NFT grow - Leaf problems

[tsakalos]

Good morning to all of you. This is my first attemt for indoor grow with a nft gr424 but from the beggining i am facing different problems possibly with overfertilizing.
My grow room is 1.2 X 1.2 X 2m . I use an HPS 600W Lumatek full spectrum with a dimable Lumatek ballast.
Ventilation is provided by a profan extractor 125mm 220-270m3. Room temp vary from 18 to 24 celcius and the water is stable at 20 degrees.
Ph is usually between 5.2-6.3 and EC is no more than 950 (600 is from my water hardness). My ferts are canna aqua and i am using the:
cannazym, rhizotonic, vega A & B και flores. Seeds were spooted 1/12 and i have 3 Green poison and 1 jack herer all of them photoperiod. Right now, a month after my plants height is 13 to 18cm, still running 18/6 and i am thinking this weekend to switch to 12/12. Pictures are following. Any advice on what can problem be is more than welcome!

 

[tsakalos]

 

[Scientific]

> possibly with overfertilizing
The leaves are hooked (or "clawing"), which is a symptom of too much nitrogen. You should be giving small plants much less fertilizer. (Manufacturer's recommendations tend to be very high.)
600 PPM water hardness is "liquid concrete, so I'm guessing you are adding a lot of pH Down? What is the pH of the water from the tap? If your water is really 600 PPM, you would do well to buy a reverse osmosis device or buy RO water.

 

[tsakalos]

600 PPM water hardness is "liquid concrete, so I'm guessing you are adding a lot of pH Down? What is the pH of the water from the tap? If your water is really 600 PPM, you would do well to buy a reverse osmosis device or buy RO water.[/QUOTE]

The water in my area is between 550-600 EC and the PH 7.1 to 7.2. I usually add 2ml of phosporic acid per 10lt of water. Is the reverse osmosis device going to help?

 

[Scientific]

600 PPM water hardness is "liquid concrete, so I'm guessing you are adding a lot of pH Down? What is the pH of the water from the tap? If your water is really 600 PPM, you would do well to buy a reverse osmosis device or buy RO water.

The water in my area is between 550-600 EC and the PH 7.1 to 7.2. I usually add 2ml of phosporic acid per 10lt of water. Is the reverse osmosis device going to help?[/QUOTE]

I take it your reading EC in micosiemens and not millisiemens (which I believe is more commonly used here, though PPM is used most of all...)

So 250 PPM then? (When you said "600" I assumed PPM, not uS).

That's still hard water--hard enough so the General Hydroponics recommends using their special FloraMicro Hardwater formulation at that level. The manufacturers assume that you're using pure water to start with, and all that "stuff" in your water (probably carbonates) does compete with the fertilizer salts.

The proof is in the pudding. If just dropping the pH with H3PO4 is working for you, that's OK.

Probably the best bet is to email your fertilizer manufacturer at their website and get their advice.