View Full Version : Euro System Twin 600w's

02-01-2007, 12:52 PM
I have the Euro System twin HPS 600 watt light set up (single ballast, two lights).

My grow area in approximately 5Wx9Lx9H.

I have two questions ...

Is it okay to run the ballast using only one of the lights (600w vs 1200w)?

Is this amount of light intensity (1200 w) too much for my grow space?

A little background ...

I am in week 3-4 of veg growth.
Plants were under a 400w MH were looking great (10-14" tall, good branching and foliage).
I'm using tap water at 150 ppm, pH 9.0 corrected to below noted range.
Reservoir PPM from 400-600, pH 5.5-6.3, good temp (17C to 25C) and humidity range(30-50% RH).

Last week I switched my lighting system (400 MH to 1200 HPS) to boost veg. and acclimate plants to more light prior to the fruiting stage. The plants looked great for a few days and now I'm showing major stem and petiole purpling. I flushed and switched the res. mix immediately and am hoping for a rapid bounce back. I've also gone back to the 400 MH to allow the plants to recover.

What I'm seeing in my res on a routine basis is increasing pH and increasing ppm -daily! ppm increase of 20-40 ppm/day; pH increase from 5.6-6.3/day. I change my res. at least every 7 days.

Based on ALL of this info (sorry for the lengthy post) ... my diagnostic is this:

1) he light intensity increase causes increased plant transpiration (and a slight increase in room temperature (max temp 26C).
2) this resulted in increased water uptake by the plants, hence turning my nutrient mix into a salt brine! -well, not quite I guess, but close
3) now I'm dealing with nutrient lock-out, or, possible a deficiency, which I have/am working on correcting at this point.

I have a feeling that increasing pH and increasing ppm is not a good thing in your hydro garden.

What the heck is going on in my garden and how can I control/correct this from happening again!?

02-05-2007, 10:53 AM
Well, in case you were/are interested ...

The fix to my problem described above was simple = increase air intake!

I guess my ppm of atmospheric carbon dioxide (~300ppm) was being depleted by the plants faster than it was coming into the room. Instead of supplementing with C02, I decided to draw more fresh air into the room.

Now, everything is happy :D

02-06-2007, 12:47 PM
Fishhead, nice thread. I have found that in Veg the ph tends to rise just as you have indicated. Looks like you have a good eye on it as well as everything else. In veg ppm and ph are just going to do that. I would have stuck with the HPS light as they will need to get use to it like u said, before they go into bloom. When you add the extra light in your grow room, watch you res temps, you dont want them to get over 70 or you could have root rot. Also like you said, more light, more heat, more humidity, so watch that when you get into bloom as well. Hope all is well and this helps.-PuttPutt