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sansa

Registered: 11/17/09
Posts: 647
Last seen: 10 years, 4 months
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Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2?
#11733868 - 12/28/09 07:54 PM (15 years, 23 days ago) |
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At STP:
water vapor=22.414 L/mol (least dense) O2=22.393 L/mol CO2=22.262 L/mol (most dense)
That would mean holes on the bottom of the FC are very important for discharging CO2 but holes above the perlite on the sides should probably be filled with polyfill to keep the water vapor in and holes on the lid of the FC might not be a good idea because the water vapor will escape from the top.
I'm thinking below the perlite level have regular small unfilled shotgun type holes for CO2 exchange. Above the perlite level should be monotub style 2" holes with polyfill. The lid should probably have no holes. The put the whole thing up on risers so the CO2 drops out the bottom.
I've got two tubs that're in that config right now which seem to be keeping the RH up nicely. I'm wondering if maybe that's a mistake in the tutorials that say to drill holes in the lid?
Edited by sansa (12/28/09 07:55 PM)
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feelfunny
I am you




Registered: 03/11/09
Posts: 8,747
Loc: South
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11733891 - 12/28/09 07:57 PM (15 years, 23 days ago) |
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depends on what kind of FC you are doing. i wouldnt put holes in the top of my mono eather but would not go without on my SG FC
-------------------- IF A CAT AND DOG CAN GET ALONG WHY CANT EVERYONE ELSE?
If the sky is falling, don't look up!
Feel Family Founder. me if you are tired of hearing, "Use the search function".
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sansa

Registered: 11/17/09
Posts: 647
Last seen: 10 years, 4 months
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: feelfunny]
#11733908 - 12/28/09 08:01 PM (15 years, 23 days ago) |
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Quote:
feelfunny said: depends on what kind of FC you are doing. i wouldnt put holes in the top of my mono eather but would not go without on my SG FC
Why does it make a difference? The density of H2O vapor is the same in either case.
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curbstop
Regnarts


Registered: 06/02/09
Posts: 810
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: feelfunny]
#11733917 - 12/28/09 08:02 PM (15 years, 23 days ago) |
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Quote:
I'm wondering if maybe that's a mistake in the tutorials that say to drill holes in the lid?
I could go on with the whole positive pressure to negative pressure and how exactly the science behind it all works,But I won't
I will however say that 10,000 SG done with 6 sided hole's that produce day after day is no mistake 
-------------------- is multispore a spore company
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sansa

Registered: 11/17/09
Posts: 647
Last seen: 10 years, 4 months
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: curbstop]
#11733938 - 12/28/09 08:05 PM (15 years, 23 days ago) |
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Quote:
curbstop said:
Quote:
I'm wondering if maybe that's a mistake in the tutorials that say to drill holes in the lid?
I could go on with the whole positive pressure to negative pressure and how exactly the science behind it all works,But I won't
I will however say that 10,000 SG done with 6 sided hole's that produce day after day is no mistake  
Uh, OK. Why did you bother to post that?
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DanKnugget
Mysterious Traveller



Registered: 07/15/03
Posts: 1,074
Loc: On a boat
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: curbstop]
#11733942 - 12/28/09 08:07 PM (15 years, 23 days ago) |
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just search rr's name on shotgun tek, he has explained in detail more than once...
-------------------- My 3 proverbs:
1. School is for people who don't know stuff.
2. Jobs are for losers.
3. Reading is for people with nothing better to do.
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curbstop
Regnarts


Registered: 06/02/09
Posts: 810
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11733962 - 12/28/09 08:09 PM (15 years, 22 days ago) |
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Do a simple search with Shotgun and rogerrabbit name in the posted by category.
You will then see why I posted that,,,The reason is comon sense,,RR repeatedly explains why over and over and over. Why do i need to go into detail on why when you are quite capable of searching out the answer yourself.
-------------------- is multispore a spore company
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jimbotron
Patty-Cake Enthusiast



Registered: 02/24/09
Posts: 2,324
Last seen: 11 years, 1 month
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11734189 - 12/28/09 09:01 PM (15 years, 22 days ago) |
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If you're going to argue something completely counterintuitive (ever seen fog?) based on a single number off a chart, don't get all snippy about it.
-------------------- BEST TEAM IN THE UNIVERSE
 
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wygram
Myconaut

Registered: 01/28/07
Posts: 573
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11734199 - 12/28/09 09:04 PM (15 years, 22 days ago) |
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Quote:
sansa said: water vapor=22.414 L/mol (least dense) O2=22.393 L/mol CO2=22.262 L/mol (most dense)
Look at those differences. They are insignificant for an environment where you have constant fresh air flow, so the CO2 layer as exactly as those numbers seem to suggest.
That being said, the holes in the bottom aren't for the sole purpose of releasing CO2. The holes allow fresh air to enter from the bottom, pick up moisture and rise to the top of the fruiting chamber, and exit out the top. This means humidity is not increased by reducing air flow, but in fact it is decreased.
-------------------- Changing your mind is one of the best ways of finding out whether or not you still have one.
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sansa

Registered: 11/17/09
Posts: 647
Last seen: 10 years, 4 months
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: wygram]
#11734323 - 12/28/09 09:28 PM (15 years, 22 days ago) |
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Quote:
wygram said:The holes allow fresh air to enter from the bottom, pick up moisture and rise to the top of the fruiting chamber, and exit out the top.
Why would you want the water vapor to exit out the top?
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feelfunny
I am you




