No big changes, but steady progress. Im well into the balancing act stage of ON/OFF timing adjustments. I check the roots at least twice a day to see how its going. I look for droplets collecting on root tips and to see progress of fuzzies and if they are growing towards nozzles etc. I just changed the timing again. Im now down to 0.8 seconds ON by 50 sec OFF.
The roots are growing downward nicely so far with no signs of heading for the nozzles, so its time to start trying for more fuzzies. That means adjusting for longer OFF and/or shorter ON times. I dont want to get too dramatic with long OFF times, so Im lowering the ON time in small stages. Its also important to maintain as consistent an environment as possible, so I cant go too short on the ON time or the chamber doesnt get properly filled with mist. This is all judgment calls and trial and error. You make a small change, then watch to see how the roots respond, then make more changes.
No LITFA at this point!
It only takes a few hours for the roots to show changes. Here are some pics comparing the plants from yesterday to today. Its cool to see how much change there is in the roots in just one day at this stage. Its not nearly as dramatic later in the grow.
Im really taken with the whirly bird baby for some reason. It seems to be doing at least as well as all the others. I read somewhere that they can loose the three finger thing if you top them, so Im probably not going to do that unless they look too wierd or there is some other problem with the three finger thing. We will see.
Im not sure what the reason is, but the other two babies want to droop their leaves much more than the whirly baby. Humidity maybe? Its been staying in the 35-45% range lately when light ON.
Thanks, I will definitely look at that possibility! So you are saying replace the pressure switch on the air compressor with one that turns on at a lower psi?
Minor up-date. Everything is going well so far with no major issues.
One more or less minor issue is the float valve in the siphon tank. It works, but the water level is too variable for my liking. Actually its probably working just fine for any other application. In this case though, I would really like to keep the level plus or minus 1/8" and its actually more like ± 5/16" to 3/8".
If I could keep the water level an 1/8" below the point where the nozzles start to drip constantly, I can lower the air pressure down to 4 PSI and get good mist. When the level drops more than that, the quality of the mist cycle goes down, and I need to up the pressure to 5 PSI or even 6 PSI, depending how low it gets, to keep the same quality. Its not a huge difference, but Im anal about getting a good mist environment, so it irritates me.
Plus, I have been trying to measure the exact flow rate for two days, now that Im using the siphon tank, and its just not working. The float valve sticks closed for a minute or three or sticks partly closed, and the water level drops 3/8" before suddenly starting to catch up. That sudden catch up draws in maybe 50-75 ml of water in just a minute or so, which inflates the flow rate drastically during that time, and its really low when its stuck. I only have a 150 ml graduated container to do the measurements with, so 50 ml is a huge error margin. Im going to have to accurately calibrate my rez and do the tests over several days as the rez draws down.
The plants look fine and are starting to grow some, but still short. The big girl is showing the most space between nodes and the whirly bird is very tightly stacked.
Roots are doing fine with a reasonable amount of fuzzy hairs, but Im going to keep lowering the flow rate until I get more. Right now they are growing mostly down, but there is a good bit of sideways growth. I suspect I will need to do some trimming/training in a week or two.
The babies are perking up a bit and starting to show some stretch - a little. The roots are getting long and still only partly fuzzy. They are maybe half way to the floor now. When they get closer to the bottom Im going to try some more root trimming to see if they start growing sideways like last time. For now, Im still sloooowly lowering the flow rate while playing with the ON timing. They are still staying a little too wet - thats why they still dont have total fuzzy hairs and are growing down more than sideways. In any case, the leaves seem to like this so far,
Here is a new video of what the mist looks like with roots in the chamber. The timing is 1 sec ON x 65 sec OFF. The video starts about 15 seconds before the cycle starts and goes for about that long after, so you can see how much mist is left after 65 seconds of hang time. I Like the swirling action.
Here are some leaf and root stills. No huge changes. Im collecting still images from the cam inside the tent and plan to do some GIFs when Im feeling better. Its hard to see changes when you look at the plants two or three times a day, but they show up well in the time lapse videos.
I was just looking at the roots again and noticed that the whirly bird plant (whorled phyllotaxy) has the smallest set of roots. They are also the smoothest = least amount of fuzzy hairs. After looking things over closely, it looks like the nozzle next to the big girl in back is pointed too directly AT this one - keeping it too wet. Ive changed the angle so the nozzle points more off to the side.
Ive also continued lowering the flow rate by changing the timing. Im now at 0.8 seconds ON x 75 OFF.
