Adventures in Hydro #2 - LP Aero/NFT mash-up - or - switching to HPA?

Indoor Growing Hydroponics
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Ive been doing more cardboard testing today.

I didnt do the plastic nozzles, so this is just for the two types of SS nozzles.

The Aeromist are the pin type, and they have a fairly dramatic variation in the mist pattern. Mostly it looks like there are two or three, or more, major lobes to the spray where it is heavier, but its not consistent from one nozzle to the next or from one cycle to the next, and it changes with pressure. Every once in a while, the mist patter looks nice and circular and is obviously a “hollow cone”. However, the pattern is more normally several, uneven blobs of heavier spray with lighter spray in between.

I can only assume that variable nature of the pattern is due to the pins having some freedom of movement which changes the flow in the nozzles, which in turn changes the pattern of the spray when it exits the nozzle. It could also be very fine bits of crap getting jammed in there from time to time.

Each of the pins has three very fine grooves etched on the end of the pin where it butts up to the orifice. Im guessing these are to allow the water to get by the end of the pin more easily, but the gap is very small, and the pin has room to move lateraly.

Looking at the spray by eye, these look to have maybe a 90 deg cone angle, and roughly a 12" to 15" throw.

The EchoLogic nozzles are quite similar to the Aeromist in that they also have lobes where the spray is much heavier. but they are not as dramatic. In other words, the mist seems to be more evenly distributed. Its hard to tell for sure with these, but the cone looks more ‘solid’ than the Aeromist. They still seem to lean to the hollow side over all.

The cone angle looks narrower - maybe 50 deg, but the throw is about the same.

Ive adjusted the nozzles so the outer edge of the spray pattern just barely hits the net pot at the edges. I dont want to get the roots too wet with a direct spray, but I dont want to rely purely on scattered, randomly floating small droplets either - especially not at first.

I’ll keep it this way for a while after I put the seedling in the system. I’ll decide on changes/adjustments after the roots get adjusted and start to grow new shoots.

Im going to start with a heavy spray cycle at first = 0.7/30, until they get settled in. Then I will start trimming it down.

Im re-filling the rez, and adjusting PH, chlorine, and nute levels now. I expect to put the seedling in later tonight. Im going to start at 5.8 PH, 0.5 EC, and around 2PPM chlorine.

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She is all tucked into the root chamber of horrors. Lets hope she likes it :slight_smile:

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The black plastic is a cut up garbage bag. The orange lid with the hole cut out is to help seal things up. The idea is tp keep the net pot from leaking air or light.

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Oh, after seeing that last pic I lowered the timing to 0.5/35. Im checking every hour for the next little while to be sure she doent dry out. Im ok with her being too wet for now.

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I forgot to post the results of my balloon powered linear accelerator experiments. Turns out it was a non-starter :frowning:

I tried getting a video of what happens when you put a static charged balloon into the root chamber when its filled with mist. That didnt work well at all. Even watching closely in a pitch black room, I couldnt see anything that looked like a for sure reaction to the balloon. The mist may have wanted to move away from the balloon, or it could have just been air movements disturbing the mist.

So, later I found an old wool sock and tried rubbing it on a short piece of PVC pipe. That produced a much stronger static charge, nice snaps and crackles, but still no obvious reaction from the mist. This time, its just possible that maybe, possibly, it could be, perhaps, that some small amount of extra mist was attracted to the PVC pipe - maybe. Which is just the opposite reaction I thought, maybe, possibly, I might have seen with the balloons.

So, it looks like using static to powder coat the roots with mist isnt going to work - maybe. I didnt try reverse charging the root chamber, or the nozzles at the same time. Maybe after this grow.

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I need to look into the whole aeroponics thing. I need to know more ways to abuse my plants :stuck_out_tongue:

Some people just didnt get beat up enough in middle school

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hahahahaha!! If you really are my long lost twin, then yup. Aero is for you - its the least boring way to grow that I have tried so far. Of course, that also means its the most trouble! :smiley:

Actually, I think trouble is the wrong word. It is the most technical way to grow would be a better way to say it. Potentially, its also the highest yielding and fastest way to grow - or so I heard on that webnet thingy somewhere :slight_smile: I havent proved that yet with my growing, but I havent actually let any of my plants live long enough to tell :smiley:

@SuperiorBuds has said that he is getting much higher yields. Cant remember what he said about grow times for sure, but I dont think he saw a huge reduction in time? Dont remember for sure.

