Aeroponics discussion thread for HPA/AAA and maybe another grow

[anon32470837]

I would not trust anything they say.

The “specs” they list have nothing to do with any Delavan nozzles, plus they dont even agree with themselves.

The working pressure range is 0-10/kg/cm2, different flow capacity needs different filter screen

    Flow capacity range is 1.5-1.7 L/h, needs a 45um oil filter screen

    Flow capacity range is 1.89-3.78 L/h, needs a 75um oil filter screen

   Flow capacity range is 4.76-5.10 L/h, needs a 125um oil filter screen

   Flow capacity range is 5.68-41.64 L/h, needs a 140um oil filter screen

   Flow capacity over 45.42L/h, no need for oil filter screen

Working pressure is 3 bar:

0.5mm diameter, the liquid water flow is 4 L/H;

0.8mm diameter, the liquid water flow is 6 L/H;

1.0mm diameter, the liquid water flow is 8 L/H;

1.5mm diameter, the liquid water flow is 11L/H;

2.0mm diameter, the liquid water flow is 14L/H;

2.5mm diameter, the liquid water flow is 17L/H;

3.0mm diameter, the liquid water flow is 20L/H;

3.5mm diameter, the liquid water flow is 23L/H;

4.0mm diameter, the liquid water flow is 26L/H;

The siphon height is 30cm, and the spray angle is 15-45 degree.

Note at the top they list working pressure as 0-10/kg/cm^2? Thats equal to 9.8 BAR, but lower down they say the working pressure is 3 BAR. The max pressure for any Delavan nozzle is 2.8 BAR.

The lowest flow rate they show is 1.5 LPH up to 45 LPH. Delavans go from 0.4 LPH up to a max of 9.8 LPH and they only go that hi with a gravity head of 0.6 meters. The max siphon flow rate is about 7 LPH.

They also number them in mm. I can only assume that is the liquid orifice diameter. They show a max of 4MM. Delavan doesnt make anything even close to 4mm. My nozzles look to have maybe a 1mm orifice, and they are near the upper end size wise.

These guys are just making stuff up as far as specs. Im surprised they didnt even bother to copy the Delavan spec sheet.

Also, look closely at the pics. You can see that the liquid orifices are recessed unevenly from one nozzle to the next - some are more and some less. Thats a critical distance. Too far in and no siphon action. Too far out and poor atomization. Sloppy QC.

[anon32470837]

@VandalBee

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.

As I said above, I would run those tests with the lid on, and use a proper timer. You will need a small hole in the top and side of the chamber. In the top hole, shine a light in. I like using a cat laser toy. Then use you phone camera to take a video so you can see what the hang time is like. Let the timer run for several cycles so the chamber gets completely filled with mist. Then turn OFF the timer and start the camera recording at the same time.

Here are a couple of mine from earlier grows.

laserhangtime

I just realized I need to upload some new ones.

Anyway, you can see how the mist begins to thin out over time. At some point it will begin to disappear at the top and work its way down. When you call it as far as how long your hang time is is very subjective. I call it when the mist starts to disappear in significant patches. In that video, I would call that somewhere around 90 seconds. In my chamber, that means my smallest droplets were somewhere under 10 microns. Note that there is no way for us to tell what the max droplet sizes are or the distribution of droplet sizes - VMD (Volume Median Distribution).

If you dont have a lid sealed on the chamber, the smallest droplets will evaporate or disperse way too fast. Plus, its really hard to judge mist quality in open air. You just cant see it all.

@JoeCrowe

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.

Dang Joe! You are getting to be a master of this AA stuff.
If you take a close look at my fuzzy root pics in the first post, you can see very tiny droplets. You can also see a few larger droplets here and there, but not many and typically only on the growth tips where they hang down.

