Aeroponics discussion thread for HPA/AAA and maybe another grow

[anon32470837]

Side note here on my current experiments - which are not working out as I hoped as far as fuzzy hairs.

For quite some time I have had the feeling like things might work better if I had a lower VMD = smaller droplets. Several things lead me in that direction.

1. Ive seen fog-ponics grows using ultra sonic misters that actually produced some nice fuzzy hairs - for a while. Those misters have other serious issues that I dont like, but they seem able to make fuzzies even though the droplet size is sub 5 micron or way too small according to atom
   .
2. In looking at some of atomizers videos, his hang times were a lot longer than I was getting with the delavans. His OFF times between roughly .5 second ON cycles, were in the 90 second range, and there was still a good deal of mist in the chamber. That indicates there were droplets hanging around that were in the 10 micron range and smaller.

He has said several times that you want droplets between 5 and 80 microns, so that fits. The problem for us is that there is no way for us to know for sure what droplet sizes we are getting. All we can do is measure the hang time and calculate what the SMALLEST droplets that are left in the chamber based on that hang time.

These two charts tells how fast droplets fall in still air.

I also was going off of a research paper @heathen found that covered some smaller flow rate Delavan nozzles. The key take away from it for me was that the droplet size varies based on the Air to Liquid mass ratio or ALR. Its not the relative pressures, its the mass of air vrs the mass of water leaving the nozzles.

EffectofAtomizingAirFlowonSprayAtomizationofanInternalMixTwin-fluidAtomizer_Chong.pdf (501.4 KB)

Anyway, all that led me to decide to experiment with higher ALR’s to try to get smaller droplets on average - lower VMD.

So far, its not working very well at all. I started with the Spraying Systems SU2 siphon feed nozzles and got zero fuzzies. I think at least part of the problem is they have too long a throw distance for my small chamber - even at the lowest air pressures I tried.

Now Im back to the tried and proven delavans. Ive been running them at much higher pressures and much higher siphon heights than I did in the past.

Before I was running them at a max 0.5" to 1" siphon height and air pressures from 7 to maybe 10 PSI worked well. Now Ive been up to 4" siphon height and 30 PSI. Thats giving me much longer hang times - up to 3 minutes.

Ive been playing with the new settings for over a month now on two different sets of seeds with zero fuzzy hairs.

BUT - I just last week discovered that my nozzles have become partially clogged in the air passages. This could be due to corrosion of the brass where it is close to the stainless or it could be debris that has become stuck in there. The water passages on these nozzles are very large, and would be impossible to clog easily. Plus I can see right through the water path. The air passages on the other hand are much tighter clearances.

The net result is that the three nozzles I am using have very different water and air flow rates.

So, Im now running the nozzles back at the original settings that produced fuzzy hairs and I have ordered three new nozzles. They will be hear next week some time - just in time for me to start some new babies in the chamber of death…

Which reminds me - one other possibility for the lack of fuzzies is the seeds Ive been using. Ive been using seeds that have not worked out well for me in the past - lots of issues, mutants, slow growth etc. I doubt this is all of the problem though. I did get fuzzies with these seeds on my last grow.

Now for more waiting…

[anon32470837]

@JoeCrowe

The fuzzy roots in question when they are exposed to certain pressure from the water, don’t even remember the number, they definitely transform into smooth, your microscope is not lying to you

@anon32470837

Where did you get the info on the water pressure causing changes in the hairs? id like to follow up on that as it may have a bearing on my current experiments.

I almost forgot about this. The reason Im interested in reading more on water pressure vrs fuzzy hairs is that all of my recent failed experimenting has involved higher air pressures and/or narrower cone angles. The net result is water leaving the nozzles with more speed and hitting with more force.

The Spraying system nozzles have a cone angle of around 18 deg and a throw distance of up to 18 feet. the delavans have a cone angle from 30 - 65 deg depending on pressures and a much shorter throw distance. The cone angle goes down as pressure goes up and the throw distance increases with air pressure.

