GT205 NFT setup and fertilizer questions

[Z-Beeblebrox]

Hi all

Before all my questions are spread around in other treads I thought that I could try to get some comments on my setup.

I have setup a GT205 under a 250W CFL (6500K) running 16/8 placed 1½ feet from the mat.
I have 6 seeds sprouting in a paper towel and have placed 6 1"x1" Grodan blocks on the mat. When the seeds are sprouted, the plan is to place them in the Grodans and let them grow.

The tank holds 20L water:
I have mixed RO water with tab water so my basics hits:
N:K:Mg:Ca:S - 0:50:70:6:60:20

To that i have added nutrients to
N:K:Mg:Ca:S - 65:50:130:35:60:20
This gives me an EC of 0.8mS/cm and I have adjusted pH to 5.9 with phosphate acid and the reservoir is heated to 23°C. This solution will be on for the first 2 weeks.

So initially I would like some comments on the way I'm growing the seedlings and about my nutrients for the next 2 weeks.

Is there anything I should add/lower, do different?

 

[Ursus]

Very clean set up mate it seems you'll be having no problems. Your water mixture seems fine for the seedlings for the first week but after their second set leaves I would start adding small amounts of your nutrient. IMO CFL/Flouros are the only sensible way of vegging cannabis. Everything looks perfect though, just needs some seeds! btw nice pipe too, love those kind!

 

[Z-Beeblebrox]

So today all my seeds were sprouting and i popped them into the Grodans.

2 fem. DP Blueberry and 4 reg. Early Durban (Hoping at least 2 of them are females)

I'm having some problems with the pH, its going up every day and I'm adding some phosphate acid to lower it. I'm checking pH and EC twice a day.

 

[grow101]

The Grodans have to be aligned first, did you soak them in pH 5,5 water for a minute or so (Grodan has got youtube-videos online, the small blocks only need a couple of seconds) the rockwool has got a high pH if you don't do this. That shouldn't influence the whole 20 Liters IMHO. If you stay beneath 6,5 you are fine, even if you want to aim for 5,8. 250W seems a bit like overkill, as 50W would do so at this time, too. I like your setup, clean, but I already told you that

 

[Z-Beeblebrox]

Yeah I soaked them, and they have been on the gt205 for a day. I have considered less light, but I'm aiming for a low growth

 

[Z-Beeblebrox]

1 day after putting the sprouted seeds in the grodans I see growth
Can't wait to get home.

pH this morning was 6.0 , EC was 880µS/cm

 

[Scrogerman]

Nice clean set up, the only way to do it indoor. Whats nutes you using? I shoot for PH 5.5-5.8, for starts at PH 5.5 in RW as Grodan recommend themselves. I usually use Ionic for starts & early Veg(1/4 strength), beats any start product IME. look forward to seing more man!

whats the PH & EC of your base water(before you add nutes/RO+Tap)?. small tanks like the 205 are gonna need alot of attention, daily maintenence(more as they grow), thats the way it is with small recirc res's(esp under HID, not so bad with CFL etc), bigger Res's dont suffer the same issues for obvious reasons, plant uptake/evaporation etc.

Id bang in a 150w HPS or a 250wAC hood personally & Lst or Scrog for canopy control managment
Id use CFL to start off though.


G'Luck!

 

[ChaosCatalunya]

As Scrogerman said, a really nice clean setup, you seem to be well and truly on the right path...

Nutriculture's NFT tanks are great, I got my first hydro experience with them and never bothered with soil again. The only thing I would say, is, if the small noise is not a problem... trim your spreader mat a bit above the reservoir water's surface, so you get the solution oxygenated by the "waterfall" rather than letting it go straight into the solution below.

 

[Z-Beeblebrox]

I'm using basic ferts like KNO3, Mg(NO3), K2HPO4, KH2PO4 ect. and a micro powder (Rexolin APN).

The EC is and pH of the tap water is 0.8mS/cm and 7.6 respectively.

I have some surfactant (not detergent, but pure surfactant) to remove the surface tension. I'm gonna try to ad some soon.

I have already done the trick with the spreader mat. But I'm thinking of adding an air pump, also to increase the movement in the reservoir.

