going and that leads me to think it’s being generated all the time.
Now I’m looking at my ballasts all hanging on the wall with the switchboard and starting to wonder if they could be the problem. Could the 8 ballasts that hum away on the wall be generating some sort of gas/ozone? They are the only other thing left and the smell seems to be stronger closer to them.
Surely someone else out there has had a similar experience and can help me out. It would be a shame to have to give up on an otherwise lovely garden.

[Jonboy]

I'm not an expert in growing, I'm sure other members will have other possible hypotheses regarding nutes and methods, I'm just thinking logically here to try and help.

Have you ever had a successful grow in the building or did you build this new grow room a year ago when you moved in? If you have been growing successfully until the point at which you moved in then a possible cause of your troubles is the building or something peculiar about it.

What are the walls made of? Are they damp or porous? How about the floor, could something be seeping through it?
What are the walls covered in, I'm thinking lead-based paints if the paint is as old as the building.
Could there be a gas leak? I had a tiny leak in my front room for over a year before someone with an acute sense of smell discovered it and I later confirmed it with the gas company.
Could there be a possible contaminant in your local area? Factories, businesses, sewage works, mines which could affect the air quality you blow into your grow room?
Is the mains water quality different than you are used to?

I'll keep thinking.....

[screwdababylon!]

very good questions man
i guess the answer is somwhere nearby

the only thing i can suggest now if u suspect ballast
get some cfls in there and swich off the ballasts for a while
we will try to help u man

thats a nightmare for every grower

may the force be with u

[screwdababylon!]

no replys man?

i remembered about your problem
and was hoping to see some improvement here

i was struck by some mysterious death too few days ago
got no clue as well