HPA Without An Accumulator

[PetFlora]

to clarify: the bag weighs roughly 6.5gms. Including a 2 second burst = ~ 9 gms., or ~ 2.5 gms per 2 seconds/2= 1.25 gps

Assuming my math is correct...

@ 1.25 gms per second X 60 seconds X 60 minutes = ~ 450 gms.

1 gram = 0.035273962 ounces

0.035 X 450= 15.75 ounces per hour

15.75/128=0.123 ounces per minute

0.123 X 60= 7.38 GPH if the pump was running constantly, but isn't the 'effective' gph based on length of pause?

What is the 'ideal' 'effective' gph or is that a factor of pod volume, and if so what is that number?

 

[Atomizer]

1ml of water weighs 1g.
6.5g in the bag...divided by 2 seconds is 3.25g per second, so you have 3.25ml/sec *60 *60 = 11,700ml/hr or 11.7 Litres/hr.
11.7 / 3.785 = 3.09 us gph , this is the real nozzle flowrate based on the amount of liquid one nozzle delivered into the bag in a known period of time (using your unique hardware)
To get the nozzle to deliver 0.97ml in one second (as per the 0.92gph spec) you`d need to set your timer for 0.3 seconds.


Edit: ok, finally sussed what you mean..your empty bag weighs 6.5g. so the bag + water = 9g...in which case, the nozzle is doing 4.5lph or 1.19 us gph.
If your nozzle is generating the correct droplet size range and providing full coverage, a 0.5second pulse setting on your cycle timer will be about right for an 18gal chamber, a 1 second pulse for a 36gal.
If 2 seconds is your shortest possible pulse (hardware limitations) you`ll need a 72gal chamber, its doubtful you`ll get the coverage from 1 nozzle.

 

[chennemann]

Atomizer I am running the same nozzle Petflora is, but with an accumaltor. I am using 30 gallon barrel with 3 nozzles pointed inward near the top. Should I have them on for ~.3-.5 seconds? If so how long of period should I have in between mist to start off with? I will be using CO2 at 1500 PPM and ~600 watts per plant. I have been using ~1-2 second range in the past with good results.

Thanks for your help and advise.

 

[PetFlora]

Glad we finally got that cleared up. Sorry for the confusion. I am running one second, but according to Sentinel, it is not 100% accurate at one second; could be a little more, could be a little less. I collected the spray for 2 seconds, as that is what I thought you said to run as a test.

What do you consider a proper pause time considering the above?

 

[Atomizer]

Timer accuracy is as variable as nozzle specs, the only way to be 100% sure is to video the entire misting pulse and use editting software to see how long the pulse was from mist start to mist stop. That will give you the actual misting pulse time (accurate to 1/100sec) for your particular timer and hardware combo.
2 seconds is likely to be as short as your pump will allow but bear in mind 2 seconds with your hardware is the maximum allowable pulse for a 72gal chamber. If your chamber is smaller than 72gal it`ll be oversaturated with 2 seconds. You`ll need either a shorter pulse (not possible) lower flow nozzle( may be possible) or fewer nozzles to compensate (not possible as you can`t go less than 1). Thats the reason why control is important with hp aero .
Assuming 72gal chamber with correct droplet size range and full coverage, the pause timing will be around 80seconds reducing to 40seconds*. You can use a shorter pulse for more variation (always remembering that 2 seconds is the max for your hardware in 72gal), but its easier to leave it alone and vary the pause to maintain the balance. *Environmental variables will have an effect on the timing.

Chen, if the flowrate is somewhere between PF`s 1.19gph and the nozzle spec flowrate of 0.92gph, the pulse time for 3 nozzles in 30gal will be approx 0.27-0.35 seconds. The pause timing as above would be a reasonable starting point.

 

[chennemann]

Would it be better if I went down to 2 nozzles? My concern is the even coverage of the mist.

 

[Atomizer]

2 would be better but not if it compromises coverage as thats worse than having too much flow. With 2 nozzles, the pulse time would increase slightly to 0.4 -0.5 seconds, pause range of 75seconds reducing to 35seconds.
Its difficult to get the coverage, flow and droplet size range all at the same time but even something as simple as a cycle timer adjustment in the right direction can make a big difference.

 

[PetFlora]

Yes, coverage trumps all. In my 17G rectangular tote, using a single head, the roots in the corners were not getting good mist. Yesterday I replaced it with a dual head and repositioned that head mid way on the long side, aiming one head left the other right.

 

[PetFlora]

Newest Pics

Lonely Girl has come a long way in 3 weeks



Current Grow responding well to shortened feed/pause cycle.

The plant in the middle is BC Mango started at the same time as the others, which were sold to me as AFs, but only 1 -10 seeds actually followed AF cycle. It is a male. I moved it outside where it hermied. It was maybe 8 seeds. Will they be more AF like?






Roots are about as good as I can expect considering for the first 2 weeks after germ that they were getting misted at 30 second intervals. Still, there are loads of tiny lateral roots developing in just the last few days.

FYI Lonely Girl's roots have not grown much since putting her in the 30 second feed system 2 weeks ago; makes me think veg stage is the most critical to proper aero root development

 

[Atomizer]

Yes, coverage trumps all. In my 17G rectangular tote, using a single head, the roots in the corners were not getting good mist. Yesterday I replaced it with a dual head and repositioned that head mid way on the long side, aiming one head left the other right.