@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.
https://www.swagelok.com/en/toolbox/cv-calculator#

Thats a cool calculator! Unfortunately, I have never measured the outlet pressures and have no way to accurately measure my air flow rate, so it doesnt do me much good. The nerd in me loves it though

Ok, I think Im all caught up on replies

In other news - still no fuzzy hairs!!! Im starting to get annoyed. I just decided to go back to what was working last time I had a similar setup and see if THAT works. Grumble grumble fuss and fumble - or something like that

[GnomeyByNature]

Quick question, how do you measure siphon height? Would it be from bottom of bucket or water level? Would the size of the bucket and amount of water (weight) effect it?

PS I friend to test yesterday, had my chamber all setup (or so I thought) and laser inside, but as I went to seal up all the holes with net cups /foam, the 2” net cups didn’t fit in my 2” 45 elbow pvs cause I got net cups with wide lips like a moron lol

I hope to have some video up this week tho…

How important do you think it will be for testing purposes to have a drain plumbed in?

I assume it’s probably a good idea anyway else it might pop out those net cups hehe

[anon32470837]

@GnomeyByNature

Quick question, how do you measure siphon height? Would it be from bottom of bucket or water level? Would the size of the bucket and amount of water (weight) effect it?

Its measured from the top of the water in the siphon tank to the nozzle opening or tip. The height of the water inside the siphon tank makes no difference.

However, see my comment above about how you route the water lines to the nozzle. When the nozzle fires, it will suck water from the tank and fill up any empty portions of the tubing in between. Look at the drawing below.

On the left the nozzle is shooting up and on the right the nozzle is shooting down. Technically both nozzles have the same siphon height.

However, the nozzle on the right will use significantly more water on each cycle. Thats because the water in tubing connecting the right hand nozzle will drain out in between cycles. See the parts where I added the red on the right.

The right hand nozzle will have a somewhat (probably minor) lower flow rate while its on because the water has longer tubing to go through and two extra elbows.

Those differences in the ON flow rate wont cancel out the wasted water though.

For example, in my setup each nozzle is putting out around 0.6 ml per on cycle at my current timing. My setup is like the left side in that drawing. I have about 18" total of 1/4" tubing connecting the siphon tank to the nozzle.

If I had the nozzles firing down, like the right side, I might have say 12" total of tubing in the red zone. That works out to a total volume of 2.5 ml of water that could drain out in drips while the nozzle is off. That doesnt even count how much water the nozzle itself holds. That means I would be wasting more than 4 times as much water as I was spraying on each cycle.

If you used 3/8" tubing, the waste would be a lot more.

So, you need to think carefully about how you run the tubing when firing down or sideways with siphon fed nozzles. You want the least amount of horizontal run above the nozzle as possible, and the shortest vertical length down to the nozzle. Minimize that red zone.

@GnomeyByNature

How important do you think it will be for testing purposes to have a drain plumbed in?

I assume it’s probably a good idea anyway else it might pop out those net cups hehe

Yeah, you need to allow for the air your blowing in a way to escape - but - you dont want drafts back and forth. You might try putting a piece of cloth over an opening. Something that will let air out easily, but not tooo easily so it blocks any drafts. You also want to keep any light out so cover it some way to block light.

My root chamber is made from regular fabric growing pots. The fabric is loosly woven. If you put one over your head, you can easily see light through it. It “breaths” extremely well, but I have to keep light from getting into the chamber area. I have is surrounded by 1" foam panels. Those panels keep light out and keep heat in - I have a small heater inside the foam box and outside the fabric chamber. I need the heater because my chamber stays 7 to 10 deg F colder than room temp due to evaporative cooling as the mist wets the fabric.

[GnomeyByNature]

@anon32470837

Its measured from the top of the water in the siphon tank to the nozzle opening or tip. The height of the water inside the siphon tank makes no difference.

Hmm, I’m a lil confused by this, it’s sounds contradictory to itself? If the height is determined by measuring the top of the water to the tip like your diagram, then wouldn’t the height then make a difference, ie once you use some of it up and it gets lowers maybe the flow changes?

