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Three types of hydro in a small tent on one airpump?

Discussion in 'Hydroponics / Aeroponics' started by Larry3215, Mar 4, 2018.


    Larry3215 Active Member

    I have decided to try an experiment for my second grow – which will also be my first time doing hydro. I know, probably a crazy idea, but I like to tinker around with new things and this sounds like fun and it wont kill me if all the plants die [​IMG]

    Im going to run three different types of hydro, at the same time, in the same small tent, on the same rez - using only a single air pump.

    If anyone is curious, this all started with this thread:


    So, why three kinds of hydro at the same time? I’ve been reading a ton of hydro threads, and it occurred to me that the only real difference between the different types of hydro is the ratio of air to water at the root level.
    At one end of the spectrum are things like DWC, water farms, hempy buckets, etc., where at least a portion of the roots are completely under water 100% time. The % that is above/below the water varies, but at least some portion is fully submerged 100% of the time.

    Then there are things like EBB/flow which change things up on a cycle – lots of water then no water, then lots of water. I think they fall more or less in the middle.

    At the other end are NFT systems and hi-pressure aeroponics, fog-ponics, etc., in which the roots are never completely submerged. They are mostly in the air with just a constant thin film of water or micro droplets.

    Also at this end is a relatively unknown (to pot growers) new type of hydro called Membrane Meniscus. It is basically just an extreme type of NFT with even less water contact at the root level than a typical NFT or aeroponics setup.

    Each type has its proponents and detractors, and success, and failure stories. People have been successful with every type of hydro – but which is “best”? I have yet to see anyone who has done side by side grows where the only variable was the type of hydro.

    Im bored, I like to fiddle around with new (to me) tech, I have a bunch of seeds from a single plant, and it occurred to me I could actually fit three different types of hydro into my small tent with very little effort, and very little cost – so why not?

    I don’t really expect to see a huge difference between the three types Im going to do, but I wont know until I try it. If there is any significant difference, I have my money on the Membrane Meniscus. It has the potential to provide the highest air to water ratio of the three types Im going to try.

    Im going to be running three 5 gal totes side by side in my 7 sq ft tent. All will be growing the same seeds, started in the same medium (perlite), under the same LED lights, using the same water with the same nutes from the same rez.

    So the only variable will be the ratio of water/air the roots get based on the type of hydro running in each tote.

    Tote 1 will be ebb/flow (highest ratio of water to air) – with three twists.

    First, the ebb/flow cycle will be a constant loop. It will run 24 hr a day, 7 days a week. Most ebb/flow setups I have seen go longer between fills and many only fill/drain during the day. So this setup will be closer to a DWC as far as water/air ratio than most ebb/floe setups.

    Second - It will be regulated by an automatic siphon (that costs less than $2 to DIY) inside the tote – no timers or submersible pumps in the rez. There will only be a single aquarium air pump that drives an airlift pump to deliver the water. It will take aprox 30-40 minutes to fill the tote. Once the water level gets hi enough, the siphon will automatically trip and the tote will empty in aprox 2-3 minutes. The cycle will immediately start over and repeat as long as the airpump is running.

    The third twist is the media I’ll be using. Im going to use a mix of lava rock and small pieces of scrap plastic pipe for the main media. The plastic pipe pieces are to save on weight, and to create voids in the media to make extra room for more root growth. Im hoping to get a larger root mass that way. At the top of the tote will be a small container of perlite to start the seedling. It will probably be a 2” long piece of 2” PVC pipe filled with perlite, just sitting on top of the lava rock mix. The reason for the perlite is so all the seeds start in the same way in each tote. Each one will have perlite for the seeds to start in.

    Tote #2 will be the NFT tote – again with a twist. Im going to be running the water film through a thin fabric mat on the bottom of the tote. The roots will grow into that mat as the plants grow. This tote will also have a PVC pipe, drilled with lots of holes and filled with perlite, extending up from the mat to the top of the tote. There is a video in that other thread I linked to with details on this. This tote will be the middle ground as far as the ratio of air to water exposure for the roots.

    Tote #3 will be Membrane Meniscus – the absolute minimum water/maximum air in the root zone. Again, the theory and details are in that other thread.

    All three totes will be insulated from the grow tent as much as possible to help reduce rez water temps. All three will be getting their water from the same single air pump driving the same single airlift water pump. Most of the water will go into the ebb/flow tote with smaller portions divided off to the other two totes with the Membrane Meniscus tote needing the least amount of water. That same air pump will also aerate the rez with some DIY air “stones”.