Edit: I forgot to add - the roots have all gotten down to within 4" or so of the floor, so I trimmed all three off a little. It will be interesting to see how they respond this time. Im hoping this forces them to throw out more side shoots and fill out to the sides.
@anon32470837 while I’m trying to get up steam to reply to your huge and very useful answer in the previous thread (by the way, would it be better to put reply here to keep everything in one place?) I would like to ask why did you choose #8 nozzle? As far as I can see its little siblings have better (lower) both liquid and air flow rates. Can’t find any info about spraying distance though.
At the same time I’ve found this study. It contains droplets diameters distribution information for 30610-1 nozzle (the stainless steel brother of 30609-1 brass one). This information gathered for diesel fuel but still might be useful.
Yes. Lets keep it here for that reason - plus I keep makeing changes and trying different stuff, which will all be posted here.
That was largely just a shot in the dark, but I based it primarily on the over all flow rate. I was originally thinking I would use fewer nozzles, so needed/wanted a higher flow rate. Also, if you look at the ratio of the liquid to air volumes, the smaller nozzles put out a lot more air to get the same amount of liquid into the chamber. I was initially thinking like you, that the lower flow rates would be best, but then I worried that the extra air flow might dry things out too much by the time I finished “filling the chamber with mist”. I dont really know if thats true, but the other factor was cost. I figured I would need more nozzles if the flow rate was reduced, which equaled more $$. Im on a stupid cheap budget.
Yeah, I couldnt find any studies that had distance info or SMD. I thought I had a reference on SMD, but I cant find it. That study you found looks like the nozzle is “hollow cone” based on the distribution pattern. I thought they were all solid cone and had no idea they had internal swirling.
I thought these Delavans were solid cone as far as I can tell - of course, my test equipment consisted of a piece of card board as a target 18" away from the nozzle and they used slightly better technique and hardware and at a much closer distance. There is a LOT of good info in there and Im going to need more time to re-read it though. Good find!!!
It turns out that going down to 0.8 x 75 was too low a flow rate. I started to see some air pruning of root tips in several places, so I bumped it back to 0.9 ON time by 65 OFF for several hours. Im now back to 0.9 x 75 and watching closely.
It feels like I need at least that 0.9 to really fill the chamber, so now its a matter of playing with the off time to tease the roots into making more fuzzies.
I have decided that I dont like how I positioned the nozzles in relation to the net pots. Im debating if its worth the stress to try to move them or if I should just let it go until the next grow.
Gotta run - more later…
Oh - here is the Delavan chart for easy reference.
When I built my HPA and needed a sub-second timer I had to build my own. I’m pretty sure my HPA thread has all of the details of the build – timer, 12v LED driver, and project box. Took about an hour to put together and ran perfectly though all of my testing. (It’s still in place, just haven’t used it in a while.)
Sorry @Badfishy1 - I didnt get the question first time around. Im cheap compared to @SuperiorBuds setup. The timers I use are super cheap. They only do tenths of a second, but that seems to be working fine so far. I have two of these from Amazon.
One of them is starting to act up, but still works. The buttons are getting to where they dont always work first time and I have to push harder. Its been in constant use for over a year though, so not bad for the price. I just ordered another one to have a backup.
I like these in particular because they use solid state relays instead of mechanical relays. MTBF should be much longer.
But now I has to rethink the whole idea… As I’ve said before I was thinking to put nozzles somewhere at the bottom of the chamber and spray with flat fan in parallel to the bottom. This in theory would give me a good mist, make an air fence for the roots tips and don’t intersect with the main roots zone. But even the lowest cone angle (30 degrees with huge air waste) would either hit roots (if I position the nozzle with the bottom side of the cone in parallel to the chamber bottom) or hit the chamber bottom side and I would waste a lot of mist (if I put the top side of the spraying cone in parallel to the chamber bottom) or even both.
I believe it’s a rule - to not interact roots in any way, am I right?
If you’d be able to find or measure spraying distance it would be amazing. May be it would be worth to go with #9 positioned up and just increase chamber depth a little, but only if it sprays not too far.
I think the effective throw distance with these nozzles, using a siphon tank and 5 to 6 PSI, is probably around 1 meter. Maybe 1.5 at most.
Yeah, the challenge is trying to match up all the variables and still follow the basic “rules” of aeroponics as per Atomizer. The root chamber is one of the key things to sort out.
In your case - with strawberries - you may be able to get by with a smaller root chamber as far as depth, but I dont really know for sure. Cannabis roots seem to be able to fill as much space as you give them. They also have the ability to defy gravity and grow in any direction - up and sideways are no problem and they will do their best to get to the source of the water.
