Low Pressure Aero build...it has begun!

[diggs99]

Here they are the next morning after moving into the veg box and net cups. Roots already poking out through the cups.

I did change the timer to 1/20 as after 15mins I was still seeing lots of water on the roots and cups. As I’ve said before, gonna be lots of trial and error before I get it all figured out lol


also a couple bonus pics during transplant.

 

[Keesje]

I did change the timer to 1/20 as after 15mins I was still seeing lots of water on the roots and cups. As I’ve said before, gonna be lots of trial and error before I get it all figured out lol

Why would it matter if there is still lots of water om the roots and cups?
Or do you look at it from a 'less energy consumption' point of view?

 

[diggs99]

Why would it matter if there is still lots of water om the roots and cups?
Or do you look at it from a 'less energy consumption' point of view?

i honestly dont know why it would matter lol....it probably dosent

My idea is always less is more, so if they are staying saturated at 15mins, maybe they will also be wet at 20....25....30mins? Is there a benefit to running pumps/spraying more frequently? If there is, ill try that out haha

This being my first time, i really dont know what im doing, just tinkering with things until i get an idea lol

 

[Keesje]

I don't have a straight answer to that, but will give you some thoughts.

* Roots can only absorb oxygen when they are wet or damp. So totally dry roots can not absorb oxygen anymore. This does not mean that the plant dies immediately, because there are some reserves in the plant. So, for that reason, keep your roots moist.
* An electrical or mechanical pump will always heat up the water. It can be just a little bit, but it will happen. If there is a temperature you want to maintain, that is something to consider. If your res is on a really cold floor, the heat of a pump can even be beneficial. But if your water becomes too warm, longer pump intervals could help.
* There are studies that show that the more times during a day the roots gets new water + nutrients, the better the yield (it was not a test on cannabis) So more floodings with short intervals > higher yield. The researchers thought that it had to do with the fact that water + nutrients + oxygen are available almost all the time. No overwatering, no overfeeding, no under-oxygenation. Everything is there for the roots when they need it.

Personally I think it will not matter that much in your case. Hahaha.
I mean every 15 or 20 minutes... not much of a difference. There will still be enough water + nutrients around the roots after 20 minutes. Probably also after 30 minutes. 2 hours without any medium is something else.
I was just really curious what made you decide that.

 

[gr865]

Run my DIY EZ Cloner at 20 sec off/10 sec on.
First run got 34 out of 34 rooted and transplanted.
Have not had any success with clones from this grow, got small roots on a couple of clones but the plants just wilted and died.
Not sure WTF is up with this.

 

[boybelue]

If you can run your pumps 24/7 without temp issues, in my experience its better. I think it keeps things more aerated.

 

[diggs99]

I don't have a straight answer to that, but will give you some thoughts.

* Roots can only absorb oxygen when they are wet or damp. So totally dry roots can not absorb oxygen anymore. This does not mean that the plant dies immediately, because there are some reserves in the plant. So, for that reason, keep your roots moist.
* An electrical or mechanical pump will always heat up the water. It can be just a little bit, but it will happen. If there is a temperature you want to maintain, that is something to consider. If your res is on a really cold floor, the heat of a pump can even be beneficial. But if your water becomes too warm, longer pump intervals could help.
* There are studies that show that the more times during a day the roots gets new water + nutrients, the better the yield (it was not a test on cannabis) So more floodings with short intervals > higher yield. The researchers thought that it had to do with the fact that water + nutrients + oxygen are available almost all the time. No overwatering, no overfeeding, no under-oxygenation. Everything is there for the roots when they need it.

Personally I think it will not matter that much in your case. Hahaha.
I mean every 15 or 20 minutes... not much of a difference. There will still be enough water + nutrients around the roots after 20 minutes. Probably also after 30 minutes. 2 hours without any medium is something else.
I was just really curious what made you decide that.

Ya this all makes perfect sense, im probably just overthinking things, i do that from time to time lol

I can run the pump 1on / 7 or 8 off and keep temps in the 69-70f range in the cooler. So maybe i was looking at things in reverse, rather than increase off time, i can decrease it and spray more often.



I tried 1/5 and temps shot up to 75-76.....24/7 and it gets hot quick.

 

[diggs99]

Run my DIY EZ Cloner at 20 sec off/10 sec on.
First run got 34 out of 34 rooted and transplanted.
Have not had any success with clones from this grow, got small roots on a couple of clones but the plants just wilted and died.
Not sure WTF is up with this.

Ya i ran my cloner 1min on and 15 off, had very good success.


Ive seen so many variations of times, im starting to think it dont matter lol

 

[Keesje]

If you can run your pumps 24/7 without temp issues, in my experience its better. I think it keeps things more aerated.

I think with sprayers it does not work like this.
The moment the sprayers stop, the wet roots are surrounded by oxygen in gaseous state. How much more aerated do you want it to be?
The oxygen in the air hits the water around the roots, turns into DO and can be absorbed by the roots. Plenty of oxygen around the roots.

 

[boybelue]

I think with sprayers it does not work like this.
The moment the sprayers stop, the wet roots are surrounded by oxygen in gaseous state. How much more aerated do you want it to be?
The oxygen in the air hits the water around the roots, turns into DO and can be absorbed by the roots. Plenty of oxygen around the roots.

There has to be surface tension to aerate the solution. A small coating of water over the roots, whether it be only a few thousandths will not become aerated by contact with oxygen.

 

[Keesje]

There has to be surface tension to aerate the solution. A small coating of water over the roots, whether it be only a few thousandths will not become aerated by contact with oxygen.

How do roots in soil get oxygen then?

