HPA optimum root chamber size

HPA root chamber

  • Tall and skinny

    Votes: 2 40.0%
  • Short and Fat

    Votes: 0 0.0%
  • Tall and Fat

    Votes: 3 60.0%

  • Total voters
    5

MI.BUDZ

Active Member
Building my first hpa SOG grow and can't decide on the root chamber size.
Separate LPA rooter with larger clones.
7-10 days veg and flip straight to flower in these chambers, 100% DTW.

Thoughts.... Comments

First pick:
  • Top:
    • Inside: 9 1/8 x 9 1/8"
    • Outside: 9 15/16 x 9 15/16"

  • Bottom:
    • Inside: 8 1/8 x 8 1/8"
    • Outside: 8 3/8 x 8 3/8"

  • Height:
    • Inside: 16 3/4"
    • Outside: 16 3/4



Second pick

Top:
  • Inside: 9 1/8 x 9 1/8"
  • Outside: 9 7/8 x 9 7/8"
  • Bottom:
    • Inside: 8 1/4 x 8 1/4"
    • Outside: 8 1/2 x 8 1/2"
  • Height:
    • Inside: 13"
    • Outside: 13 1/8"




 

Larry3215

Well-Known Member
Im a long way from an expert - about 25 days into 12/12 on my first HPA grow after 5 weeks of veg - but those sizes all look really small to me.

My chamber is made from two 30 gallon fabric pots stitched together to form a chamber 24" in diameter x about 26" tall or so - roughly 48 gallons total volume.

My main root 'ball' is umbrella shaped and is almost completely cutting the top part of the chamber off from the bottom. The roots have grown out to the sides so they are touching the walls on about 3/4 of the way around. One nozzle is buried in the roots in back where I cant get to it, and a second is almost buried. I started with only three nozzles, which wasnt enough. Ive added two more over the last few weeks as the root mass grew to fill the space and crowd the existing nozzles. I had to add the last one down low to feed the mat on the floor because not enough mist was getting to the bottom any more.

The umbrella is a solid 24" across by roughly 10"-12" thick at least - with long roots hanging down from the solid portion. Im sure it would be wider than that if the chamber was larger. There is also a layer growing on the floor of the chamber, and up the sides, that if flattened out, would be about 28"-30" in diameter by an average of 3" thick.

I still have about 4 to 5 weeks of 12/12 left.

Oh - this is a single C99 fem from seed. The tent is 28" x 38" x 48" inside. 320 watt LED's. Im also 100% D2W. Flow rate at the moment is around 1.7 gallons per day for the one plant.

Plant looks good and I have a lot of white fuzzies, but also some brown algae crap and some areas of plain hydro roots. The roots are a long ways from perfect, but Im happy for a first time with HPA.

They are still growing though it has slowed down some this last week. If they keep growing, I may have to trim them back, but I really dont want to do that.
 
Last edited:

MI.BUDZ

Active Member
Damn man!!! Sounds like you are grow a freekin TREE with that root mass. NICE. I’d love to see some pics of that, for sure.

Unfortunately, I won’t be able to get the root masses that large in diameter due to the tight SOG and I want to have the flexibility to remove a plant if it does go hermie. I have 8-1/2’ ceiling height and can go with taller root zones though.

Figuring 36” max from light to canopy (LEDs)
24”-30” plants max (SOG) single colas
24” + root chambers + drain piping

Here I’m @ 90” with roughly 12” to go.

Thought about opening the bottom of longer buckets, wrapping the bottom with fine mesh to allow for drainage and O2. I still want the flexibility to remove a plant and not having them intertangled.

Your thoughts...
 

Airwalker16

Well-Known Member
That's the one thing I would find annoying in HPA is no control of the roots in the open air environment.
 

Airwalker16

Well-Known Member
Damn man!!! Sounds like you are grow a freekin TREE with that root mass. NICE. I’d love to see some pics of that, for sure.

Unfortunately, I won’t be able to get the root masses that large in diameter due to the tight SOG and I want to have the flexibility to remove a plant if it does go hermie. I have 8-1/2’ ceiling height and can go with taller root zones though.

Figuring 36” max from light to canopy (LEDs)
24”-30” plants max (SOG) single colas
24” + root chambers + drain piping

Here I’m @ 90” with roughly 12” to go.