    Im about 2 to three weeks from harvest on my soil grow. I’ll start the hydro project as soon as possible after that. I will be building out the totes and rez as much as possible over the next several days and I’ll post pics as I go along.

    There is actually a second thing I want to test with this grow. Im curious to see which method gives the best harvest, but Im also wanting to see if any of them gives a significantly larger root mass. Its been suggested that larger roots make for larger harvests. Id like to see if there is any truth to that.

    As always – questions, comments, suggestions, corrections, etc., are welcome!

    JSB99 Well-Known Member

    Sounds interesting. I've built a few different hydro/aero setups. I found that DWC, with a powerful pump, results in explosive veg growth. I've seen 3" to 4" in a single day! That's why it's my permanent system :)

    JSB99 Well-Known Member

    These rooted about 3 weeks ago, and I moved them in the tent just two weeks ago! The girls on the right are White Widow. It's hard to beat DWC! All that water keeps things very stable!

    Lordhooha, kingtitan and Larry3215 like this.

    Larry3215 Active Member

    Thanks for jumping in. Your babies sure look happy and healthy!

    From what I have seen, DWC, in one form or another, seems to be the most popular technique - at least it gets the most threads and posts. Its hard to tell if thats because it works better or because its fairly easy to set up.

    Im going to be doing this with regular seeds.

    It would have been best if I was able to use clones - especially fem clones, but I dont have access to any clones or even a mother I know I would want to grow again.

    Second best would have been all fem seeds, but again, I dont have a set of all fem seeds I want to grow right now, so Im stuck with normal seeds. If they all sprout, Im going to start 6 seeds - two in each tote, then cull the males as soon as possible. If I am really lucky, I will end up with at least one females in each tote. The odds are against me though, so I will likely have to move some plants around - which will further cloud the results. Hopefully I can identify the males early on.

    All of that will muddy the results to one degree or another.
    JSB99 likes this.

    Larry3215 Active Member

    Ok, here is the first set of pics. This is the airlift water pump. It works the same way an under gravel pump works with an air stone. Air is forced down the outer pipe, then forces water up the smaller inner pipe as it flows up and out the top. This has the advantage of also forcing fresh air into the totes as it supplies them with water.

    0128181255.jpg 0128181255a.jpg

    and this is the auto siphon I decided to use. It seems to be the most reliable with low water volumes. This has the attached P-trap that will be below the tote. I may do away with the trap after some more testing.


    This is what it looks like inside the tote. . Im still working on a final design for a shield to keep roots out. I'll add that later.


    Here is the trap on the bottom of the tote.

    Lordhooha and JSB99 like this.

    Larry3215 Active Member

    Here is the progress on the NFT tote so far. Ive installed a drain manifold and placed a screen made from silk screen fabric over it to hopefully keep the roots out. I will be watching this carefully as things go along.

    The manifold is just a series of small holes in the bottom of the tote just large enough to force some airline tubing into. All 4 airline tubes feed into a 1/2" CVPC pipe that will drain back into the rez by gravity. There were no signs of leakage when I tested this, but Ive sealed it all up with hot glue to hold it in place better and to stop any future leaking - I hope :). If it does leak, I have some 3M 5200 fast cure Marine sealant I can use.

    Im going to try to get this all done with zero bulkheads or grommets... we will see....





    Larry3215 Active Member

    Here are some shots of the plastic pipe pieces and how they look mixed in with the lava rock. You can see the extra voids the plastic pieces create between the lava rock. The lava rock is a lot lighter than regular aggregate, but still a lot heavier than hydroton. With the rapid cycling I will have I think this will work just fine. Turns out I had more than enough short scrap pieces of pipe laying around to do this. Its a mix of 1/2" PVC and CVPC and 3/4" PVC pipe.



    JSB99 likes this.

    kingtitan Well-Known Member

    Nice, I love DIY stuff man!

    Also find some JB Water Weld, used it in my filled hot tub right at the bottom, no problem, I was amazed. Works in 5 minutes, even under water!
    JSB99 and Larry3215 like this.

    Cold$moke Well-Known Member

    Im in

    i made a mini mock up of MY meniscus nft system :) plants are vegging currently
    JSB99 and Larry3215 like this.

    eyderbuddy Well-Known Member


    thanks for sharing the luv
    Larry3215 likes this.

    JSB99 Well-Known Member

    I found that bulkheads are worth the small investment. I made my own for a long time, and often end up fighting drips. They're fairly cheap on Amazon.

    Cold$moke Well-Known Member

    I found the same thing :)

    Although i was impressed with how long my hot glue job held up lol
    JSB99 and kingtitan like this.

