night time humidity

[attila76]

Hi all Icmag,

See... I got this friend who started a sealed container grow, and he wanted me to post this thread.
About the system: 8k, fully sealed 40' container, co2 supplemented w/ppm3 @ (1400ppm) , 2 x 2k btu mini split a/c, temps range 63-85 w/ 72 average, one humidifier set to run at 60%.



http://www.icmag.com/ic/photo_popup...&prod=albums&ins=link_thumb_2_orig&alb=20506#

http://www.icmag.com/ic/photo_popup...&prod=albums&ins=link_thumb_2_orig&alb=20506#

Ok some background: He says that at night the humidity climbs up to the 90-98% range. Whilst in the day it is 40-60% range. Here is why: When the lights are on the a/c units are on. And the a/c acts as a powerful dehumidifier. So when the lights go out the a/c stops cooling & dehumidifying. Therefore the humidity rises. So far no ill effects have been noticed. Also I do not have PM or any mold issues. And as this place is sealed I do not expect to bring it in thru the air ducting or clones.

In the daytime when photosynthesis and carbon uptake occur high humidity causes the stomata to close, thereby stopping or slowing carbon uptake and growth. At night time this process does not occur. Still the plant does exchange gases at night. ...

It is at this point that my knowledge breaks down.

Here is the question: Is this night time humidity a problem?

 

[attila76]

Oh ya,

Obviously, getting more dehumidifiers would solve the "problem." But perhaps its not a problem.
Only sayin... or so I heard from a friend..

 

[Rocky Mtn Squid]

90-98% humidity is an invitation for bud rot and mould to develop, especially when your plants get big and fat with buds. Moreover, high humidty will create lots of condensation in your room. Electrical component's do not take kindly to having water on them. Tell your "friend" that he needs to remedy this situation asap.

 

[mikeross]

buy a santa fe classic dehumidifier. Its like running 3 kenmorre 75pints for the same power... very efficent for what it does.

If that doesnt work which I think it should buy another one... they sell for about 1000 each but they are the best dehumidifier for med-large ops imo

good luck

 

[jammie]

buy a santa fe classic dehumidifier. Its like running 3 kenmorre 75pints for the same power... very efficent for what it does.

If that doesnt work which I think it should buy another one... they sell for about 1000 each but they are the best dehumidifier for med-large ops imo

good luck

spot on! i had a santafe before i had a basement grow and they can pull about4-5 gals every 12 hours. oh by the way- that water is better than RO. 0 ppms, ph5.6 and stable as it gets. i use it exclusively in my dwc system.

 

[mule420]

We have a strain of PM in Colorado that is nasty! We don't have the humidity here so when we do make it humid that stuff grows like wildfire. Just walking across a lawn with PM and then into the grow room without changing clothes and it's over... If I was him I would be running a sulfur burner pronto not in flower! To avoid any mold or PM issues... And getting a big dehumidifier! Peace and puffs

 

[attila76]

Thanks G's,
good advice all around.

Ya, now that I got my system properly sealed nighttime humidity has becoming a problem waiting to happen. But shite, the sante fe dehumi is 1,400 clams! my friend says thats a hefty chunk of change. I'm beginning to realize that I need a much larger dehumidification setup then a I originally thought. Shite, I haven't budgeted for that.

If I set up a nighttime intake to bring in dry air, some nights it will get too cold. Argg..

Anyone aware of a dehuey that's a little easier on the wallet?

 

[caljim]

Sounds like it time for big boy toys. At 8k, one run should easily absorb the cost of the santa fe

Takes money to,.....well ya know what I mean

 

[ganjaments]

So what are the ideal, and maximum night time humidity's?

 

[1DankBasement]

Jammie, you said you prefer the water that your dehumidifier accumulates? I have thought about just watering with it before but always end up dumping it out cause I don't know if it is safe... Also I have been trying to cut down on heat lately, think its worth dropping from 86 degrees to 78- If my humidity climbs from 48 to 61? I have a surplus of air movement so I'm hoping mold is out of the question.

 

[what the]

The water coming off your dehum or a/c is nearly distilled water. It will pick up contaminants such as copper from the coils and CO2 from the air.
Unfortunately you lose all the hardness. While this sounds good, it isn't. It reduces the buffering capacity of your water. You're better off using tap water and draining to waste. It probably won't hurt your plants, but it won't help any either.