I’m just talking shop and for testing purposes…

I’m actually going the have a circulation pump bring the nutrients pretty close to the nozzle where I will have a tee that will feed the nozzle…

So I feel like there won’t really be any pressure there and it will be more like a siphon… do you think for testing purposes (when I bench test before pump setup), a comparable siphon height would be zero? The distance in height between tee and nozzle tip?

I might possibly try to get the tee right next to the solenoid…

And I’ll be shooting up, so I should be similar to your left diagram

[anon32470837]

By the way, the reason you need to think about the plumbing and how much waste you might have on each cycle has to do with some of atomizers math on “filling the chamber with mist” and daily flow rates or through put.

Here is a quote from him:

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.

As far as filling the chamber, when you do the math, he recommends that each ON cycle deliver .02 to .04ml per gallon of root chamber during early growth, and up to .06 ml per gallon of root chamber in late growth. Filling the chamber is determined solely by the ON time.

BUT - drips and dribbles dont count because they are not micron sized droplets that will hit the roots!

So for my 55 gallon root chamber that works out as follows:

55 x .02 = 1.1 ml total liquid delivered per ON cycle minimum in early growth, and up to as much as 55 x .06 = 3.3ml per ON cycle in late growth.

My nozzles each have a flow rate of about 3.8 liters/hr at the current 2" siphon height and 7 PSI of air. So right now Im running 2 nozzles that each deliver aprox 0.8 ml per 0.8 second ON cycle for a total of 1.6 ml/gallon delivered to my 55 gallon chamber. That works out to about 0.03 ml per gallon per ON cycle. Im on the low end at the moment with my current .8 seconds of On time.

If I follow his numbers for later growth, and end up at the max rate, I will need to increase my ON time to around 1.6 seconds for each On cycle - assuming I keep the same pressure and siphon height. That would put me at aprox .06 ml/gallon per On cycle. Thats his max recommended number for filling the chamber.

However - this is assuming you are delivering mist with droplets that fall within that 5 micron to 80 micron range - AND - you have good mist density.

My current settings and flow rate are giving me what I think is a mist density on the thin side, but the roots are not drying out and look great - other than no fuzzy hairs

His second recommendation for daily through put or total liters per day flow rate is determined by the ON time plus the OFF time. Once you have an ON time set to fill the chamber, you adjust the daily through put by changing the OFF time. Longer OFF time lowers the daily through put and shorter OFF time increases the daily through put.

He recommends .05 liters/day/gallon of root chamber early and up to 0.1 litters/day/gallon later on.

Im currently running 0.8 sec ON x 70 seconds OFF which works out to .037 LPD/gallon. Thats well below his recommended minimum of .05 LPD/gallon. Thats because my roots are staying too wet even at this low flow rate.

Im still trying to solve this issue. My mist isnt dense enough, and my LPD/gal is too low (I think) yet my roots are staying too wet.

My current thinking is that this is due to changes in the tubing Im using for the air lines. Previously I was using 1/4" tubing everywhere, but I upgraded to 3/8" tubing and solenoids after my last grow ended. Im thinking that the increased air flow has caused an increase in pressure at the nozzle. So if Im running at the same 7 PSI at the regulator, the nozzle will have a higher air pressure than before and that means higher velocity of droplets. That inturn means more side splatter hitting the roots. It also means finer atomization - which I can see in longer hang times. I like the longer hang times, but I dont like the side splatter.

I think.

Only time will tell if my recent lowering of the pressure to 5 PSI will do the trick.

Sometimes I hate time…

[anon32470837]

@GnomeyByNature

Hmm, I’m a lil confused by this, it’s sounds contradictory to itself? If the height is determined by measuring the top of the water to the tip like your diagram, then wouldn’t the height then make a difference, ie once you use some of it up and it gets lowers maybe the flow changes?