Thought about opening the bottom of longer buckets, wrapping the bottom with fine mesh to allow for drainage and O2. I still want the flexibility to remove a plant and not having them intertangled.

Your thoughts...
Roots will find their way into and through any mesh you could possibly ever use. No matter how small the Hole size. You'd be better off just cutting 2 very thin slits 1/4 of the circumference(90*)along the edge of the bucket bottom where it meets the wall. I wouldn't make them more than 1/8" wide slits. Also, you could just see if the water pools in the center or the edges of the bucket and drill a few tiny tiny holes there for drainage.
 

MI.BUDZ

Active Member
Thanks Airwalker.
I have researched it and the bottoms do drain to the center. I also thought about letting the water free fall through an Air Gap into a Catch basin similar to Sanitary Plumbing Applications for food service operations. Maybe this would help air trim them and provide a little extra O2 in the chamber.
 

Larry3215

Well-Known Member
Damn man!!! Sounds like you are grow a freekin TREE with that root mass. NICE. I’d love to see some pics of that, for sure.

Unfortunately, I won’t be able to get the root masses that large in diameter due to the tight SOG and I want to have the flexibility to remove a plant if it does go hermie. I have 8-1/2’ ceiling height and can go with taller root zones though.

Figuring 36” max from light to canopy (LEDs)
24”-30” plants max (SOG) single colas
24” + root chambers + drain piping

Here I’m @ 90” with roughly 12” to go.

Thought about opening the bottom of longer buckets, wrapping the bottom with fine mesh to allow for drainage and O2. I still want the flexibility to remove a plant and not having them intertangled.
Im not sure what qualifies as a tree. My stem at the base is a little over 1". The tap root is maybe 1 1/4" in diameter, but its hard to see now.

Im not sure how to handle SOG in this situation. Thats one reason I went with a single plant. If you manage to get fuzzy hair roots, they stick together like velcro, and you cant pull them apart without damaging the fine hairs.

The only way I know to get the roots to grow straight down is to over water them, but that means no fuzzy hairs. Plain hydro roots are not bad, but I started this specifically to get fuzzy roots. Ive seen pics of roots that grew mostly down, and had fuzzies, but I have not been able to dial things in that well. I either get fuzzy roots that want to grow any old direction - mostly towards the nozzles - or I get regular hydro roots that want to just grow down.

I agree with Airwalker - no mesh will stop roots unless its fine enough to stop water. Thats why Im using fabric pots. When the roots try to grow through the fabric, they automatically get air trimmed.

The fabric pots do several critical things:
1) Evaporative cooling keeps the root chamber at a reasonable/safe temp. I actually have to heat the chamber so its not too cold. With the small heater and a temp controller, it stays between 70F max and about 68F minimum at the top of the chamber. The bottom stays about 3 deg cooler.
2) They breath and let O2 in, so you dont have to cut holes, etc.
3) They air trim roots that try to escape.
4) Excess nutes drain out the bottom and are easy to collect. I still need to clean roots out of the drain every so often though.

I have a build thread in the Aerogardener forum with pics of the chamber.

https://www.rollitup.org/t/trying-to-do-the-math-on-an-affordable-hpa-system.973198/

Here are a few recent pics. Im doing scrog, but its not my best training effort as far as level canopy. One annoying thing about white fuzzy roots is that even the slightest browning or even white roots without hairs, look very brown. There is just too much contrast - especially when using flash. The roots actually look much better by eye than the pics suggest.
 

Attachments

MI.BUDZ

Active Member
WOW man... those are some serious fuzzies!!
What pressure and micron are you running? Also was wondering where and which direction your nozzles are pointed.
 
Last edited:

Larry3215

Well-Known Member
Another thing to consider with small chambers is where to put the nozzles and how many to get good coverage.

Like I said, I originally went with three nozzles spaced around the chamber about 16" down from the top - pointed almost straight up. However, the roots grew in three big, interlinked lobes - oriented towards the three nozzles. It looked like three socker balls melded together almost like a three cornered hat. That worked great until the roots grew too big and started to block the mist pattern and finally cover the nozzles.

So, I moved the two I could reach up to the top of the chamber - shooting mostly horizontally, and added a third one up top to replace the mist lost by the hidden nozzle. Later, after they got even bigger, I added the lower nozzle because the mat on the bottom was looking too dry.