    Larry3215 Active Member

    My fingers are crossed on leaks... :D
    JSB99 likes this.

    JSB99 Well-Known Member

    Get a tube of aquarium-safe silicon. It'll come in handy.
    Nugachino, Larry3215 and Lordhooha like this.

    Lordhooha Well-Known Member

    Love the dyi.
    Larry3215 likes this.
    Budley Doright

    Budley Doright Well-Known Member

    If that is silkscreen as a root barrier it should work great unless it plugs up. I use it on my ebb and flow drain and I need to rinse it once half way through a run but much smaller area :).
    Larry3215 likes this.

    Larry3215 Active Member

    I have a tube of 3M 5200. That stuff is rated for below water line use on boats and lasts forever. In fact, I just used some to install a heat sink on the side of the rez.

    I added a heat sink on the side of the rez for the future addition of some peltier coolers if the rez temps get too hi.

    I think peltier coolers are very 'cool' gizmos and Im actually half way hoping I need to buy some to keep the rez temps down. They are cheap and easy to work with. The cheap ones dont have perfect reviews, but it will still be interesting to try them out to see how effective they can be at cooling. One of the best features is that by simply reversing the current flow you can heat the rez or cool it. I have an STC1000 temp switch that can do the switching automatically. I will be using it to monitor rez temps and - if needed - control the peltier coolers.

    Amazon.com: Laqiya 5PCS TEC1-12706 12V 60W Heatsink Thermoelectric Cooler Cooling Peltier Plate Module: Computers & Accessories
    100% Brand new and high quality Get ice cold in minutes or heat to boiling by simply reversing the polarity, used for numerous applications from CPU coolers to alternate power sources, or even for you ...

    This heat sink I added has room for 4 of them if needed. This is just some scrap aluminum channel left over from other projects - including my Solstrip light fixture. I will attach the cooler modules to the heat sink on the outside of the tote, then attach another piece of the channel to them and add a computer fan for cooling. I have several power supplies from my RC hobby that can run them, so it wont cost much to do this. These can be had for even less on ebay.

    All I did was cut out a strip 1.75" wide by 7" tall, then glued the heat sink in with 3M 5200 fast cure marine sealant. That stuff will last forever and not leak.


    The garden spigot is to drain the rez and the 1/2" CVPC pipe is to feed the airlift pump chamber. I'll go over that later when I get to that part.
    Nugachino, Zero_OS and JSB99 like this.

    Larry3215 Active Member

    Yeah, I got the idea from you - thanks!!
    Budley Doright likes this.
    Budley Doright

    Budley Doright Well-Known Member

    Glad I could help, great project! Good luck, hopefully no leaks.
    Larry3215 likes this.

    Larry3215 Active Member

    I am having doubts and reservations about the Membrane Meniscus technique.

    I decided to run some more tests based on how I plan to setup the Membrane tote. I have been planning to follow the original patent drawings and details pretty closely.

    That would be a layer of perlite in the bottom of the tote, with a water inlet on one end and a drain on the other end. The nute solution is supposed to flow slooooly through the perlite. The water level needs to be just at or barely below the top of the perlite. The, the "membrane" sits on top of the perlite. Its purpose is to allow water to wick up to the root zone but prevent the roots from getting into the perlite. The roots are NOT supposed to be sitting in water. Only a thin film of water - the meniscus - is supposed to be touching the roots.

    That all sounded good to me, and when I ran my first test of the rip-stop nylon I have using just water, it seemed to work fine. That test was just filling a jar to the top with water and setting the nylon on the top and then placing a cardboard tube on the nylon and seeing the water wick up the tube. That worked ok, but the water was actually touching the nylon in that test.

    I put some perlite in a jar and added water almost to the very top of the perlite. Then placed the nylon on that and stick another cardboard tube in there with a small weight to hold it against the nylon and perlite. Wicking does occur, but it is really sloooooooooooooow. Im having a hard time imagining this will be enough water to let a plant grow properly.

    So I ran a second test using the silk screen. It lets water flow through it very freely where the nylon does not. The wicking action is much better, but its still pretty darn slow.

    It looks like my nylon just doesnt wick fast enough to work, so maybe I have the wrong kind of rip-stop or its too dense or something. The silk screen however, is a lot more porous than what he describes as the perfect material - I think.

    Im going to have to go re-read his notes and details to see if I missed something. If it wasnt for the rave reviews I read and pics from several different growers, I would doubt this could possibly work. Actually, Im doubting anyway....

    Left is the rip-stop and right is the silk screen after about 15 minutes.

    Cold$moke likes this.

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