Wider cone angles, matched with lower air pressures means less force on impact.

As a contrast, the HPA nozzles I used had a cone angle more like 80 deg and very short throw distances even at 80-100 PSI.

So, Im now wondering if this might be a factor in my lack of fuzzy roots.

[JoeCrowe]

unfortunately that information was from the original overgrow. On the other hand all the studies on root hairs just say they form in “moist air” I was using 90% RH for that. Gotta be more specific info around though. I’ll read some shit. Interesting side note, they claim the root hairs “absorb” things. Except… you can see those smooth roots from the DWC have no hairs, so the absorption must be through something else like the root epidermis cells. I think the epidermis forms the root hair, so it makes sense.

[anon32470837]

It was my understanding the hairs were not really that different. It was mainly a matter of more root surface area, plus more efficiency, so effectively having more roots when you have hairs. However, that is just anecdotal comments from other root nerds. Ive never seen any studies on root hairs. Gonna have to look

[anon32470837]

LOL Google is amazing some times. I googled “root hairs” and got this as one result.

How plant roots grow hair

Smoke molecules cause root hairs to grow

To check their hypothesis, the team of researchers exposed young arabidopsis plants to the karrikin molecules as they occur in smoke. This indeed significantly increased the growth of root hairs.

Im not sure how this helps anything we do but it sure is interesting! Maybe I need to buy a carton of Marlboro cigarets and see how it goes…

There are tons of results for “root hairs” and Ive only begun to search, but this one caught my eye. Lots of very interesting information about roots and light. It looks to me like light by itself isnt really all that harmful to roots. In fact, several plants roots seem to develop MORE hairs in the presence of light!

Development of root hairs.pdf (1.8 MB)

Still reading and looking but nothing - so far - about pressure being a factor.

[GnomeyByNature]

Damn I have some reading and catching up to do, that was fast

[Sincy]

I love some good root porn and info.

[JoeCrowe]

I must have read 100 different publications. They all refer to the “root hair” as absorbing water and minerals through passive and active transport. On the other hand, now I am a plant physiology expert lol! The weird part is the smooth roots are an adaptation for aquatic plants, where the roots don’t need to support the plant and there is water everywhere.
https://plantcellbiology.masters.grkraj.org/html/Plant_Cellular_Physiology2-Absorption_Of_Water.htm
this was the most detailed and outta sight article I read. LOL unfortunately it doesn’t contain the answers we are looking for. sigh I guess it’s time to start gathering observations.

[JoeCrowe]

I can’t help myself but there was another article I had read online that was…so good!
https://www.nature.com/scitable/knowledge/library/water-uptake-and-transport-in-vascular-plants-103016037/
I read this one a couple of times, lovin’ it!
combine that article with the first one and you’ll be 7th level root master.

[JoeCrowe]

ok for what it’s worth, they say the roots exude ethylene to promote root hair formation. When there is some actual water that runs over the root it washes away the surface ethylene, resulting in the inhibited root hair growth. I suppose that means there can’t be enough moisture around to cause a drip to form or else the roots will be smooth.

[anon32470837]

[quote=“JoeCrowe, post:30, topic:36453”]ok for what it’s worth, they say the roots exude ethylene to promote root hair formation. When there is some actual water that runs over the root it washes away the surface ethylene, resulting in the inhibited root hair growth.
I suppose that means there can’t be enough moisture around to cause a drip to form or else the roots will be smooth.
[/quote]

That pretty well sums up the balancing act when you grow with HPA or AA.

That is not easy to do sometimes. First - you need more than just a humid grow space. There has to be enough actual droplets of water collecting on the root hairs to keep them alive. If you just have humid air, they “air prune”.

See in these pics how parts of the root mass are nice and white and fuzzy, but other places the roots are shriveled and browning?

