Oh, here is my proposed root chamber layout. Iāll start with the 30 gallon size, but plan to increase the height until Im close to 50 gallons total volume.
I have a plan to fire the nozzles alternately to reduce the over all flow while still having good coverage - I hopeā¦ more on that in a while.
I plan to fire 1 & 3 as a pair and then fire 2 and 4 as the second pair. The timing will be set to switch back and forth between the pairs every few minutes - maybe every 15 minutes or so.
Canāt wait to see this in the works!
Oh, the first thing that popped into my mind when looking at your drawing was āparticle acceleratorā. 
LOL! I like that 
Actually, I am trying to get the droplets to swirl around the chamber, so I guess this could be called a micro-droplet accelerator! Im targeting roots instead of nuclear particles, but close enough 
Im hoping that alternating swirl action will make for better, and more even coverage of the roots. The first pair of nozzles will circulate the mist clockwise, and the second will circulate counter clockwise. Im going to mount the nozzles near the bottom of the chamber then angle them mostly pointing up but tilted to they cause the swirling action.
The main reason for trying this alternating technique has to do with the catch 22 of HPA - at least according to Atomizerās theory.
The ultimate setup would provide a constant supply of droplets in the 50 micron size range - BUT - you do NOT want the roots to be overly wet or overly dry. If they have water beading up, thats too wet. If they get dry, well thats obviously not good either.
From what I have read, a large % of HP folks leave the nozzles on too long - according to Atomizers way of thinking. That means the roots are getting too wet by his standards. Then they leave the nozzles OFF for several minutes to let them dry out. So the roots go from too wet to dry, and back to too wet.
The result is roots that are little different from what you can get with LP aero or NFT type setups, etc, which are a lot less effort, and cost.
His goal is super fine fuzz on the roots, like in this pic.
Contrast that root to the ones I got in my LP cloner. These roots look good, and have lots of latteral growth, but do not have those super fine hairs.
His recommendation is to try to create an environment for the roots that is much more uniform, and does not go from too wet to too dry.
That requires very short ON times and shorter OFF times than most use. In order to reach his target numbers - a max of .06 ml/gallon of root chamber/discharge cycle. The trick with that low a flow rate is to also get good coverage of the entire chamber and all the root mass. For the size chamber I am looking at, that means ON times of around .5 to 1.5 seconds and OFF times of around 1 minute.
Thats ārelativelyā easy using AA because you can control the amount of mist better, and get better droplet sizes at lower flow rates and pressures. The trade off is cost. The nozzles start around $120 ea, plus a silent compressor, etc etc.
With regular hydrolic HPA nozzles, you can get good droplet sizes, but it requires higher pressures and you have to deal with significantly higher flow rates.
You need a decent sized chamber to allow the roots room to spread out and grow down. Its seems they can and will grow sideways in the air with no support.
The catch 22 is that large chambers typically need more than one nozzle to give good coverage of the entire root mass and chamber. More nozzles = more flow rate, and more droplets into the chamber at each cycle. That tends to over wet the roots.
By alternating pairs of nozzles, and reversing the swirl, Im hoping I can get the flow rate down to his recommended rate while still covering the entire chamber with a nice even mist.
I could jsut use shorter ON times, but you run into another catch 22 there. There is a certain amount of lag time in each of the parts as far as pressure increasing and decreasing during each ON cycle. This is due to flex and stretch in the tubing, plus the time it takes for solenoids, and the NO Drip nozzles, to open and close. They donāt open/close instantly. While they are in transition, the pressure at the nozzle will be ramping up or down rather than remaining constant. That means the droplet size, and patterns are also not ideal during those times. So the beginning and end of each cycle creates less than idea droplets and mist.
That means the shorter the ON time is, the worse the over all droplet quality is.
Thats a long winded way to say Im trying to beat the builtin deficiencies of inexpensive HPA hardware. We wont know how successful I am until some roots start to show up.
Just checked the babies and they are all three starting to show little white nubbins. The interesting thing to me is they are only showing up where I did NOT scrape the stem. Lots of folks recommend scraping, so I wonder if I did it wrong? Maybe too much scrape?