Btw. Its a two room closet!

 

[Scrogerman]

Cool bro soo neat, your mixin your own nutes, ill be following along then, luv NFT, its soo simple!
What is the total element profile of your mix man, & where did it come from? how you mix it up etc?

Cheers, G'Luck!

 

[Z-Beeblebrox]

I have based my ranges somewhat on the Cannastat nutrient profile and from inputs here on the forum

For the first 2 weeks my ranges are:
70:50:150:40:50:40 (N:K:Mg:Ca:S) (ppm)

Then I use Hydrobuddy to calculate the amount of chemicals to add per 20L.

I have KNO3, Mg(NO3)2,Ca(No3)2,KH2PO4, K2HPO4, and Rexolin APN

I dissolve:

4.19g KNO3
8.521g Mg(NO3)2
1.39g of Rexolin in some RO water.

For my reservoir i mix 50:50 tabwater with RO water, giving me about 60ppm Calcium and a little of some of the others.

Then I add 3ml of a 1M Phosphate buffer pH 5.8 giving me 50 ppm Phosphate.

Lastly I add the nutrient solution to the reservoir - almost all of it to reach 900µS/cm. That should give me the ranges before mentioned.

 

[Scrogerman]

You seem well versed on this, ill be interested to see how you get on, you have run this before?

 

[Z-Beeblebrox]

No - this is my first attempt at hydro ever. But chemistry is simple.

 

[DiscoBiscuit]

Wow, your grow #2 will be on the space station.

Did you customize a cabinet or build from scratch? Top notch design and application skills.

Looking forward to your progress.

 

[Z-Beeblebrox]

Thanks all. Look in the signature link. I made it from whole MDF boards using only hand tools.
I can't say I'm a fast worker, but I want the details perfect. Maybe not the finish, but definitely the details.

 

[ChaosCatalunya]

I'm using basic ferts like KNO3, Mg(NO3), K2HPO4, KH2PO4 ect. and a micro powder (Rexolin APN).

The EC is and pH of the tap water is 0.8mS/cm and 7.6 respectively.

I have some surfactant (not detergent, but pure surfactant) to remove the surface tension. I'm gonna try to ad some soon.

I have already done the trick with the spreader mat. But I'm thinking of adding an air pump, also to increase the movement in the reservoir.

Btw. Its a two room closet!

I admire your boldness and confidence in running your own nutes. A friend did years ago and we argued about it a lot, I always said it was better to play safe and go with a proven solution, a good brand hydro nute ...and maybe test other options by the side, he disagreed...

I see you know about doing it already for aquatic plants, so I guess it is more of a known quantity, it really is exactly the same thing, just under water...

You can get a nice alternative to a separate air pump by [maybe upgrading your submersible pump and] adding in a T piece just as the hose surfaces, an L to control the angle better, a tap to control the flow of the jet you angle down across the surface.

Looking forward to seeing this come along.

 

[Z-Beeblebrox]

Thanks for the suggestions Chaos -will definitely take them into consideration.

Update for now is: All plants grow very fast. +15cm roots from some of them, and I have soaked the big (7.5x7.5cm) grodan blocks and are planning to transplant the plants tomorrow.

The weather here in Denmark is great. Sunny and 26°C = great in Denmark. But the temperature in the cabinet rose to 32°C, so i vented the house and it dropped to 30°C. 3L evaporated from the reservoir and the EC rose to 1.1mS/cm. I added some 50:50 water and adjusted the pH so that the EC came to 900µS/cm and pH 5.9.

 

[Z-Beeblebrox]

1 week

1 week

pH 5.9, EC 920µS/cm

Just moved them to the big Grodans

 

[highonmt]

No - this is my first attempt at hydro ever. But chemistry is simple.

I love it nice set up man. Also, "Chemistry is simple" very Zen like statement to a professional chemist. Thanks for posting up your grow.
HM

 

[Z-Beeblebrox]

Update day 13:

Update day 13:

Thanks!

All plants are doing good. Compact growth and short internodes

Stems are strong and thick already

Sideshots grow fast

Roots grow healty