This happens when you have uneven mist distribution in the chamber. Some places get the correct amount and size of droplets, while other places get too little - or too much. This is one of the things Im trying to make better with this latest set of changes.

Up until today, its looking like I am delivering too much mist to get any hairs - or too much pressure?

Yesterday, I lowered the air pressure down to 7 PSI and reduced the siphon height back to 1", and tonight I finally see some fuzzy hairs! Not much but its a lot better than zero

[GnomeyByNature]

@anon32470837

LOL Google is amazing some times. I googled “root hairs” and got this as one result.

How plant roots grow hair | ScienceDaily

Smoke molecules cause root hairs to grow

To check their hypothesis, the team of researchers exposed young arabidopsis plants to the karrikin molecules as they occur in smoke. This indeed significantly increased the growth of root hairs.

Im not sure how this helps anything we do but it sure is interesting! Maybe I need to buy a carton of Marlboro cigarets and see how it goes…

There are tons of results for “root hairs” and Ive only begun to search, but this one caught my eye. Lots of very interesting information about roots and light. It looks to me like light by itself isnt really all that harmful to roots. In fact, several plants roots seem to develop MORE hairs in the presence of light!

Development of root hairs.pdf (1.8 MB)

Still reading and looking but nothing - so far - about pressure being a factor.

I haven’t read that article, but what do you think would happen if you put a UV light in your chamber? I would imagine it would kill any algae but also probably all bacteria good and bad… they also make some UV lights that produce ozone and I’m not sure if that would be good or bad and if it’s bad, you can get some that don’t make ozone.

[GnomeyByNature]

@anon32470837

@JoeCrowe

The fuzzy roots in question when they are exposed to certain pressure from the water, don’t even remember the number, they definitely transform into smooth, your microscope is not lying to you

@anon32470837

Where did you get the info on the water pressure causing changes in the hairs? id like to follow up on that as it may have a bearing on my current experiments.

I almost forgot about this. The reason Im interested in reading more on water pressure vrs fuzzy hairs is that all of my recent failed experimenting has involved higher air pressures and/or narrower cone angles. The net result is water leaving the nozzles with more speed and hitting with more force.

The Spraying system nozzles have a cone angle of around 18 deg and a throw distance of up to 18 feet. the delavans have a cone angle from 30 - 65 deg depending on pressures and a much shorter throw distance. The cone angle goes down as pressure goes up and the throw distance increases with air pressure.

Wider cone angles, matched with lower air pressures means less force on impact.

As a contrast, the HPA nozzles I used had a cone angle more like 80 deg and very short throw distances even at 80-100 PSI.

So, Im now wondering if this might be a factor in my lack of fuzzy roots.

Maybe, as you said, short throw is key because maybe what we should be after is actually the turbulent part of the spray?

[VandalBee]

@anon32470837

If you were not getting any root rot, then your water temps must not have been out of line. Do you run sterile rez or beneficial bacteria or anything like that?

Sterile rez.

@anon32470837

Have you grown any plants yet with the HPA nozzles or are you still in the testing stages? One comment on your setup is maybe dont get the plants too close to the sides. In my grows, Ive found that when the roots are too close to the sides of the chamber, the part nearest the sides doesnt get sufficient mist and tends to air prune and/or stray smooth unless you are over misting the rest of the roots.

Still in experiment phase. Thx for the advise - much appreciated.
Below might be a way better solution:

@anon32470837

Interesting idea using your air compressor to drive a pressurized rez rather than one of those aquatec pumps. Have you tried this yet? One problem I ran into was when I had air trapped in my accumulator tank. I was running 100-120 PSI in the tank and that air caused major problems. The main one was that that hi pressure air increased the dissolved C02 in the water. That did two things. It drove the PH down drastically, and it caused fizzing in the water when the pressure dropped again - just like in soda when you pop the top. The PH issue was a real pain. Running at lower pressures, you may not have that issue, but you might want to check the PH as the water leaves the nozzles to see if its still within range.