With small chambers, you will have little choice but to spray directly on the roots - with no room to maneuver as they grow. Its harder to get fuzzies when you are directly spraying the roots. They tend to stay too wet and form hydro roots instead of fuzzy roots.

Something to think about.
 

Larry3215

Well-Known Member
WOW man... those are some serious fuzzies!!
What pressure and micron are you running? Also was wondering where and which direction your nozzles are pointed.
Thanks :)

Im running around 135 PSI into the accumulator tank. The pressure reducer is set to around 105 PSI going to the nozzles. Thats because the solenoids Im using tend to fail open much above that pressure. They are rated to 118 PSI, and that seems to be a hard limit.

Im using 0.020" SS nozzles from these guys at the moment. I have not tried very many, but these are my favs at the moment.

https://www.cloudtops.com/cloudtops/stainless_steel_fog_nozzles.html. Im using the 35PSI springs in the ADV valves and they have SS swivels that are very handy to fine tune where they point.

https://www.cloudtops.com/cloudtops/stainless_steel_fog_nozzles.html

Ive also used Aeromist SS nozzles that were 0.024" and they worked ok too, but were more prone to clogging (they have a pin inside) and had slightly larger droplets - less hang time, but not by much. I have a droplet size chart from them someplace, but cant find it at the moment. IIRC, the droplets are claimed to be in the 50 micron and smaller size range more or less. Im not sure I believe that 100%. Most of the droplets fall in under 30 seconds, but a fair number hang for over 1 minute.

Im currently running 0.9 seconds ON and 44 seconds OFF with a total flow of around 1.7 galls/day.

My biggest problem is I have algae in my water and floating around in my air. I live in a rain forest, so mold, algae, etc are just always around. I added an RO filter, which helps, and Im running pool shock, but its an up-hill battle. Im getting a UV sterilizer to add to the rez today. Hoping that helps keep these thngs more under control.
 

Larry3215

Well-Known Member
Building my first hpa SOG grow and can't decide on the root chamber size.
Separate LPA rooter with larger clones.
7-10 days veg and flip straight to flower in these chambers, 100% DTW.
Hows the project going? Im curious to know what you decided on all the various details.
 

MI.BUDZ

Active Member
My 8’x13’ sealed and insulated room is nearly complete. All self performance. Once the DW is complete, I’ll be lining the entire room in panda. Going to run double entry. First entrance will house all controllers above cabinet wall mounted, under cabinet rez, twin iCloud 6” fans and mountain air filters pulling negative air in with backdraft damper and second with MA filter discharging exterior with option to recirculate via damper. Both running off the same controller for room balancing. Interior scrubbing will be handled by an 8” MA.

OP parts continue to roll in. Currently the room is holding @ 66*. I’m going to start with 27 gal totes wrapped in foil insulation on a wooden stand. They will be elevated just enough to get positive drainage to DTW basin to be checked prior to discharge. Pump to discharge via 12v pump and 3/8” line.

Going to start /try Cloning with HPA opposed to LPA and led lighting.
1 tote will house 12 plants, to start. Really haven’t found much documentation regarding HPA cloning. The thought is the plants could go from cradle to grave in same chamber with alternating rez’s. One for clone and early flower and second for flower to finish. Setting the stage for a perpetual setup.

Your thoughts on the HPA cloning...

SOG & SCROG simultaneously as test
Tote1: 1- plant, 2 nozzles, 1 solenoid (mom to be)
Tote2: 2- plants, 4 nozzles, 1solenoid (SCROG moms to be possibly)
Tote3: 4-plants, 6 nozzles, 1 solenoid (SOG test)
Based on flow calculations going to have to get a sub second timer.

Any recommendations w/o having to build one?

Going to start with 1- 2000w led centered and T5 HO with red enhancement angled around the sides. We’ll see...

Going to run all MegaCrop start to finish DTW.

The 8855 pump and 20gal accumulator will be the heart and sole of the OP running 100 - 115psi with .8 gph nozzles. Later flow tests will determine the starting point. In that size chamber I am thinking 3-4 heads max if I can’t get to @ .5-.7 sec timing. Also based on hang time of mist.