 

[ganjaments]

The water coming off your dehum... lose all the hardness. While this sounds good, it isn't. It reduces the buffering capacity of your water. You're better off using tap water and draining to waste. It probably won't hurt your plants, but it won't help any either.

By this logic, RO water is garbage also?

 

[SGMeds]

The Sante Fe's are the bomb. Check out their sister brand... phoenix... bad-ass durable + w wheels + pump. Can use w a controller.




You could also open vent w an 8" fan tied to a scrubber... exchange the air volume of the cab out quickly after the lights go out.

In addition, get an electrical space heater to raise the temps... lowering the RH.



Either way, going to need to make the investment. Look at the cost of losing 25%+ of your yield and having shit infested product... sell yourself at the local bus station if you have to. ;-)

 

[mule420]

spot on! i had a santafe before i had a basement grow and they can pull about4-5 gals every 12 hours. oh by the way- that water is better than RO. 0 ppms, ph5.6 and stable as it gets. i use it exclusively in my dwc system.

Jammie, you said you prefer the water that your dehumidifier accumulates? I have thought about just watering with it before but always end up dumping it out cause I don't know if it is safe... Also I have been trying to cut down on heat lately, think its worth dropping from 86 degrees to 78- If my humidity climbs from 48 to 61? I have a surplus of air movement so I'm hoping mold is out of the question.

The water coming off your dehum or a/c is nearly distilled water. It will pick up contaminants such as copper from the coils and CO2 from the air.
Unfortunately you lose all the hardness. While this sounds good, it isn't. It reduces the buffering capacity of your water. You're better off using tap water and draining to waste. It probably won't hurt your plants, but it won't help any either.

Not all water out of those machines is usable! Mine is like 140 ppm no EC sorry... And it's like 4.2 on PH... And smells slightly of chemicals... So I wont be using it for now, maybe I need to pop a bag seed and give it a go and do a grow report on how it works out??? NOTE my unit is NOT a santa fe the water might be good out of one of those...



And to expand on what SGmeds said... You can get a cheap propane ventless space heater to run at night. PM loves the cold wet of the night so put one in there and flip it on 60*F and as a added benny you got CO2 for free... Notice however the byproduct of a ventless heater is water so you still need a dehuey... Unless you use a electric space heater then that will take out the humidity... Peace and puffs

 

[sparkjumper]

I run a sealed room also you should,nt kill you AC during dark hours it should always be left on.

 

[what the]

By this logic, RO water is garbage also?

No, not at all. I think maybe you need to learn a little water chemistry and how RO is different from distilled water.

However... in many instances people would be better off, or no worse with the city water compared to RO water. Some people need it, most don't

 

[ganjaments]

I think maybe you need to learn a little water chemistry and how RO is different from distilled water.

I honestly don't have time to teach myself chemistry. Maybe you could explain a little here what the difference is?

 

[what the]

Water hardness gets very complicated, very quickly.

Essentially RO does little to change the water's Ca hardness. You want some hardness as it acts as a pH buffer. Distilled water is sucking water gas from the air and condensing it, no hardness. (I know, not exactly worded perfect for those who understand how this works, but it's easiest to explain in a couple sentences this way)
Distilled water is actually making it harder to keep your pH where you want it, RO does not. But, in many cases city water is very good, RO water will filter some minerals out that are beneficial to your plants. So in many cases it is doing nothing or actually hurting. Although it certainly won't do any damage to your plants. The difference isn't that much. Distilled water on the other hand will make it noticeably more difficult to maintain pH.

 

[ganjaments]

Distilled water on the other hand will make it noticeably more difficult to maintain pH.

I've definitely noticed this. However I'm still confused. Isn't hardness related to mineral content? Are you saying there are still minerals present in 0ppm RO water?

 

[what the]

Are you saying there are still minerals present in 0ppm RO water?

yes. More than in distilled water. They both are removing salts and minerals. The RO leaves more (typically). A little does a lot. So you won't see this as much as in distilled water which is typically very pure. (the stuff in bottles, not necessarily that coming off your copper dehum coils.) A difference in only 50 ppm in Ca hardness can make a big difference in the pH buffering capacity. I really don't trust most EC meters at levels this low. A 0ppm reading may be quite a bit off.
Off the top of my head I'd say any water under 150 ppm is fine as it is assuming no unusual pollutants. City water in the US is typically very clean and well adjusted. Great for hydro systems. Typically is the key word. There are some people that absolutely need to run their water through an RO.
I guess the main thing to remember is some of the minerals present you want in your solution. They're not all bad.