That is a very good point. I haven’t thought about the co2 dissolve issue. Thx for saving me time, energy and money. Taking a second look, its not going to work due to the ph issue you pointed out.

@anon32470837, looking at the nozzle you use, I feel it might be a bit of an overkill for the chamber you have, meaning it cant syphon from up to 2-3 meters, which imo is alot. That could be one of the reasons you get these results. I’m thinking a lower number from the parts list could be a better match.
In addition the cfm of the solenoid is curtail as well.

Take a look at
https://monstergardens.com/the-microfog-low-pressure-carbon-fiber-atomizer-1-4-inlet-output.html.html

According to the spec:

Nozzle produces 0-30 Micron Fog at 35 PSI. It can produce a 30-100 Micron Mist at 25 PSI and can produce a 200+ Micron Spray at 18 PSI.

I ran couple of tests with it with different psi levels - from 30 (which I think its the 50 micron size) down to 20. Looks like it performs best at 28. But that is based on a 18" syphon line - too long imo and a very bad solenoid.

nozzle test 1 30psi

nozzle test 2

nozzle test 3

nozzle test 4

last one is with a cap without the ultrasonic tip.
In one of the videos where I dropped it to 20 psi It did not mist at all due to the syphon line going out of the water rez
Imo there is a potential if the nozzle line is 2-3 times shorter, its gravity fed and there is a proper solenoid that has good cfm flow. I would use 3/8 tubing and fittings, more precise regulator - 0-60psi.
Amazon.com - but the 3/8 version if available. If not the 1/4 has to be taken apart and drilled with 3/16 to make the air line whole bigger to allow better air flow - same for the push fittings.

[anon32470837]

Sorry folks. Im under the weather, so just a fast note. I lost the fuzzy hairs!

@anon32470837

Yesterday, I lowered the air pressure down to 7 PSI and reduced the siphon height back to 1", and tonight I finally see some fuzzy hairs! Not much but its a lot better than zero

I made a very small change in settings and when I checked again, they were gone. Nothing I have done since has helped.

Im down to thinking this could be due to my alternate timing sequence. I’ll explain my thinking more when Im feeling better. I just re-wired the solenoids so they are all back on the same timer and firing at the same time. We will see…

[Howard.Crane]

Hope you feel better soon! Best wishes!

[JoeCrowe]

I’ve got a few more observations to make about the hairy roots.

you can see very minute drops of water clinging to the hairs on those roots.Just zoom in a bit. It seems to me, if the drops that form are too large, it will make an actual drop that encompasses the hair, and snuffs it out. Those tiny water drops and hairy roots form in DWC under certain conditions…

1. above the water
2. tiny tiny drops, not enough to form a real drop that encompasses a hair.
3. crazy thin layers of adhesive water everywhere nearby.
   In my world, I just want to pump some buds, so those roots, will be flooded out and never be hairy again. Except, if I keep a 15cm air gap, the hairy roots will stay. You ever tried running the sprayers underneath the roots spraying sideways? Just whiffing out an idea, you can tell me if it’s insane
   I would suspect the timing on the water spraying is important because you want to generate more tiny drops before the last batch evaporates but not spray too often so the tiny drops build up into a real drop that does hair damage.

[VandalBee]

Great calculator for cfm to cv ratio. It lets calculate the what cv rating you need your solenoid to have based on the inlet/out pressure and nozzle cfm consumption.

Cv Calculator | Flow Rate and Valve Calculator

[anon32470837]

Im mostly back, but have a ton of stuff Im trying to catch up on. Lots of stuff to comment on from above, so I will do a short bit now…

@GnomeyByNature

I haven’t read that article, but what do you think would happen if you put a UV light in your chamber? I would imagine it would kill any algae but also probably all bacteria good and bad… they also make some UV lights that produce ozone and I’m not sure if that would be good or bad and if it’s bad, you can get some that don’t make ozone.