At .8gph each head would deliver around .0002 gallon per second.

4 heads at .0008/ sec
At 1440 minutes/day at 3 minute intervals at 480 cycles/ day I would only be at somewhere around .38 gal/ day which isn’t nearly enough unless I am missing something.

Again, what would be your recommendation regarding a timer w/o having to build one?

Most parts running 120v but could adapt to 12v easily.
 
Last edited:

Larry3215

Well-Known Member
My 8’x13’ sealed and insulated room is nearly complete. All self performance. Once the DW is complete, I’ll be lining the entire room in panda. Going to run double entry. First entrance will house all controllers above cabinet wall mounted, under cabinet rez, twin iCloud 6” fans and mountain air filters pulling negative air in with backdraft damper and second with MA filter discharging exterior with option to recirculate via damper. Both running off the same controller for room balancing. Interior scrubbing will be handled by an 8” MA.

OP parts continue to roll in. Currently the room is holding @ 66*. I’m going to start with 27 gal totes wrapped in foil insulation on a wooden stand. They will be elevated just enough to get positive drainage to DTW basin to be checked prior to discharge. Pump to discharge via 12v pump and 3/8” line.

Going to start /try Cloning with HPA opposed to LPA and led lighting.
1 tote will house 12 plants, to start. Really haven’t found much documentation regarding HPA cloning. The thought is the plants could go from cradle to grave in same chamber with alternating rez’s. One for clone and early flower and second for flower to finish. Setting the stage for a perpetual setup.

Your thoughts on the HPA cloning...

SOG & SCROG simultaneously as test
Tote1: 1- plant, 2 nozzles, 1 solenoid (mom to be)
Tote2: 2- plants, 4 nozzles, 1solenoid (SCROG moms to be possibly)
Tote3: 4-plants, 6 nozzles, 1 solenoid (SOG test)
Based on flow calculations going to have to get a sub second timer.

Any recommendations w/o having to build one?

Going to start with 1- 2000w led centered and T5 HO with red enhancement angled around the sides. We’ll see...

Going to run all MegaCrop start to finish DTW.

The 8855 pump and 20gal accumulator will be the heart and sole of the OP running 100 - 115psi with .8 gph nozzles. Later flow tests will determine the starting point. In that size chamber I am thinking 3-4 heads max if I can’t get to @ .5-.7 sec timing. Also based on hang time of mist.

At .8gph each head would deliver around .0002 gallon per second.

4 heads at .0008/ sec
At 1440 minutes/day at 3 minute intervals at 480 cycles/ day I would only be at somewhere around .38 gal/ day which isn’t nearly enough unless I am missing something.

Again, what would be your recommendation regarding a timer w/o having to build one?

Most parts running 120v but could adapt to 12v easily.
I have only a little experience with HPA cloning, but it works fine as long as you have good timing and keep the stems wet, but I had better luck with LPA cloning.

Make sure you have a good, easy way to check the roots regularly. You will be adjusting timing a lot in the early stages of growth. However, be sure your access point is air tight and light tight. HPA roots dont like either one.

Which nozzles are you using? Do they have ADV's (Anti-drip valves)? You really need ADV's on each nozzle at a minimum, and/or one solenoid for each nozzle - placed as close to the nozzle as possible - preferably both. If not, then your mist quality will suffer - a lot. I tried it your way and it didnt work well at all.

Say you have a 1 second ON timing. If you have several nozzles sharing a single solenoid - especially if they dont have ADV's - then the nozzles will start flowing while the pressure is still building in the tubing and it will continue flowing long after the solenoid closes. When I had lots of tubing between the solenoids and nozzles, and no adv's, I might have the timer set to 1 sec ON time, but testing shows an actual flow time of up to 1.5 seconds. The more tubing you have the longer the run-on flow time.

This results in your mist cycle having too large a droplet size at the beginning and end of each cycle and will raise your flow rate - potentially a lot when compared to a nice crisp, clean on/off cycle. Mostly though it just wastes nutes and makes for plain, non-fuzzy roots. You could easily see 50% to 100% higher real flow rates than the math would suggest. Those over size drops wont hang and will result - at best - in regular hydro roots rather than fuzzy roots. You will have a very hard time "dialing in" the timing because the roots can never see a uniform droplet size and the majority of droplets will be far outside the best size range - 20-80 microns.

