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

Indoor Growing Hydroponics
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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 :slight_smile:

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!

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Good luck! It will be interesting to see your results. Remember that the more variables you have that are new, the harder and longer it takes to fine tune a hydro system. You are brave and I hope it works out as you have in mind. I myself enjoy building different systems and it can get very frustrating, Don’t give up and don’t expect changes overnight is what I always tell myself.

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Thanks!

Your comments remind me of the old Chinese curse - May you live in interesting times! I expect to have at least a few interesting times with this grow, but at least I wont be bored! :smiley:

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I like it a lot. I know you will get some useful data from it. Especially when it comes to ease of use etc. :thumbsup: :seedling:

My only critique is you are using seeds instead of clones and low plant numbers on top of that. Statistical variation could come from genotypipic expression rather than hydro method. :thinking:

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I will enjoy watching. Always willing to learn and hopefully find something I can use to make growing easier.

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Yeah, I agree, using clones would have been far better, but I dont have access to any clones or even a mother I know I would want to grow again. Im still hoping this experiment will at least be an indicator of possible trends. It sure wont set any gold standards as far as which type of water/air ratio is best.

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.

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Ive decided I dont like reserving posts early in the thread for certian things, so Im deleting those posts and doing this the normal way :slight_smile:

Here are some shots of the airlift pump and the ebb/flow tote progress to date.

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This is the auto siphon Im going to use. I may or may not keep the P-trap on the bottom side of the tote. Depending on how the relative heights of the totes vrs the rez end up, I may not need it. The trap is a big help if you dont have enough vertical fall inside the siphon.

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I havent decided on a final design for the shield to keep roots out of the siphon. I’ll add that later, along with an over flow drain. It will need to allow me to check on the trap periodically to be sure its clear and working correctly and let me clean out roots if they get past the shield.

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Here is the progress on the NFT tote so far. Ive installed the 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…

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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.

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Hopefully, those extra voids will fill up with roots…

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I have to say that your “ebb & flood” sounds like a DWC or SWC depending on the water depth, but for sure it ain’t ebb & flood. So please don’t call it such, it will only confuse some newbies.

The project looks excellent and your building skills seem to be good - mine are shit, always just bought my systems…

The last system, why couldn’t you describe it here… I am old man no time to hunt for some other threads… Why not have the information in this thread as this is where you seem to be posting about this particular project…

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LOL I’m an old man too so I know what thats like :slight_smile:

I dont understand why you think its not ebb/flow? The tote fills up and then it drains out all on a schedule.

True, its not your typical pot growers ebb/flow - but - I found the info on the automatic siphons while Googling Ebb and Flow. Turns out that the automatic, or Bell siphons, of various types, are used in Ebb/flow setups quite often - all over the world. In fact they have been in use sinse at least the early 1800’s in hydroponics E/F setups. Everything from small personal gardens to huge commercial growers. In almost all of those cases, the ebb/flow rate is controlled by the auto siphon and runs continuously, just like Im doing. There are a few I saw that turned the pump off at night but only a few and for certain plants. Most just set it up and forget it until harvest.

Try Googling Bell siphon, and look at some videos. There are dozens. Almost all of them are in relation to or being used in ebb/flow setups of one type or anther.

This is nothing like a DWC where the roots are fully submerged in the water 100% of the time. As far as I know, SWC is just DWC with shallower water, so again, nothing like this.

I am happy to post the info on the Membrane Meniscus setups for you.

It is a system developed several years ago by an engineer from Australia, who happens to love hydro as a hobby. All the reviews I read were raving about how well it works compared to other types of hydro.

Here is an article about it.

https://www.maximumyield.com/membrane-meniscus-method/2/1498

Here are the patent drawings of the setup. Im going to change a few of the details up a bit to use materials I have on hand, but it will be very close to this in function.

And here is the patent application with additional details on materials, function ,etc.

miniscus.pdf (1.1 MB)

There is a later book he wrote with tons of extra details, theory etc., but its too large for me to attach the file. He revised some of the details as far as recommended materials, and made it a little more complicated after that patent drawing, but again the function is the same. If you want to read it, you can try this Google Docs link…hope this works.

I will cover the details of how I am going to do it when I start working on that tote. Should be in the next few days.

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Great topic, I’ll be following it…!

Btw. how do you plan to cover your root zone? I was using foil but was not satisfied with inability to move plants after…

Don’t want to argue but isn’t that 24/7 constant loop is exactly what differs NFT systems from Ebb&Flow. Lack of dry cycle makes it completely different system imho.

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Yes, in ebb & flood the container should be filled, and then have a dry cycle inbetween another filling. If its not going dry at any point its not going to be ebb & flood.

But I don’t know, this is one of those “arguing in the internet” moments…

Just do your thing and call it whatever, man… :smiley:

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Hi there!

Please take a look at this Article, maybe it can help you with your choice of growing in water or soil.

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I hated my diy ebb and flow attempts, so many problems with blocked filters, drains, pumps etc. With constant recirculation setups pump and pipe size is important, a large flow rate can produce amazing yields so the bigger the better and less problems with blockages too.

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Roots blocking drains has been one of my worries from early on. From all my reading, it is a major problem for many hydro growers in many different types of systems. Someone on another thread mentioned that they had finally found something that was pretty good at keeping roots out - silk screen fabric.