Interesting idea, but I would be careful. I used hi end UV sterilizers back in the day in my saltwater aquarium days. They worked well. Fast forward to trying cheap imports in my rez, and it was a total waste of time. Actually worse than a waste of time because algae actually grew ON the f’ing lights! To be fair, these were cheap UV lights.

As far as in the root chamber, I suspect you would do more damage than good, but if you have a nasty root rot situation, it might be worth a try. I suspect you would just give them sunburn though I dont know what ozone would do but roots dont normally have to tolerate that, so it might be bad or good?

@GnomeyByNature

Maybe, as you said, short throw is key because maybe what we should be after is actually the turbulent part of the spray?

I suspect thats true in many cases, but it probably has more to do with flow rate and how wet the roots get - like @JoeCrowe has mentioned too much water washes off the coatings, and in my experience large drops inhibit hairs.

On the other hand, I have had good results while spraying pretty directly with the Delavan nozzles at short distances - but - at low pressures.

I suspect velocity and flow rate in combination are the key things.

@VandalBee

Below might be a way better solution:

That might work better in some ways, especially with long narrow throw nozzles, but you need to keep an eye out for uneven coverage. You would have to try it to be sure. Even coverage has been my biggest challenge.

@VandalBee

looking at the nozzle you use, I feel it might be a bit of an overkill for the chamber you have, meaning it cant syphon from up to 2-3 meters, which imo is alot. That could be one of the reasons you get these results. I’m thinking a lower number from the parts list could be a better match.
In addition the cfm of the solenoid is curtail as well.

Im not sure what you are meaning here. The Delavans Im using have a max siphon height of 1 meter, as do all of the Spraying Systems nozzles. The smaller Delavans only go up to about 1.2 meters max.

Even so, i dont see what siphon height has to do with it? Its flow rate and droplets sizes (VMD, SMD etc) that are the important factors.

The air solenoid CFM ratings could be an issue, but only as far as air flow. That is easily compensated by increasing the inlet pressure. Or am I missing something else?

@VandalBee

Take a look at
https://monstergardens.com/the-microfog-low-pressure-carbon-fiber-atomizer-1-4-inlet-output.html.html

According to the spec:

I have a long list of issues with those guys that I cant get into now, but most of them boil down to many of the things they say dont add up or dont agree with what reputable companies like Spraying Systems say and the research papers I have read. For one thing, that “ultrasonic” tip is just an impingement tip. There is nothing ultrasonic about it and ultrasonics have nothing to do with the way it breaks up the spray. Plus, droplet distributions dont work the way they show in their “specs”. There are at least a dozen other things on the website that are similar. To me they just ooze stoner-science

That said - the nozzles may work fine. You would need to try them to be sure.

I have to run, but looking at your videos of the spray, they may work just fine. You should put a lid on yoiur containers, and seal them up well so you can get a true idea of what the mist looks like, and see what the hang time looks like.

You should also measure the actual liquid flow rates to see how well they match up to the specs. Just weigh your water tank before and after doing a series of 50-100 cycles. One other tip - dont run the water supply in from the top, and try NOT to have horizontal tubing runs near the nozzle. The water will drain out between cycles causing the flow rate to look higher than it really is.

You can see some of this problem by watching the floor of your chamber and seeing the large drops splattering. Also, if you watch the droplets pattern, you can see large droplets falling out of the spray close to the nozzle - proof that their “specs” are at least partly marketing BS . All nozzles produce a wide range of droplet sizes.

crap - sorry to bash those nozzles and run… I am more concerned by the company/people/marketing BS than the nozzles…only way to know about the nozzles is to try them.

[VandalBee]

I will test it out for sure.

As for the Delavan, there are a lot of Chinese versions that are stainless steel - I got in contact with the one of the sellers to get the version match - link, link