You should do some flow testing to see what your actual flow rates are. You may be very surprised at what you see. I also recommend you use a camera to take video of the mist cycles. Then watch the video in slow motion or frame by frame. You will be able to see how crisp the on/off cycle is, if there is run-on flow, or major big fat drips, etc. I had to do it in a dark room with narrowly focused LED flashlights or cat toy lazers. You will want a black background so the mist shows up well.

Here are a few of my test videos. I think the timing was set to 0.7 sec ON, and around 1 minute off, but dont remember for sure. You can easily see most of the mist goes straight to the bottom, but some hangs for much longer. Those are the smallest droplets. So, I may be flowing at .8 GPH, but maybe only .5 gallons of that is "hanging" as usable, quality mist.


Here is an earlier test.


and these are Hypro nozzles - which sucked big time for me. The ugly LED is so I can tell exactly when the timer kicked ON/OFF so I could compare the mist quality to the time. You can also see large droplets coming from the Hypros. Thats due to their crappy ADV's mostly. The flow rates measure way above the stated .8GPH. Closer to 1.2 IIRC.


Your totes will work, - many others have done that - but Im afraid they are still too short. I think Atomizer recommended 16" minimum height and I think that is too short. You will want to tip them so no water stands in the bottom if possible. Other wise, you will end up with puddles. That may not be bad, but again - excess water means no fuzzy root hairs. If you are using aquarium pumps to empty the totes, you're going to have deep water in the bottom. Thats not a deal breaker, but the roots will go straight for it and it reduces the vertical room for fuzzy roots to form. Again, not a deal breaker, but not ideal if you want fuzzy hairs.

Im using these timers at the moment. They seem to work well, and are cheap, but the shortest time interval is 0.1 second. I like that they use solid state relays. These only handle 12 volt loads, but my solenoids are 12V so thats fine. I use different timers for curculating pumps - sonoffs.

https://www.amazon.com/gp/product/B01J5JSE0Y/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

As far as timing, I think 300 seconds OFF is probably too long unless you have really great hang times. The best I have been able to get is around 1 to 2 minutes at most of an almost reasonably dense mist hanging around. The vast majority of your droplets will fall out pretty quick. The ones that hang around the longest will be the smallest - sub 20 micron sizes most likely - but they dont feed the roots very well. Too small a droplet size is too dry. Too big is too wet. You want the porridge just right :)

I started with 0.5 to 0.7 sec ON and a max of around 80 seconds OFF. Im almost ready to harvest and Im now at 0.9 ON x 41 seconds OFF for a little under 2 gallons/day total flow rate for my single plant - but - each setup will behave differently, so you will have to let the roots tell you what timing works best. Just dont let them dry out. They wont die if they are too wet - you just wont get fuzzy hairs.

Id recommend you try one plant in one tote for starters to get a feel for how the plant will react and what timing works best in your setup.
 

MI.BUDZ

Active Member
Right now I have the same ones as PhatNuggs in the earlier post. I also noticed Petaflora and a few others are currently running the same ones and getting it done.
I think it’s about knowing your plants just as much as anything else. People are making it happen without a masters degree in programming, electronics or physics for that matter.

Currently my total buildout and parts are less than $1000.00. Most of the parts can also be used in a F&D hybrid, NFT hybrid or other applications. After researching so many of Atomizer’s posts I had to give it a shot... Most importantly the room build can be used for any application. Sealed, filtered, fresh water, RO can be easily added, DTW discharge with pump and I already have a whole house backup generator.

Now that we are Rec Legal here in Michigan, endless possibilities:bigjoint:

I really appreciate everyone’s input and guidance.

Thanks
 
Last edited:

Larry3215

Well-Known Member
If you look closely, you can see that PhatNuggs roots have no fuzzy hairs. His roots look ok for regular hydro roots - but there are no fuzzy hairs. Also, Ive never seen any fuzzy root pics from Petflora either after much searching and asking him directly - has he posted some recently I missed?

Thats not to say he and Phatnuggs are doing anything wrong. Regular hydro roots are perfectly fine roots, but you can get them a lot cheaper and easier by going with LPA instead of HPA. Phatnugs setup is really LPA even if he is using HPA nozzles. The low pressure just wont make droplets that are small enough to get fuzzy hairs - no matter what nozzle.