Low Pressure Aero is the easiest and least expensive as far as parts and setup. The only real downside is you will have to recirculate the rez - with all that implies about balancing PH, EC etc.

HPA is next up the scale. Here is where you can start to see those fuzzy roots, and where you’re supposed to start seeing noticeable improvements in yield and time. If you can get an HPA system dialed in. so you have low enough flow rates, you can do drain to waste and still save money. That also simplifies rez maintenance, and time required for maintenance.

That all assumes you can get the system dialed in, and THAT assumes you have nozzles that produce the correct size droplets with a decent hang time. Nozzles are the heart of the system. Without nozzles that produce a quality mist, with droplets in the correct size range, you’re just going to end up with LPA roots. Not that LPA roots are bad, but they are a step down from the fuzzy kind.

Thats my main beef with Atomizer. He refuses to share ANY nozzle info. He’s good about general theory, and he will jump in and tell you where you screwed up - after you have spent money and time on the wrong stuff, and its too late. He is really good at that.

The top of the aero scale is AA, or Air Atomized aero. AA can give you the most uniform mist quality, and it is the most tuneable or adjustable system. You have almost total control over flow rates, droplet size, throw distance etc. You can dial in an AA system much better than any other type of aero. You also have the potential to have the lowest flow rates, which will save $$ and allow you to do drain to waste easier and cheaper.

The problem with AA is that no one - especially Atomizer, who is the king of AA - will give you any clues as to which air atomizing nozzles to buy. There was a long thread on RIU a few years back where they were doing some of the earliest development, and refinement of HPA, and AA. Atomizer, and two or three others all decided NOT to share their HPA or AA nozzle information with the rest of us lowlifes. I can only assume they did that so they alone would stay at the top of the heap and remain the unchallenged “kings” of aero.

Once again, the nozzles are the heart of the system. If you have crap nozzles, nothing else matters. Decent AA nozzles start at well over $100 EACH, so its not the kind of thing most folks can just take a wild guess at, and risk throwing away several hundred dollars at a time if you guess wrong. I certainly cant afford that kind of risk.

IF you knew which nozzles to buy, setting up an AA system would actually not cost that much more than the cost of a good HPA system, and potentially much simpler as far as parts count, and plumbing.

As far as the theory, the goal is to provide the roots with a constant, unchanging supply of nutrient droplets that are just the right size. You dont want a wet cycle followed by a dry cycle. You want it just right all the time, so the roots are never starved or drowned. If you get it just right, they will have the perfect (according to NASA) supply of nutes and O2 at all times.

You can get close to that with HPA with some work. AA would be a good bit easier to produce that perfect environment, but there is the whole $$ nozzle thing.

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Well, fuck that guy. Nothing pisses me off more than somebody who buys off-the-shelf parts and does not share the part number. If he turned his on his own lathe and did not want to disclose the taper, orifice, overlap, and spring constant, fine, but i bet you anything it all came from an online retailer.

Do you know the cycle required, and the size of the droplet? I browsed through RIU – one smug motherfucker. I know nothing of HPA, but i know quite a bit about fuel delivery in industrial diesel engines, and i bet you six of your favourite beers AA is no more complicated. It’s AT MOST 12 steps.

I’m getting on board, fuck it. Gonna go do some research.

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Oooh. Now we are talking. HEUI “fuel” injection! :wink:

Ahh, ignore me. You’ve got me fantasizing. :stuck_out_tongue_winking_eye:

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@Northern_Loki, i am a true masochist, in HEUI I have owned 1x 7.3, 2x 6.0s and cats 3126 (both generations).
If i can make a six-litre squirt good, I can make AA squirt good too.

EDIT
But really, common rail is the way to go…

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How cool is that! That’s some heavy duty gear for driving around town :laughing:

Worked on the Cat ECM design team circa late 90’s or thereabouts. Only reason I even know what HEUI is :laughing:

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Sorry for the interruption Trichome Dome contestants, carry on.

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That kind-of sounds like RIU in general. I don’t get it.

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I dont want to get much more off topic, but yes, my wife and I used to contract for site overlay design and deployment at special events - temp power, structural, etc. Generators, trucking… did a good chunk of 2010 Vancouver Olympics. Burnt a LOT of diesel over the years :wink:

On topic though, one of the pioneers in air assisted spray (spraying systems co) has an office on Annacis island, right in my backyard. I’ll be taking advantage of that :wink:

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Oh wow! Im liking the direction this is going, but how about we move it over to my build thread? We can get into details and nitty gritty good stuff!!