Looking forward to your progress here man. Now that I got the room build part of my thread out of the way Iāll be adding the start of the grow to it today and going into the various problems I experienced with my first run.
I spent quite a bit of time tweaking ON and OFF times and I was able to get the fine haired roots, they were beautiful (but fragile). I ended up with some root zone temp problems that caused root rot, and those hairs didnāt last long once it took hold. Hydroguard cleaned things up for me, but I needed to increase spray duration (and lower the temps on the chiller) in order to get temps under control. I also found w/ the short cycles I was holding water longer than I wanted in the lines/accumulator ā which also affected water temps.
Another few weeks and Iāll harvest, then I can do the root dissection to determine exactly what my next run with look like. No matter what Iāll be sticking with HPA though. Like you I love a good geeky challenge and even with all of the problems I had this run Iām still in love the growth rates. Good news is the next run Iāll be adding 4 soil plants from the same mother side by side, so we can compare HPA vs soil. We harvest one a day from the perpetual grow, so we know exactly how to maximize these from soil already, itās up to me to prove out the HPA increases and see if we expand this system beyond my test room.
I am looking forward to following your progress.
Heat is a major issue for me as well. I have to limit my growing to the cooler months. Im hoping I can at least test HPA cloning in the mean time.
Just found your new thread, so Im off to follow you there
Iām lucky that even during the hotter months my room maxes out at 80Ā° during lights on. During winter I actually have to run the baseboard heater to keep temps stable. (Even with the water cooler and lights kicking out heat.) The insulation in the room should help a lot this year, though.
At the beginning I was only running 2 QBs in the room so the clones didnāt get overly stressed from too much light, the room temps were low 70s ā but the root zone was constantly in the 90-100Ā° range. (And the sinks are double insulated w/ white reflective tops.)
Back in my racing days I used a product called Lizard Skin on my racecar firewall to prevent heat from baking me inside the car. Iām thinking I might have some laying around here yet ā might have to spray the outside of my tubs to see if that helps heat transfer.
Where was the heat in the root zone coming from if the room temps were in the 70ās?
Ive used Lizard skin before when trying to insulate a home made curing chamber when I was building carbon fiber glider wings. Its good when your trying to insulate hi temps that would melt regular foam - like on a fire wall, BBQ, etc. Plus, you can paint it on irregular surfaces.
Regular foam insulation has a much higher R rating though for a lot less money.
TBH I have no idea. Outside of radiant heat w/ no airflow I couldnāt think of any other source of heat. Even worse, one bed was hotter than the other.
Plant #1 (OC) ran super hot at the roots, the root looked like total shit, but the plant was perfect looking.
Plant #2 (BK) ran 10-15Ā° cooler at the roots, and the roots were beautiful, pearly white w/ fine hairs, but the plant looked like total crap.
With only a single (very strange) test under my belt w/ the new system Iām still not 100% solid on everything. Next time around I will be going in with a much more scientific approach.
Totally agree, I wouldnāt be buying this specifically for the beds, but since I have 5 gallons left over I think itās worth a shot. I am thinking of replacing my silver bubble insulation with foam, I should be able to cut them and fit it properly w/o issue. (And Iām sure I have 2 or 3 sheets left from the room build.)
Interesting mystery! I cant imagine the spraying process itself would generate any measurable heat unless the nutes were getting warmed up somewhere along the line, but I cant think where that would have been.
Is it possible the solenoids were over heating or some other component in the delivery system? That seems pretty unlikely given your parts list.
The pressure limit switch and the accumulator are not here yet, but I put together some of the parts temporarily just to see how it works.
The gizmo on the right side, in the larger red circle, is the solenoid type ULKA pump. It works perfectly and is even self priming if the outlet is not restricted, which is a nice surprise. You can see some folded paper towels under it. It sounds like your shaking a bucket of bolts at 60 hz when its sitting on the bench while running, but its not bad at all with just the paper towel as sound proofing. I doubt I will be able to hear it over the noise of my fans once its mounted properly, so thats good.