Still, like I said before, I have only been playing with HPA for a few months. I spent almost three of those months early on killing off clones and seedlings getting the system mostly dialed in, and am just now finishing my first full grow. So Im no long time expert.

Still, I do have a huge root ball with fuzzy roots and not many folks can say that :)

Good luck and keep us posted on your progress. There arent enough HPA people out there - no matter the details, so we need every one we can get :)
 

Larry3215

Well-Known Member
You dont need a masters in physics, programming etc, but you DO need to create the correct environment in your root chamber or you will NOT get fuzzy roots. It sounds like you have read most of Atomizers posts. So far I have found pretty much everything he has posted to be spot on.

Getting fuzzy roots is not easy. I can tell you from experience that there are many ways to NOT get fuzzy hairs and/or to kill tham off if you do get some. In no particular order...

1) Over watering. Roots that are too wet (too large a droplet size or too long a mist cycle, or too short a dry cycle, etc) stay smooth and grow towards the bottom of the chamber very quickly. Fuzzy roots that get too wet loose the hairs and turn smooth and grow down to the bottom.
2) Air leaks or light leaks are bad for fuzzies and smooth roots, but especially fuzzies. Fuzzy roots air prune much faster than smooth roots.
3) Algae kills the fine hairs first and slows all the roots down, Algae sucks.
4) Algae killers like chlorine, copper, etc, if they are strong enough to kill the algae, also kill the fuzzies. Algae sucks big time.
5) Too long a dry cycle also kills fuzzies faster than smooth roots.

My root chamber is so full of roots now that the nozzles are all spraying directly into and on the roots big time. Ive been loosing more and more fuzzies as the chamber over fills as a result.

But - thats just my experience. I hope you have better luck!
 

MI.BUDZ

Active Member
Here is where I was initially heading. Not a lot of super fine fuzzies but he was able to get them started at one point. My chamber would definitely drain better than this set up. My thought was to suspend air pot fabric into the chamber and let the water drip onto the floor of the chamber for air pruning. Still DTW.

The Build
I would use this set up for the HPA cloning. Really could use Phatnuggz approach but more of an HPA set up. If I don't get fuzzies here at least the root mass has developed and can be fine tuned in the SOG. The 3" net pots with hydrodon and foam collars will allow for easy transfer.

The Grow
(see post 18 for the HPA fuzzies)
You can see he later went to buckets like dstroy and others did on here. That’s why I originally was trying to maintain the 16” high factor for the depth and separate each plant. Might need to continue researching and find a wider single plant Rez while maintaining the 16”+ depth. Still would run single solenoid per Rez with 2 or more heads keeping SOG in mind. Also note he is running 140psi.

Another good thread if you haven't seen it.
dstroy grow
 
Last edited:

Larry3215

Well-Known Member
Ive seen the dstroy thread, but the other one was new. Some quick thoughts.

First - Im feeling much better about my roots now. My roots are a long ways from perfect HPA roots, but at their worst, my roots are at least as good as any of those, and the total size of my root ball puts them to shame. I have a 48 gallon root chamber thats is at least 2/3 full of roots - at least. Thanks for posting those. I feel much better now :)

In that grow thread, if you look closely, you will see that his fuzzy roots are only up hi on the sides of the net pots. Thats the only place out of the direct stream from the misters. The rest of his roots are plain hydro roots because they are getting and staying too wet. Plus he is running waaaaaay too long an ON time = 10 seconds. Remember Atomizer says you only want to run the misters long enough to fill the chamber with micro droplets - no longer. Also, I would not want to run DTW with a setup like that. The over all flow rate would bankrupt you on nute costs, and you would be re-filling the rez every other day. Also note that he changed from a tote to taller buckets. Totes are too short to work well, but buckets are too narrow.

Dstroys roots are not any better as far as fuzzy hairs and for the same reasons - too small a chamber, direct spraying on the roots and too long an ON time.

Your root chamber needs to be much bigger than you are currently planning - if you want lots of fuzzy roots. If roots like you see in those threads are ok, then you will be fine with your current plan.

Jeeze. I just realized Im starting to sound like a jerk. Sorry, but my roots are way better than any of those :)
 
Top