You need some way to keep the level in the siphon tank constant. You’re right, if the water level drops, that changes the siphon height.

My rez is up on my work bench with tubing and filters running down to the siphon tank - which is inside the foam box and right outside the fabric root chamber. The siphon tank is only about 2 quarts in size, and has a float valve (about $12 at Amazon) that keeps the water level where I set it. I can adjust the float valve, or raise and lower the siphon tank to make changes in the siphon height or I can raise and lower the nozzles to some degree if I want.

The siphon tank has to sit so that the water level is always below the nozzles of course.

@GnomeyByNature

I’m actually going the have a circulation pump bring the nutrients pretty close to the nozzle where I will have a tee that will feed the nozzle…

So I feel like there won’t really be any pressure there and it will be more like a siphon… do you think for testing purposes (when I bench test before pump setup), a comparable siphon height would be zero? The distance in height between tee and nozzle tip?

No, there will be positive pressure. If there wasnt, no water would flow. That will drastically change your flow rates AND the atomization or droplet sizes.

Droplet size range is determined by the ratio of air mass to water mass at the nozzle. If you increase the amount of water, you also increase the droplet size range. Less water = smaller droplets. More air also = smaller droplets.
Im confused - why the pump?

@GnomeyByNature

might possibly try to get the tee right next to the solenoid…

What solenoid? For siphon setups you dont need or want a solenoid.

Maybe you should make a drawing of what you are planning. Im not getting it so far

[anon32470837]

Take a look at this part of the Delavan flow chart for some of the nozzles. I clipped it from the delavan PDF.
Delavan-SN.pdf (510.2 KB)

It shows the changes in flow rate for different air pressures and siphon heights (negative water pressure) and gravity head height (very small positive water pressure)…

[GnomeyByNature]

Here’s a quick and dirty kids drawing… not sure about the solenoid or not… was originally going to have tee closer to circ pump and have shut off valve on return side to create some positive pressure if I wanted it albeit even if it would be just minimal…

I think maybe the solenoid might be useful for runoff?

I don’t know if this nozzle is only siphon or can also or only do gravity/pressure as the description states.

[anon32470837]

If you are going to use a siphon type nozzle, put the circulating pump inside the rez, then ditch the T and use the solenoid on the air side only. Other wise, you will have a flow rate off the charts on the hi side.

You will need a separate, small siphon tank. I seem to remember you were going to grow outside - vertical tank type grow?

If so, you will need to elevate the tank to some degree to allow the water level in the siphon tank to be below, or even with the nozzle tip.

Something like this:

I didnt show the air side and its solenoid. the red thing is the float valve. This is the one Im using. I’ve had it in use for almost 2 years with no issues.

Amazon.com: Malida Water Filter Float Ball Valve,or Fish Aquarium Uses 1/4 Inch...

It will fit in a small container. Im using an empty Carnation coffee creamer plastic jug. Its maybe 6" in diameter and I cut it down to about 7" tall. I use hot glue to attach 1/4" tubing to it. Just drill a 1/4" hole, stick the tubing in and hot glue all around it - inside and out. I sand the tubing and container where the hot glue will be to get a better bond. No leaks yet

Speaking of siphon heights, if you are going to use one of these Delavan nozzles, Id recommend you get as close to zero siphon height as you can. I just got reminded of the reason I was using as close to zero as I could get - the nozzles spit a good bit when the cycle starts if the siphon height is much over 1". If its close to zero, no spitting.

On the circulating pump and the rez - I have an aquarium pump inside the rez, but it only runs 1 minute every 40 minutes and I may slow that down to once an hour. You dont need to aerate the rez water. That will happen just fine when it gets atomized. So the only reason to circulate is to keep any nutes stirred up.

I dont even really need to do that since I changed from Mega Crop over to Jacks at ridiculously low EC levels. I just went from 300PPM down to 200PPM because the leaves were too dark. My water is about 100PPM or less. My rez always looks like perfectly clear water. There is nothing to keep stirred up.