Registered: 03/11/09
Posts: 8,747
Loc: South
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11734340 - 12/28/09 09:31 PM (15 years, 22 days ago) |
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why would you want old water to stay in?
-------------------- IF A CAT AND DOG CAN GET ALONG WHY CANT EVERYONE ELSE?
If the sky is falling, don't look up!
Feel Family Founder. me if you are tired of hearing, "Use the search function".
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Thyrax
No way



Registered: 01/03/08
Posts: 1,068
Loc: Montreal, Quebec
Last seen: 14 years, 4 months
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11734660 - 12/28/09 10:36 PM (15 years, 22 days ago) |
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air circulation from botom to top bringing up moisture from perlite is the main concept of the SG thats why it have a great FAE rate, that wouldnt be that much effective than without hole on the top cus it wouldnt evacuate, and would suck much less aire from the botom witch would make less moisture from the perlite coming up wich would lead to poor result. What can I say more dude ?
--------------------
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Thyrax
No way



Registered: 01/03/08
Posts: 1,068
Loc: Montreal, Quebec
Last seen: 14 years, 4 months
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11734673 - 12/28/09 10:39 PM (15 years, 22 days ago) |
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Quote:
sansa said: At STP:
water vapor=22.414 L/mol (least dense) O2=22.393 L/mol CO2=22.262 L/mol (most dense)
That would mean holes on the bottom of the FC are very important for discharging CO2 but holes above the perlite on the sides should probably be filled with polyfill to keep the water vapor in and holes on the lid of the FC might not be a good idea because the water vapor will escape from the top.
I'm thinking below the perlite level have regular small unfilled shotgun type holes for CO2 exchange. Above the perlite level should be monotub style 2" holes with polyfill. The lid should probably have no holes. The put the whole thing up on risers so the CO2 drops out the bottom.
I've got two tubs that're in that config right now which seem to be keeping the RH up nicely. I'm wondering if maybe that's a mistake in the tutorials that say to drill holes in the lid?
and yeah btw, of course the tub with less hole will hold more moisture. But the co2 will build up more too. IM pretty sure your tub does not have as much as FAE than a shotgun.
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feelfunny
I am you




Registered: 03/11/09
Posts: 8,747
Loc: South
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: Thyrax]
#11734703 - 12/28/09 10:45 PM (15 years, 22 days ago) |
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i agree
-------------------- IF A CAT AND DOG CAN GET ALONG WHY CANT EVERYONE ELSE?
If the sky is falling, don't look up!
Feel Family Founder. me if you are tired of hearing, "Use the search function".
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pblcenmy1
str8 noob



Registered: 11/24/09
Posts: 221
Loc: Colo. Rockies
Last seen: 8 years, 11 days
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: Thyrax]
#11734754 - 12/28/09 10:51 PM (15 years, 22 days ago) |
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So many variables effect humidity, airflow, FAE,.
Its the wet air mixing with dry air that recreates earths own cycles.
The questions arnt why? the answers are how? And given size, shape and volume, all account for all variables.
Just mimic natural cycles and the mushroom wont have an opinion.
-------------------- ~LoveLife~
Down 2 Earth, Up N Space!
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RogerRabbit
Bans for Pleasure



Registered: 03/26/03
Posts: 42,214
Loc: Seattle
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: sansa]
#11734824 - 12/28/09 11:03 PM (15 years, 22 days ago) |
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It's not just about the specific gravity of moisture vs air and CO2. The air in a properly functioning terrarium is never still. By moving, it mixes. There's not a nice neat layer of CO2 on the bottom waiting to drain out. That's not how it works. In fact, most of the CO2 exits through the holes in the top.
Remember, the heat of the cakes, however slight causes convection. During the day when a light is on, there is a slight heating. When air passes through the perlite, there's an evaporative cooling effect. All of this works together in a shotgun terrarium to provide a turbulent environment with fresh air constantly circulating for the mushrooms.
It's also common for new growers to overestimate the importance of humidity. We want a high humidity of course, but just as important, we also want lots of fresh air, which is the number 1 pinning trigger. The perlite provides the moisture for humidity, the holes provide the fresh air, and misting replenishes the moisture that evaporates from the cakes. Try to add to one of those three factors at the expense of the other two, and performance drops. RR
-------------------- Download Let's Grow Mushrooms
semper in excretia sumus solim profundum variat
"I've never had a failed experiment. I've only discovered 10,000 methods which do not work."
Thomas Edison
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DanKnugget
Mysterious Traveller



Registered: 07/15/03
Posts: 1,074
Loc: On a boat
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: RogerRabbit]
#11734867 - 12/28/09 11:09 PM (15 years, 22 days ago) |
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Can you grow mushrooms that need high FAE like oysters in a shotgun, or would you need a small computer fan or something underneath to give more FAE?
-------------------- My 3 proverbs:
1. School is for people who don't know stuff.
2. Jobs are for losers.
3. Reading is for people with nothing better to do.
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sacredcow
Stranger
Registered: 08/01/09
Posts: 64
Loc: TN
Last seen: 13 years, 11 months
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Re: Holes on top of shotgun a bad idea because water vapor is less dense than O2 and CO2? [Re: DanKnugget]
#11734891 - 12/28/09 11:13 PM (15 years, 22 days ago) |
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particle diffusion in moving air is great enough to overcome the inertia that you think might arise from the density of these gasses
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