Nutrient Film Technique Water Recycling

kraythe

Member
Greetings. First off, I am not growing Cannabis but you guys seem to know a heck of a lot about growing things especially indoors so I thought I would ask you all a question. It was an interesting ride to get here, I am a vegetable gardener and wouldn't smoke weed personally but then I am also a libertarian and so I think people should be allowed to ingest what they wish. At any rate I found this site and a ton of information on hydroponics so I thought I would make a post.

I have previously done drip systems but I am looking to get a better yield on my crops so I have set up a 154 site NFT system as a test bed. The system is pretty standard NFT fare with water/nutrient solution pumped up into small tubes that feed the grow tubes and run down to the gutter which collects the runoff and sends it back to the reservoir.

The question relates to handling the nutrient solution routine. I know that after a week or two (depending on the plant) the solution will be depleted of nutrients and need to be refreshed. However, with a 40 gallon nutrient tank that seems to be a bit of a chore and a water wasteful one at that. I know the plants will take up some of the water but I will still be looking at changing out 35+ gallons every two weeks. So I am wondering if there is a way I can conserve time and water at the same time.

Is it possible for me to, instead of ditching all the water, simply re-add nutrients to the water in the correct amounts and keep the solution going? The other idea would be to pump the solution through a reverse osmosis filter that would clean the water and into a new reservoir container and then re-add nutrients. If either of these is possible, is there a way to measure the nutrient level in the water. I know there are TDS meters but they seem to give only total dissolved solids and I am concerned that if plants take up more of one nutrient than another, I could be starving the plants of a critical nutrient (assume for example that i would really need to add more nitrogen than other ingredients but I am adding the entire nutrient to the water creating a surplus of other nutrients.)

All comments and suggestions are welcome. My goal is simply to use the water as much as possible.

Thanks for your time.
 

hellraizer30

Rebel From The North
As dirty as nutes are a ro system wouldnt last long at all. With nft you shouldnt need such a large res tank!
You might look into going smaller.
 

phillipchristian

New Member
I don't see a way that you will be able to reuse the water. You would need a large commercial grade filttation system that would be cost prohibitive. If you are worried about the tedious chore of emptying your res then just get a hydro pump and connect tubing to it. Drop the pump in your reservoir and drain the water to wherever. I also agree with you that it would near impossible to know which nutrients were being uptaken in higher quantities. Best of luck man. Maybe check out the Gardening section. They might have some idea there.
 

^Slanty

Active Member
It really depends on which nutrients you are using and how familiar you are with them and growing. I have run several NFT runs using GH 3 part and not changing the reservoir for the entire bud cycle(8-10 weeks) By using my PPM meter, I just topped up the reservoir with water every day, and topped up the nutes twice a week.

Now keep in mind that I do have exceptional water, and keep my temps below 65* at all times which helps a lot! This will not work for everyone, but all you can do is try! You may be able to go 3-4 weeks or more!
 

Serapis

Well-Known Member
I'm with slanty on this one. You can probably go longer than 2 weeks. You may also find a use for the water outdoors in flower beds, etc. I use a top drip and just keep topping the water off without changing it out, except for the last 2 weeks.
 

RavenMochi

Well-Known Member
I'm with slanty on this one. You can probably go longer than 2 weeks. You may also find a use for the water outdoors in flower beds, etc. I use a top drip and just keep topping the water off without changing it out, except for the last 2 weeks.
Whats up Serapis, been awhile? How've you been? :blsmoke:
 
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