The only real reason to have a circulating pump is to help with mixing the nutes when you re-fill the rez and when adjusting PH and adding chlorine for the sterile rez.

[GnomeyByNature]

I know about float valves, I put one in a keurig to auto fill it lol

My res is not going to be that big actually and it will be in a mini fridge where it is auto dosed/ph’d and topped from an RO line… I like the external pumps for various reasons… the chamber will be elevated a lil above res as well even just for drainage purposes… my circ pump will be a pretty low flow pump, it’s tiny and further I lower the voltage from 12v to 6v… this setup is intended to just bring the water right to near the nozzle… I don’t think it’s going to create much if any positive pressure because it is going from one line essentially into two lines (nozzle and return)… if it’s anything I would think it would be like 1psi at most (it’s not a booster pump)… I also have the nozzle flow adjustment which limits the fluid flow as well if it’s too much so I think that should be fine…

And yes, quasi outdoors in an open plastic greenhouse in a vertical drum chamber with the reflective bubble on it

[anon32470837]

Get that thing put together and shoot some mist videos

I forget - which nozzle are you going to use?

[GnomeyByNature]

Right now it’s going to be the amazon Chinese SS knockoff listing that says it’s cone 80 degrees… Not sure if it even says if it’s full cone or hollow… hoping to get something up in the next couple days… my net cups that I’m hoping will fit are coming today.

[anon32470837]

@GnomeyByNature

I don’t know if this nozzle is only siphon or can also or only do gravity/pressure as the description states

As far as I know, the siphon only nozzles can only handle a very small amount of pressure, and the pressure fed nozzles cant do siphon at all.

There is no way to tell about your nozzle until you test it, but I tried three different ones like yours that claimed to be both pressure and siphon. None of them would siphon. They wouldnt even work with up to about 3 feet of gravity head.

As far as I know, all the siphon type SS nozzles have a max gravity head of 18". That works out to about 0.7 PSI max. The lowest pressure feed water pressure Ive seen in the charts is 3PSI, so there is a fair difference between the two feed types, and no over lap.

You will just have to try it out and see what happens.

[GnomeyByNature]

Can you describe what you mean by “work”?

Are you talking fuzzies “work” or absolute malifunction, like too much pressure to a siphon nozzle and water would just start dripping out or the spray would be very far from intended sort of thing?

[anon32470837]

In the case of a pressure feed nozzle, when I say it wont work as a siphon feed, I mean it wont suck up any water. At all.

The ones like yours that I bought refused to siphon at all. Zero water flow. They actually blew air back into the water tank even at the lowest air pressures.

Siphon feed nozzles are a different story. They are designed to work with very small positive pressures - but - every one I have see is rated for well under 1 PSI max. Or roughly 0.6 meters/18 inches maybe of positive gravity feed.

Now, I am sure you could still pressure feed a siphon nozzle and water would spray out. The problem is the droplet size would be much larger than what they are designed to produce.

Remember before when I mentioned the air to water mass ratio? That ratio is what determines the size of the droplets. Higher air to water = smaller droplets. Lower air to water = bigger droplets. Its called the ALR or Air to Liquid mass Ratio. Its the ratio of the mass of air flowing through the nozzle vrs the mass of water flowing through it.

For example, lets take my nozzles because I have run the numbers already.

With a siphon height of 1" the ALR looks like this at different air pressures. The M^3/min is the air flow rate and the LPH is liters per hour of liquid flow. I did the math to convert those to mass ratios to get the ALR. Bigger ALR means smaller droplets on average or a lower VMD.

|

That above is at 1" siphon height. At 18" gravity feed height the number change like this:

Remember, that is only 0.6 PSI. You can see the ALR went down a lot which means much larger droplets. At higher pressures, the ALR will get even worse and at some point not too far above that 0.6 PSI all atomization will stop and you will just get splatter with all large drops. It will be no better than LPA.