Its a trade off, for 2 reptile nozzles in 17gal, you`ll need a maximum 0.25 second misting. Larger chambers generally need fewer nozzles as the mist patterns tend to overlap and they have more space to fully develop. Run a nozzle outside the chamber and see what the coverage is like compared to inside.

 

[PetFlora]

I have a 30G tote that I plan to convert this weekend. Still trying to figure out best position for max of 6 plants. I have 5 growing now, but no idea if any will be males. I am thinking basically to space them in thirds, but place 4 plants in the corners closer to the middle so mist can wrap around the corners. I will try a single head on the short side: if that doesn't work then a dual head mid way on the long side. This is eazy peezy to do with the heads I source from Reptile Basics

hth

 

[PetFlora]

I think I heard my plants say 'Thank You" after moving them into the 30G pod. I have to use a dual head; even with it, if I don't have them properly aimed left and right, one of the plants wilts.

Also, it is 89 degrees here today. The room they are in is open beam ceiling- no attic or insulation to reflect the heat. When I run the ac it doesn't counter the heat. This means the inside of the pod gets hot. I drilled a hole on the short side in case I decided to place the dual head there. The hole is near the recirculating fan, so I repositioned the fan to blow some air into the pod, but realized I needed to drill some holes in the opposite side (up high) for the heat/humidity to escape.

Pausing for 35-40 seconds. Is that good for a 30G pod? Is there a formula for pause vs volume?

hth

 

[Atomizer]

With 2 of your nozzles you`d need no more than 0.4 seconds of mist for 30gals. If you can only manage 1 second you`ll be overmisting (wet/dry cycles). The best compromise there is to use a pause timing range of 3mins reducing to 1.5mins.
If your droplet size is also too large then all bets are off as you won`t be meeting any of the criteria needed for hp aero.

 

[PetFlora]

I kind of got lost in your wet/dry timing explanation. Are you saying...

1 second wet > 1.5 minute dry
2 second wet > 3.0 minute dry

If yes, are these times based on a 30G pod?

Also, wouldn't ambient temps (like 90 degrees yesterday) and/or lamp heat beating down on the surface of the pod play a role in length of dry period?

 

[Atomizer]

I kind of got lost in your wet/dry timing explanation. Are you saying...

1 second wet > 1.5 minute dry
2 second wet > 3.0 minute dry

If yes, are these times based on a 30G pod?

Also, wouldn't ambient temps (like 90 degrees yesterday) and/or lamp heat beating down on the surface of the pod play a role in length of dry period?

If the misting is too long they will get wet. The flowrate and number of nozzles dictates the maximum misting duration for the chamber size. The pause duration controls the amount of liquid going through the chamber per day in bitesize chunks. During early growth you don`t need as much throughput as in late flower. If your ambient is 90F you need better environmental control and/or chamber insulation. The suggested timings are a compromise brought about by the hardware limitations, if you could achieve the 0.4second misting the pause timing range would be shorter.

 

[PetFlora]

I am having difficulty keeping all 4 plants wet in the 30G pod, even with dual heads and 2 second wet cycles. Still working at adjusting the left head to reach the plant in the far left corner, which has the least amount of root mass to collect nutes and feed the plant.

The 30 second wet times caused long roots to develop in less than 2 weeks, instead of a nice ball of roots up high close to the plants. While the vertical roots have some lateral roots and hairs, the majority of the lateral roots are close to and on the bottom. It's a long way for nutes to climb to feed the plant.

Hopefully this one will rebound, or be a male so I can pull it.

hth

 

[PetFlora]

Eureka- Root Hairs!

A is right again. 2 days after moving plants from 17G pod to 30G pod I am seeing root hairs developing on the vertical roots. The problem was a combination of a pod too small and a mist cycle too long (even at one second): doubling the volume did the trick.

W/D is 1sec/55 seconds. Due to the high ambient room temp I do have some condensation on the sides. I will look into wrapping pod with insulating foam, or wrapping with some windscreen reflectors that I have on hand

hth

 

[Atomizer]

If you can increase the chamber volume to 70gal and maintain full coverage with the 2 nozzles and your current pulse timing you`ll be about there

 

[PetFlora]

Atomizer: As I was still having coverage issues (including mist hang time), I went back and read where you suggested the pump might be losing pressure, which could make for larger droplets. Thinking about that in general, it occurred to me to check the screens in the heads; both were slightly clogged. Then I checked my inline 200 mesh filter, it too had some precip. My rez is clean so this was probably a carry over from a week or so ago, when I dumped and cleaned it, but overlooked cleaning the filters. Now I may be able to replace the dual head with a single head. I say may as I think I would need an accumulator to get the initial push through a single head to optimally fill the 30G pod. Stay tuned

70G huh? Now that would be a HUGE pod.

 

[PetFlora]

I cannot find the thread where this was posted. Anybody know who wrote this? I would like to communicate with him

"There are mainly two types that are based on former and newer scientific results.
1. about 180 N versus 220 P, is the more recommended formula for a hot, tropical or not fully climate controlled and rather warm indoor climate (high light heat output).

2. 220 N versus 180K (could vary but for the sake of simplicity, I'll just reverse it, as it is damn close) for a cooler climate or if you prefer, growing conditions clearly under 20-25° C."