Moving to the left is the PVC check valve. I was stupid and assumed adapters would be easy and cheap - they are not! I should have gotten one with 1/4 push to fit. I spent almost $30 yesterday at Home Depot buying various adapters for this, and the pressure relief valve and the pressure switch and filter. It might have been cheaper to spend a bit more up-front and get everything I could in 1/4" push to fit from the get goā¦
Next is the pressure gauge and then the solenoid. Near the solenoid, you can see the pressure relief valve - not connected yet. The line then runs down to a 5 gallon bucket with one nozzle in it.
Turns out you can see mist against a red 5 gallon bucket, so I put an old 5 gallon fabric pot inside.
The mist looks good to me, but I have no way to tell what size the droplets are. Without the pressure switch, and regulator, and no accumulator, the pressure would climb rapidly to over 200 psi if I left the pump running. I had to switch the power strip on/off to control things even roughly. The pressure was still jumping between 40 psi and 140 psi, so this was not a good reference for how it will end up, but still fun
Its really hard to tell, the mist is hard to see unless the light is perfect, but I dont think these nozzles have much throw. I wont be able to tell for sure until I get things together better for some real tests. One of the first ones will be to measure the actual flow rates at various pressures. The plan is to weigh a plastic bag, then shoot mist into it for a fixed amount of time, then re-weigh the bag. I wont do that until I get the timers set up though.
Im starting to get excited!
Now to wire up timers and the DIY mosfet relay/switches. The timers come with cheap mechanical relays. I was going to replace them with solid state relays for better reliability, but they are $$. I bought enough mosfets, resistors, and schottkey diodes to build 4 of them for about $12 from Digikey. I can post the circuit diagrams if anyone is interested.
Well, I am having second thoughts about my nuclear dropletron accelerator idea. After seeing how the mist looks from the nozzle, I was having some vague doubts because the throw just wasnt there like with AA nozzles. Then last night, Atomizer and another long time HPA guy both shot down the idea pretty hard over on RIU.
After thinking about it some more, I have to agree. Even if I could get the droplets to swirl around the chamber the way I was thinking, my timing idea would leave parts of the roots getting too much water and parts getting too little. Even if I could get the average flow rate to the proper level, each discharge would be too much for some roots and too little for others, which is not optimum.
Im still going with the same basic design, just not alternating. Now its going to be down to how many nozzles will be ājust rightā. to het the good coverage but not too high a flow rate.
Hahah, I couldnāt stop myself from playing as parts arrived, either. Glad to see things coming together!
I was about wondering this myself, but it was a unique enough idea that I wanted to see where you ended up with it.
Thatās a really good idea. I will have to do something like this once Iāve got things torn down for cleanup. Please be sure to post the results, itāll be interesting to compare the data once I can measure my flow.
Iāve been looking for a good flow meter to add to the sensor collection, but I havenāt found anything less than $150 thatād cover what I am looking for. Maybe Iāll just bite the bullet and pick one up.
I got that idea from the same place I get many of my best ones - other people I actually got the idea from Atomizer, so the credit is his.
Its likely to be very expensive finding a flow meter that will work on this low a flow rate - less than 0.1 ml/sec or .000026 gal/sec isnt much. Plus, I wonder how well it will work on the short cycle times? Maybe a digital one? Oh, wait, you will have a lot more nozzles than I will, so a much higher flow rate. Still pretty low though.
Im just going to go with the plastic bag test results, and pretend they will remain consistent enough over the length of a grow The best Iāll be able to do as far as monitoring changes in flow rate - from blocked nozzles for example - will be based on watching how fast the rez drops over time, and occasional peeks into the root chamberā¦Well, to be honest, I expect to be peeking into the root chamber a lot!
Ok, the results are in, and its official - it makes NO difference how you clone as far as time to root goes - at least with this strain. Its been 10 days since I started this second batch, and one of them finally has new roots showing. Thats exactly how long it took the first time around, so none of the changes I made in the procedure, or timing, made any difference.
It will be very interesting to see if HPA can change that.
UPS lost my pressure switch, so now it wont be here until Monday. The accumulator tank will be here Tues. I can start serious testing after that.
Oh - I really need to stop ordering parts at 2AM when Im stoned. In addition to all the adapters IM having to buy, it turns out both of the timers I chose only have analogue inputs for setting the timers. One you have to turn a pot and the other one you have to hold down a switch for the time you want. Both are imprecise. Fortunately, they are easy to return via Amazon.