Plus, as you said, Atomizer says to NOT spray directly at the roots. However, thats not realistic unless you have a huge root chamber. In my case, the chamber is 24" in diameter x 28" tall and I have almost filled it with roots from a single plant. In every single grow so far, the roots have been in the direct spray to one degree or another. Plus, as they grow and fill the chamber, there it is just impossible not to spray them directly to some degree.
I think maybe I should back up from my earlier comments about spray hitting the walls etc and being super worried about throw distance. Unless you have a huge space for a huge chamber, your just going to have to fit the nozzles in as best you can and see how it goes.
I do think the Delavan nozzles will work better in small spaces though - mainly because of the lower air pressure. That lower pressure means lower velocity and less distance than a similar nozzle operating at two to ten times the air pressure. Your just going to have to accept the loss in efficiency of some portion of the mist being lost on the walls of the chamber.
Even with those losses, your going to end up using less water and nutes than any other form of hydro. Im averaging about 1 to 2 gallons a day in water use. Early in the grow, 95% of that water is lost. Even late in the grow when the chamber is filled, I still throw away maybe 1/2 to 2/3 of the water. The plants just dont need that much water when doing AAA or HPA. The waste comes from the need to “fill the chamber with mist”.
The other thing is in early growth, you may need to spray directly or close to directly to give the roots a chance to adapt to the new environment from how ever you start the seeds.
I would suggest you decide first how much space you have to work with for the chamber. Be sure to allow room to get into it for service, repair, adjustments etc. Then make you best guess on number and placement of nozzles and give it a try.
At worst - if you end up spraying the roots to directly and they stay too wet, you will end up with nice roots similar to LPA roots. They will be smooth, but still healthy, so not a total loss.
If you do end up having to spray directly, you can shorten up the ON time and extend the OFF times. That does work but is less than ideal.
The ideal situation is to create a mist environment where the droplets are the correct size range, AND they are kept at a constant, uniform density. You dont want a wet/dry cycle where the roots get too wet, then you wait for them to dry out, then get them wet again. That will work, and its how most folks end up doing it, but the closer you can get to creating that uniform, constant level of mist, the happier the roots will be.
So far, I have NOT managed to get to that uniform ideal environment. I have always ended up spraying the roots to one degree or another with the resulting wet/dry cycle.
Im trying to say dont get too discouraged because you cant get it perfect. Plants are pretty forgiving for the most part if you get in the ball park
I would try to come up with the largest root chamber you can fit in the space. Then arrange the nozzles as best you can. If we assume that strawberries will have fairly short roots, then maybe you would be better off with the delavan nozzles on the narrow end of the chamber, near the top shooting down the middle. Then arrange the plants along either side.
Maybe something like this. Depending on the size, you might be good to have each nozzle on a separate timer so they fire alternately. I would still mount them near the top of the chamber. Roots will have an easier time growing down to get to the mist if you shoot along the bottom. Shooting parallel to the top should be a little more efficient as the mist will drop to the bottom anyway.
Looking down from the top if you use a rectangular box type chamber.
Im thinking of changing my setup for the same reasons we have been discussing - direct spraying of the roots.
I set it up like in the picture below - three nozzles and three net pots. If you number the net pots 1,2,3, then the nozzles closest to each net pot are also 1,2,3. The way I have it now, nozzle 1 sits close to pot 1 and points more or less towards pot 2. Nozzle 2 points to pot 3, etc. I can turn the nozzles so they point closer to or further away from the pots, but I only have a limited range I can turn them because they are too close to the net pots.
This is how I want to change it. Moving the nozzles to these new positions will mean I have more room to turn them away from the net pots after the roots get established, but I can shoot right a them early on. It also means a longer distance from the nozzle to the net pot. I wont get as much swirling action, but still should have excellent coverage.
I will still leave them near the top of the chamber. Having them down low means they get swallowed by the roots too easily.
I did it - changed the position of the nozzles relative to the net pots. Turned out to be easier than I thought it would be. Thats mainly because I realized I could just rotate the foam lid, with the net pots in it, instead of trying to remove and reposition all the nozzles, and do all the plumbing changes that would require.
Well, it wasnt quite that simple, but much easier and faster than I was worried it would be. I had to re-work the access hatch and Im still not happy with it, but it will have to do until the next grow. I will probably completely replace the lid next time. The access hatch is way to close to that one pot, and there are other things that could be improved as far as access, sealing and light proofing. I think this will get me through this grow ok.