Hmmmm - or maybe we should start a new thread on HPA & AA nozzle design?

Im good either way.

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I’ll answer this to get you started.

The ideal droplet size is between 20 -80 microns. Cycle timing depends on the volume of the root chamber, number of nozzles, and flow rate.

You want the ON time to be just barely enough to fill the chamber with the correct size droplets. You need enough nozzles so that the entire chamber is uniformly covered. Preferably no voids or overly wet areas, and the mist should not spray directly on the roots if possible. The ideal OFF time is just short of the time the mist starts to fade away - just a little less than the hang time. Again the goal is to provide the roots with an environment that is as stable, and uniform as possible, at the perfect ‘wetness’ level.

I should point out that I have not achieved that ideal yet. Im still in the wet/dry cycle stage, but getting better.

So far, the best timing I have come up with for my 45 gallon chamber was 0.4 seconds ON and 75 seconds OFF with three of the old Aeromist nozzles. That was putting out aprox 0.5 gallons per day total - I think. I need to review my notes.

I dont have a good cycle time for these new nozzles yet. I will have to develop that as the roots grow. I think it will have to be a somewhat higher ON/OFF ratio, because these nozzles have a lower flow rate, but that might be offset by the smaller droplet size. I’ll have to figure that out based on how the roots are growing.

Oh - the two main types of AA nozzels are siphon fed and pressure fed as far as water delivery. From what I have gathered, either will work fine. I would lean towards siphon fed just to reduce the need for one more pump and regulator. The feed air pressures I have seen are fairly low - 20-40psi.

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:+1: I’ve always been impressed with how well some of those events are staged, in particular, I’ve wondered how these things are planned from a safety perspective. Though, I’m certain you probably have some good, behind the scenes, stories to tell.

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@anon32470837,

So pretty much the same as spraying paint HVLP? Either a gravity feed or a pressure pot, except with a smaller median droplet.

This sounds a lot like a xf/vf atomization on a spray gun. I have a few high quality spray guns, but the finest nozzles I have for those would have their median droplet towards 250um, in the medium range.

I’ll give spraying folks a call later today. Already have a proper stationary compressor in the shop. One hole in the wall gets an airline to the grow space.

I guess need to deal with drip and find some solenoids for control now.

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Im not up to speed on how HVLP systems are built, but yes.

You want a nozzle that will work with a relatively low volume of air, at low pressures, with fine control of air pressure, and of course timing. Too much air flow can blast the roots.

There are lots of options for solenoids and timers. My advice it to try to keep all parts using the same type and size fittings where ever possible. Adapters can add a.bunch to the total cost.

You will want an oil filter on the air line, or use an oilless compressor.

Some comments and numbers from Atomizer for flow rates, timing etc. As far as I know, there would apply to HPA and AA. They assume good droplet size, coverage and good hang times.

I would recommend root chamber no less than 15"-16 deep for high pressure aero. As for mist timing,a lot depends on the mist quality (droplet size range), nozzle flowrate, coverage and level of control you have…
In an ideal system, you would set the misting duration based on flowrate and chamber volume. For early growth, the misting duration would provide 0.02ml -0.04ml per gallon of chamber volume. For later growth, 0.06ml per gallon.
The interval between mistings is adjusted to provide the target daily throughput, which will be somewhat dependant on environment variables (light,heat etc). As an example, a 26 gallon chamber with one 1gph nozzle would need a 0.5- 1 second misting duration in early growth and upto 1.5 seconds for later growth. The interval between mistings for early growth would be 35-70 seconds (dependant on the misting duration setting) with a target daily throughput of 1.3 litres. For later growth, the interval would be around 50 seconds with a target daily throughput of 2.65L. The name of the game is to inject mist little and often to maintain an optimal aeroponic environment.
Most aeroponic systems have flowrate, coverage and/or control limitations which provides a defined wet/dry cycle rather than a constant mist environment.
Choosing the correct nozzles involves matching the mist pattern to the chamber and/or planting layout. Nozzles come in a wide range of types, full cone, hollow cone, flat fan etc. To make things more interesting, there are various.cone angles and short and long throw. Consider which nozzle pattern/type provides full and even mist coverage with the fewest number of nozzles (as this affects the system flowrate). For example,.narrow cone long throw nozzles are best suited to long narrow chambers with rows of planting sites. The mist is directed horizontally into the space between the two rows, This will generate two walls of roots running the length of the chamber with an open corridor of space allowing mist distribution. Be aware that roots can and will thwart even the best laid plans as they can sense where the nozzles are located and will try to grow towards them., Roots can grow horizontally into open space ( defying gravity),they can climb UP a sheer chamber wall and even attach themselves to the slick underside of a chamber lid to get closer to a nozzle. Making the nozzle locations adjustable is a good idea as is having nozzles that are accessible from OUTSIDE the chamber for easier maintenance.