Liquid mass flow meter. A small one. On Ebay, one can sometimes find them used for low-price. They are very expensive new but have seen them under $100 used. And, since you are pressurized, that opens up the possibility of a mass flow controller on top of the that. Keep on eye on the specifications in particular the min/max flow rates and any pressure differentials by having one in line.
The pressure switch arrived today, but the timers and accumulator tank are still not here. Maybe tomorrow.
I have the root chamber roughly setup. After stitching two 30 gal pots together, the chamber is right at 45 gallons - 24" diameter x 23" deep.
The pressure switch cuts off the pump at around 100 PSI. and the reducer drops that to 80 PSI at the nozzles. I still need to fine tune the pressure switch cut on and off settings, but that will wait until I have the accumulator tank hooked up.
I decided to run some more tests to be sure the pressure switch and pressure reducer worked - which both seem to do just fine.
Then I put two nozzles on a single solenoid and did some spraying to see how it looked. The good news is the mist looks ok my eye.
The bad news is these āNo Dripā nozzles are NOT no drip 
They have the check valves inside, but they do not work the way they should. They start spraying at about about 20 PSI, but never shut off completely. The nozzles just continue to leak until the pressure drops to around 5 PSI. Thats never going to work well. I was under the impression that they wouldnt open until the pressure reached around 40 PSI, then they would close when it dropped to around 20 PSI. Either I have the wrong idea or these just dont work for crap.
They also dont put out as much mist as I thought. Im going to need at least 4 of them to fill the chamber with mist. That wont be a problem if I can get the timing down to around the 1 second mark, but if they drip like this, that kind of kills the DTW idea. Im probably loosing at least as much in the drips as in the mist.
Without the timer, Im having to switch the solenoids on manually, so no fog pics untl I get things a little more stable and hands free
Interesting side note on the latest clone babies.
Three days ago I took them out of the LP aero cloner so I could start building the new HPA system. Instead of tossing them, I just stuck them in a glass of the same water that I had been using in the cloner - PHed tap with a hint of nutes at PPM 300 or so.
One of them had a pair of new roots about 1/16" or 1-2mm long and the other two just had lots of white nubbins and bumps. At the same time, I cut a new clone and just stuck it in the same glass to see how it did.
Anyway, after three days in the jar, the roots on that one plant have only grown maybe another 1mm at most, and the other two still have not rooted.
In the aero cloner, the roots went from 2 or 3 mm to over 6" long in the same length of time, and the non-rooted ones all shot out nice new roots.
So, it looks like aero cloning is faster than a jar of spit water - at least for this strain.
I think I also forgot to mention that the humidity dome I tried did keep the leaves looking greener on the ones I covered, but it did not seem to help with the speed of rooting.
Grumble, gripe, piss, and moan. It took several hours over the last two days to find some new nozzles to try. The Hypro nozzles were recommended, but it turns out that Hypro is an Italian company that shuts down during the summer, and none of the US distributors have any in stock. Lead times were quoted from 2 weeks to 12 weeks depending on who I asked. I finally found one dealer who claims to have some in stock - but - the company has some very poor reviews for shipping on time and customer service. I ordered them anyway, and will keep my fingers crossed.
Then - I discovered that the accumulator tank I ordered is only rated to a max of 100 PSI - not the 130 listed on Amazon.
After more searching, I decided to try a water heater expansion tank. Its rated to 150 PSI working pressure and has a 5 year warranty - AND - its slightly less expensive.
Well, crap. The new tank arrived today and its damaged! (sigh) At least Amazon makes returns relatively painless, but I hate the delays.
Im making some progress on the control center at least. I have both timers programmed, but Im only going to be using one for now. Eventually, one timer will handle lights ON timing and the second will take over during lights OFF, but that wont be needed until I start a full grow. That probably wont happen until late Sept some time - after it cools down some.
Sheesh!!! I was just starting to post a pic of the board, and realized I forgot to make space for STC-1000 temp controllers. Ah, well, I have lots of time to re-do it now that the tank has to be sent back
Maybe I need to go pop some of my capsulesā¦