And oxygen does get in the water by any contact with water. The most efficient way is on the surface of water when this is agitated.
But even with bubbles in water there will be an exchange between the water and the oxygen in the bubbles. Very inefficient, but it will happen.
When roots are damp and surrounded by air, there is air pressure. The air pressure will 'push' the O2 into the water.
And because there are so many mg of O2 in air, there will be plenty of it.

Or did I misunderstand what you meant?

 

[boybelue]

How do roots in soil get oxygen then?

And oxygen does get in the water by any contact with water. The most efficient way is on the surface of water when this is agitated.
But even with bubbles in water there will be an exchange between the water and the oxygen in the bubbles. Very inefficient, but it will happen.
When roots are damp and surrounded by air, there is air pressure. The air pressure will 'push' the O2 into the water.
And because there are so many mg of O2 in air, there will be plenty of it.

Or did I misunderstand what you meant?

Im talking about supersaturation not just the equilibrium from atmospheric pressure. It takes agitation to reach supersaturation. Water continuously on the move can reach supersaturation, but those down times when the pump is off the saturation will equalize out back to equilibrium. I use to know more about this but my mind/memory is rusty but you can look into Henry's law and itll be accurate and wayyyy more factual than my tired ole mind! Lol

 

[Keesje]

Thanks for the explanation.

I will comment a bit (because this is a forum and info might help others)
The basics of Low Pressure Hydroponics and High Pressure Hydroponics is that you give relatively short burst of water to your roots.
This helps save water and provides lots of oxygen. (just 2 of the benefits)

It might be that supersaturation will be easier reached by water continuously on the move.
I know too little about supersaturation.
What I can say is that supersaturation is not needed with hydro. Not with DWC, HPA, LPA, RDWC, Waterfall, E&F, flooming, whatever.

Roots can only absorb a certain amount of O2 per day. (around 200 mg per hour per kilo of roots is very average)
With roots being damp and in touch with air, there is plenty of O2.
All this O2 will hit the water > it will get absorbed by the water > because - as you said - this is Henry's Law. There is always an exchange between liquids and gasses. At a certain moment the exchange will stop when the equilibrium is reached.
But when the roots start absorbing this DO (that got there because of Henry's Law), there will be an imbalance again. At that moment the water will absorb fresh O2 again. The whole cycle starts over. And over, and over. As long as the roots want oxygen, there is an endless amount of O2.

With HPA and LPA the damp roots are surrounded by O2 in gaseous state. Ideal circumstances for the roots.

 

[boybelue]

Thanks for the explanation.

I will comment a bit (because this is a forum and info might help others)
The basics of Low Pressure Hydroponics and High Pressure Hydroponics is that you give relatively short burst of water to your roots.
This helps save water and provides lots of oxygen. (just 2 of the benefits)

It might be that supersaturation will be easier reached by water continuously on the move.
I know too little about supersaturation.
What I can say is that supersaturation is not needed with hydro. Not with DWC, HPA, LPA, RDWC, Waterfall, E&F, flooming, whatever.

Roots can only absorb a certain amount of O2 per day. (around 200 mg per hour per kilo of roots is very average)
With roots being damp and in touch with air, there is plenty of O2.
All this O2 will hit the water > it will get absorbed by the water > because - as you said - this is Henry's Law. There is always an exchange between liquids and gasses. At a certain moment the exchange will stop when the equilibrium is reached.
But when the roots start absorbing this DO (that got there because of Henry's Law), there will be an imbalance again. At that moment the water will absorb fresh O2 again. The whole cycle starts over. And over, and over. As long as the roots want oxygen, there is an endless amount of O2.

With HPA and LPA the damp roots are surrounded by O2 in gaseous state. Ideal circumstances for the roots.

Imo I believe with any method of hydro, excluding HPA, a super oxygenated solution is superior to equilibrium. Ive ran many different types of hydro and I always had better results running my pumps 24/7 as long as the temps were maintained at the proper level as warmer solutions will not hold as much DO. I built several LPA units with nft type chambers or plastic 4x4 and 5x5 fence post covers. I played around with timers at different on/off times and had CAP timers that came preset to 1min on 4min off. I tried 3 different pumps. In the end my plants responded best to a 24/7 feed cycle and a 1200gph pump which was the largest with the others being 800gph and 1000gph. This was just my experience, others may be different.

 

[diggs99]

Here are pics from day 3 in the veg box

almost got the big system finished, should be testing it this morning hopefully .

 

[icetech]

Here are pics from day 3 in the veg box

almost got the big system finished, should be testing it this morning hopefully .

Those look perfect.

 

[myke]

Curious why you made a veg system. Could you have not left them in the cloner?

 

[diggs99]

Those look perfect.

Thanks man

Curious why you made a veg system. Could you have not left them in the cloner?

The red cooler is quite a bit smaller in height plus it only has the 2" neoprene collars for plant sites, i wanted to move the clones into net cups so they could easily be transferred to the bigger totes when they were ready.

If i had left them in the cloner, i wouldnt have gotten them back out of the holes without damaging roots

 

[icetech]

Just read through this whole thread, LPA looks fun but i don't think i'll ever switch.. i'm too cheap to start again BUT... i am definitely making a aerocloner.. i suck bad at cloning and those roots look amazing.

 

[diggs99]

Just read through this whole thread, LPA looks fun but i don't think i'll ever switch.. i'm too cheap to start again BUT... i am definitely making a aerocloner.. i suck bad at cloning and those roots look amazing.

Ya man, you wont be disappointed, they are fairly cheap to build too.

cheap misters from amazon
cheap pump from amazon
piece of pvc and couple fittings
cheap tote/cooler/bucker
Neoprene collars.

Thats everything i used.