A starting point for the pause duration is not as easy, a stopwatch is useful for checking how long the mist hangs. After that youll have to judge if you have too little or too much pause time based on how wet the roots are. Adjustments may take an hour or so to become apparent, increasing the pause time allows the roots to use up excess standing droplets but you could find youve overshot it and theyre too dry after a couple of hours. Similar situation when decreasing the pause where youll see excess droplets forming on the roots.

Theres no wet/dry time with AA, the roots are suspended in constant mist. Finding the right mist density is the first hurdle, too much, too moist or too large a droplet size and everything is soaked. Too little or too small a droplet size gives too dry a mist the roots cant use. Pause length is set to let the mist gradually fade down to a light haze just before the next pulse. Use too long a cycle and the mist is completely gone (too dry), too short a cycle and excess droplets start building up on the roots (too wet). Youll need a fairly long pulse to fill a 1100L chamber

The target daily throughputs are based on full coverage of 5-80 mist which hangs for the entire pause duration and then some so the roots are never without mist. If you dont have it, the best approach is to make the pulse as short as practical to maximise the number of mistings and adjust the pause based on root wetness and structure. In a lot of cases you`ll find the target daily throughput numbers are reasonably close even though the pulse and pause timing will be different. If the ideal total nozzle flowrate for a chamber is 4.5LPH, and you need 3 x 4.5LPH to get the coverage, you are forced to use 3x the pause to achieve the same daily flowrate.

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Larry is correct – we doubled our harvest and more than halved our nutrient use with our first run. However to be fair the HPA run is lit by 4 QB-300’s vs the soil room that runs a shitload of older HPS fixtures (new bulbs every run). We are thinking of adding a few soil buckets to the HPA room this run so we can better compare the LED vs HPS.

His inability to share information is the entire reason I posted my grow log listing every part w/ links. It’s also the reason my grow log is not on RIU and is over here instead.

Hell yeah man – the more people experimenting and sharing details the better off everyone is. I’ve made plenty of mistakes, but I’d rather post them so someone else can learn from my failures instead of having them waste their time and money.

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A nozzle up-date. These nozzles are for sure different from the Aeromist nozzles. I cant decide if its better or worse. I for sure havent found a good timing setting yet.

The plant looks good up top and is growing, but it seems to be growing a little slowly to me. Its hard to judge that because Ive never grown this strain before.

This was it on the day I put it in the chamber. - 2 Nov

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This is it today - 5 days later. Its hardly any taller, but is spreading out.

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The roots are what have me the most concerned. They are staying very thin and not growing very fast - at least not compared to the previous unknown seedling. There is also no sign yet of any fuzzy hairs.

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The other seedling had started to explode with roots by this same time.

Ive been running slightly longer ON times with these nozzles because of the lower flow rate, but Im now thinking that they are still not long enough. 0.4 seconds was great with the old nozzles, so I thought 0.5 would be good, but it seems too dry. I bumped it up to 0.6 and that still didnt seem to do it, so Im now at 0.7. I need to give that at least several hours to see how the roots respond.

Im wondering if the smaller average droplet size is part of the ‘problem’ as well. A percentage of the droplets may be too small for the roots to use easily.

I may need to order some additional nozzles with the next size up orifice - havent decided yet.

The people I got these from - EchoLogic - seem like nice folks, and they had no problem shipping me out some new springs, but they are slooooow compared to the Aeromist guys. Its taking them more than a week to get me parts. Thats hard to take after getting spoiled by 2 day shipping from Amazon and 3 days from Aeromist :slight_smile:

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Not by any means HPA expert here, but they look like “looking for water” roots (more alongared than bushier).
Sometimes (in DWC) I get these roots when I have some nutrient imbalance (too high/low EC), as they are perhaps “searching” for food/better food source.

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Yeah, thats a possibility I guess, but I think I have everything fairly close as far as nutes. PH is staying in the 5.7-6.2 range, and EC is 0.6.

Not much change this morning after 6 hours at the longer timeing. They still look very thin. Im leaning towards the droplet size being too small - which would be inline with your thinking they are looking for water. Im going to swap the Aeromist 0.024 nozzles back in for a day and see what happens.

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