I over sprayed the roots before starting, but they were only without mist for maybe 15 minutes, so Im not worried. I set the timing back to 0.9 x 50 for now. I will be checking often over the next several hours before making any changes. This new positioning will change how the mist interacts with the roots quite a bit, so I want to over spray until Im sure the roots like the changes and angles of the spray. I have turned all three nozzles so they point like in the second drawing above, but they are all turned slightly to the left of the opposite net pot. There wont be as much swirling as before, but Im ok with that considering the trade-offs. But - we will have to see how this works over time. I have been surprised by unintended consequences after making changes more than once!!
I forgot to post about other changes I made over the last couple of days. Mainly, Ive started LST on the whirly bird and FIM’ed both of the others. Well, I think I FIM’ed them. Might have missed the “miss” part and actually topped them, but cant take it back now I did NOT top/FIM the whirly bird. I read that can stop the three branch thing, so Im gonna leave it and just LST that one. The others will get LST from this point on. I’ll be adding the scrog screen once they start to get taller.
I’ve just decide to give a try to Chinese nozzles (SU13 internal mix and SUE15 external mix, both flat fan). Seems that SU13 nozzle sprays liquid almost with the same air\water ratio as #8 delavan nozzle. At the same time SUE15 has much shorter D distance, so it could be that I’ll need less ON cycle timing to mist the chamber (as less mist would directly hit walls\floor). Of course, if they are going to work at all. Docs says that it is possible to change atomization characteristics by reducing water pressure and adding more air pressure. Will see.
I’ve made a simple table to check liquid\air ratios, here it is:
But I don’t give up on these Delavan nozzles. It’s very likely those nozzles won’t work at all. The only sad fact is that I’ll need to wait at least a month for each order to be delivered (both Chinese and Delavan). Or spend twice as eBay price to buy them in my country.
By the way, didn’t find any info on Delavan AA nozzles. They exists in catalogs but nothing on sale.
I have not had enough coffee this morning, so maybe Im reading that chart wrong, but some of your numbers dont look quit right to me. Have you had enough coffee this morning? One of us is off and its probably me
For example, in some places the liquid flow rate of the Delavans goes down with increasing pressure, but for others it goes up? You also show the Delavan -9 and -11 as having the same air flow rate, but they are not the same on my chart? Also, where did you find info on flow rates at 0.7 bar? My chart only goes up to 0.35 bar.
Im wondering if you got some data in the wrong cells on the spreadsheet maybe?
On the Chinese nozzles, you seem to be comparing them at very different pressures and flow rates. The 15’s seem to have similar liquid flow rates at much lower pressures. They would seem to me to require much larger SMD on average, but maybe not.
Anyway, Im not following that chart very well.
Going back to the Delavans, and looking at that PDF you posted earlier, the Delavan they tested (the lowest flow rate) looked to have SMD numbers mostly down in the sub 20 uM range. That makes sense to me. With the same air pressures and lower flow rates, that means the SMD would have to be smaller. So the higher number Delavans will have larger SMD values.
As far as adjusting/changing atomization by changing air and liquid pressures, the Delavans work the same way. Its easy to see the difference in my setup when I increase the air pressure from 4 PSI and go up. The average droplet sizes get smaller and the number of droplets increases - visible as higher mist density and longer hang time. So the Delavans are also adjustable in the same way, but they dont have little needles to change flow rate - you have to change liquid pressure by adjusting siphon height. Lower pressure (higher siphon height) lowers flow rate which should also lower SMD = finer mist.
All of that said, those Chinese nozzles may work very very well. The ones I tried did not siphon at all, but I didnt test them with pressure feed on the liquid. My head height was very low so the liquid pressure was not enough to get any flow at all.
Are you going to use a pump on the liquid side with the Chinese nozzles or just increase the head height of the rez?
I was thinking I found some somewhere, and they were $$$, but I dont remember for sure.
Have you tried contacting the sales dept?
That sucks that it takes so long for you to get nozzles. Are you going to order one of each one so you can test them all at once?
By the way, dont let me stop you from trying those Chinese nozzles - or doing anything else you want to do. I am a long way from any kind of expert, and I am looking forward to seeing your results! I may want to borrow some of your best ideas
I did NOT top/FIM the whirly bird. I read that can stop the three branch thing, so Im gonna leave it and just LST that one. The others will get LST from this point on. I’ll be adding the scrog screen once they start to get taller.