The same thing applies to pressure feed nozzles when you change the ratio of air to water, but those nozzles are designed internally to handle much higher water pressures.

I dont remember if I posted this already, but here is a study of a smaller Delavan nozzle that goes into the theory of ALR and shows exactly how air to water pressure effects droplet sizes for this nozzle.

EffectofAtomizingAirFlowow.pdf (464.8 KB)

[GnomeyByNature]

Ok, so according to what you say, if those nozzles only come one way or another, then based on some of my previous testing (non chamber testing), I likely have a siphon nozzle as it 100% worked as siphon and may or may not have worked (droplet size) with an unknown amount of low pressure.

Also tho, I wonder if my nozzle is different from the knockoff SS nozzles you tested because my nozzle has the flow adjustment on it and if I remember correctly, the ones you tested did not?

If you did have a flow adjustment, while altho this would be hard to replicate and not scientific (other than our laser hang method quasi measurement), would you try gravity (positive pressure) so that you have more to work with and if it felt like to much, just adjust down the fluid flow at the nozzle?

PS, got new net cups today and if they fit, might have a video for you.

[anon32470837]

@GnomeyByNature

Also tho, I wonder if my nozzle is different from the knockoff SS nozzles you tested because my nozzle has the flow adjustment on it and if I remember correctly, the ones you tested did not?

Mine did not have the restriction valve. These valves actually come three different ways. They should all work to restrict the flow, but the top one will have the finest control and will work best I think. The other two will be somewhat more difficult to adjust to any precision. They should still work though. You should be able to take yours apart to see what the needle tip looks like.

You should see a difference in hang times in a sealed chamber if its working.

From pg C5 in the SS catalogue:

@GnomeyByNature

If you did have a flow adjustment, while altho this would be hard to replicate and not scientific (other than our laser hang method quasi measurement), would you try gravity (positive pressure) so that you have more to work with and if it felt like to much, just adjust down the fluid flow at the nozzle?

You need to try it and see. If its easier for you to do the pressure feed option, then try that first. If you can get good hang times - AND - the correct over all flow rate, then you are good to go.

Remember you need to “fill the chamber” with mist AND have good hang times AND have a reasonable over all flow rate AND not flood the roots with too much direct spray AND have a reasonable droplet distribution.

You can test the flow rates easily. Just weigh the rez or a small feed tank before and after doing 50 -100 cycles. Just be sure the siphon height and/or the pressure stays the exact same all through the test. If you cant reproduce it, the results wont help much. Hang times and droplet sizes are more difficult as I have already gone over.

Have you calculated your chamber volume?

Looking forward to the video! If I have time, I have some new ones too…maybe…

[GnomeyByNature]

So I took this video before I saw your post but I wouldn’t have had time to do it 100% properly anyway, which I’m not necessarily promising I’ll ever do, but here is a lil something.

I will try to get some more in a few days with more info, cause right now, my air pressure is a guess at around 20psi, my nozzle stop valve is just barely open, I did this with some gravity (w/fluid solenoid), maybe approx 1ft higher than the nozzle.

I think my cycle here is approx 2 sec On and somewhere between 1:15-1:30 Off.

Chamber is the 55 gallon, however, I think it is actually bigger because I have 45, 45 degree elbow pvc pipes sticking out of it, so all those lil spaces I’m sure add up.

When I looked at it with a flashlight it looked like the entire chamber was filled, even when I took off a net cup, fog started coming out of the pipe.

As a reminder, I’m spraying up from the bottom center.

I think you can sort of see a lil bit of the hang time with this video, camera is also on the bottom pointing up, same with laser.

[anon32470837]

Looks like you are off to a good start!

Get those flow rate measurements after you get a timer hooked up so you know the exact ON and OFF times and can count an exact number of cycles.

Once you have that you can calculate a good timing schedule to start testing on live victims! Oh, wait. I meant plants