The silk screen idea fits into one of the main ideas behind the Membrane Meniscus system - the “membrane” he uses has to keep roots out of the chamber where the nutes are flowing. At the same time it needs to allow water to wick through the membrane so the plants can feed.

The materials he recommends are ripstop nylon (parachute material) or tightly woven polyester fabrics - like shower curtain fabric. I have some of both fabrics and tested them for how well they wicked water. They do well at slooooow wicking but the flow rate is too low to use them as a drain screen.

I plan to use the silk screen fabric to cover all drains and water inlets where the roots can reach. Hopefully, the roots wont be able to attach to the silk screen or get through it.

Just in case - Im also going to do my best to make it so I can look at the drains and potentially clean out any roots that manage to get past the screens. Im still playing with options on all that, but I will post what I come up with.

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Thanks for the information. I will look at that after bfast and some more coffee :slight_smile:

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Moving plants has been a worry of mine too. Especially since I would really like to do scrog again. It occurred to me that I cant really move these guys anyway once the roots get going good, because the drain and fill pipes will all be in the way. My plan at the moment is to just put up with not being able to move them. Thats how it was with my soil grow once I started training into the scrog screen.

As far as covering the root zone - based on my reading so far, I think thats going to be an important issue for two main reasons.

  1. Controlling temps in the root zone and the rez.
  2. Keeping algae growth out of the growing medium.

My plan at the moment is to isolate the root zone from the grow tent as much as possible. I plan to use 1" thick pieces of foam insulation board that I have on hand (left over from building a curing over for my glider models vacuum formed carbon fiber wings - my other hobby).

The totes will be set into cutouts in the work bench top my grow tent is sitting on so that most of the tote is below the top and out of the grow tent. The portions of the totes that are in the tent will be wrapped in insulation board on the sides and have removable lids mage from the insulation board and the tote lids.

Im then going to cover at least the top parts of the foam with left over pieces of the reflective mylar film that I made my tent from. Im going to seal the mylar around the plant stems as much as possible to try to keep the warm air in the tent from getting down into the root zone. Im worried about rez temps getting too hi and dont want to add a cooler unless absolutely necessary.

All the totes will have holes/vents cut in them so that they can draw fresh, room temp air in from under my work bench and not from the grow tent. This time of year my spare bedroom stays in the mid 60’s F while my grow tent stays in the upper 70’s. Im hoping to keep rez temps in the upper 60’s.

Those are very good questions guys, but b ased on some tests I ran a few weeks ago, I dont think there is as much “drying out” as you think. Unfortunately, I didnt bother to take detailed notes or get pics, so I will repeat the experiment now and report results over the next day or so.

What I did was get some perlite and some lava rock wet, then tested them both to see how much wicking they did. I also looked at both under my new USB scope to see what they looked like wet and dry. Both wick water pretty well, but perlite is much better.

The interesting thing to me was how long they took to dry out when looked at under the scope. It was a looooong time. I forget exactly but after at least a full day, both still looked wet under the scope.

So, Im going to repeat those tests now and keep notes and report back.

For starters, lava rock holds about 7% to 8% water by weight when you soak it for a few seconds, then shake off all the excess water.

Perlite on the other hand, holds about 185% water by weight when you do the same thing. Huge difference.

Unfortunately, I dont have any hydroton to test, but I suspect it will be somewhere in the middle.

I have a sample of perlite and lava rock drying now and will check weights and look at them under the scope over the rest of today and see how long they take to dry out just sitting out in my room.

Also, keep in mind that most NFT setups are covered so they dont dry out.

On the other hand, most ebb/flow tables, at least in large grows, are not covered, so they will tend to dry out more given enough time between fills. I just dont think there is as much drying as most folks think.

Plus - like I said above - most of the rest of the hydro world cycles their ebb/flow setups just as often as I plan to do it. Its pot growers who are the odd ball minority :slight_smile:

All of that said - I dont really care what you call it or if this is “true” ebb/flow or not. The main purpose of this test is to see if the ratio of water to air in the root zone makes a significant difference in grow rates and yield. Cycling the ebb/flow tote this often will put it at the hi end of that spectrum as far as submerged water time. DWC would be higher yet, but I dont have room for another tote in the tent :slight_smile:

I think grow rate/yield vrs water/air ratio is going to be the main take away here - I hope.

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I forgot one more point.

Some folks claim the DWC is “best” and some claim that hi pressure Aeroponics/Fog-ponics, or NFT are “best” while the Membrane Meniscus guy claims that even less water is the “best”.

As far as Im concerned, the only real difference between those systems is how much time the roots spend submerged or really wet vrs just being wet with a very thin film. Thats what Im trying to test.

The ebb/flow will be my “wet” tote. The NFT will be in the middle and the Membrane will be the “dry” tote.

If it turns out that the “dryer” setups work better, then it might be good for ebb/flow folks to have longer dry times than wet. On the other hand, if it turns out more water is better, then they might consider trying more cycles with longer wet times.

Hopefully, we will see :slight_smile:

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More water carrying nutes and oxygen is usually key to big yields. Maybe you have seen his posts but if not, google search - Heaths Latest Tree Grow.I would put up a link but i don’t want to upset the moderators by placing a link to IC, especially as i only post here. Heath Robinson is something of a legend, he regularly produces massive hydro yields with only 1.2 EC feed level. He apparently pumps as much as 1000L per hour through his buckets and says that is key to huge yields. A

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