My room defies the laws of ventilation please help

[BattleAxe]

Greetings all uh yall
Here is the deal. I share a minisplit between my veg and bloom rooms. Split is in bloom, I have a passive intake that consists of 2x8" holes low in the corner of bloom passively allowing air into veg and an active, 8" 747 CFM exhaust fan that pulls air out of veg back into bloom. Currently there is a 9 degree drop between bloom 69 and veg 78. I just added the second hole, before this I had an active intake and matching exhaust but this was creating positive pressure in my veg and co2 was escaping the space not to be recirculated.

Now with the passive intake, I have neg pressure but the veg isn't being cooled properly. I thought that with the addition of the hole, I would be able to pull more air through the veg, after cutting the first hole and not seeing results, I opened the door thereby creating a huge passive intake and only was able to cool the room to within 5 degrees. Bloom 70 veg 75. This is obviously better than nothing but I can't run the room like that while flowering and still confused as to why the temps dont match closer. Theoretically speaking, I should be able to pull more air through veg with a bigger intake and cool room to lower temp. Intakes dont get bigger than a door so WTF?

Here are some pics to help you envision my disaster.

Any help is greatly appreciated, I originally posted this in the thread in my sig but haven't gotten much help. Any input is greatly appreciated.




And some root porn for all you pervs.

 

[BattleAxe]

bump, nobody has anything to offer? Where are the ventilation experts?

 

[Dislexus]

Too bad you didnt get a mini-split that operates two units

So you are recirculating 747 cfm between bloom and veg, ok goddamn that should do it...

1) If you had active intake to the veg causing co2 loss, now that you have only exhaust perhaps it is now pulling warm air from where your co2 was previously leaking.

2) Perhaps if you switched your veg reflectors to air-cooled, and attached to your current exhaust, cool air gets pulled out of bloom into veg, warm air pulled through veg lights and sent back into bloom.

3) The side of the room the passive intakes are on, is it far away from the mini-split unit? You want your warm-air return from the veg coming out near the mini-split unit, and the cool-air intake to veg being pulled from opposite the mini-split unit in bloom room.

4) Either way an air-exchange between veg and bloom in a not quite sealed environment could have you LEAKING SMELL. What is your odor control situation?

 

[hotboxes]

personally I don't think your temps. are all that bad. I had a room split into a veg and flower room split by a 1x3" wall covered by panda plastic and my temps varied from 75 to 78 degrees in the flower room and 70 to 75 in the veg room. these temps are about what you are looking for when growing. If you are using Co2, personally I would seal the flower room off from the other too keep the Co2 from escaping. Are you exhausting the flower room out of the room entirely? If so you are wasting the Co2 because it is eventually being sucked out of the room. Plus when using Co2 you can run your room at higher temps. without the worry of negative effects to your plants. I had always thought that 75 to 78 degrees was about perfect for growing without having negative effect, and I never had a problem hope this helps and good luck.

 

[BattleAxe]

Too bad you didnt get a mini-split that operates two units

I thought of a dual zone but then reconsidered as I was confident in my abilities to exchange the air effectively. The cost difference was $500 too bad I didn't have the loot, somethings are just worth paying for.

So you are recirculating 747 cfm between bloom and veg, ok goddamn that should do it...

I thought so too...

1) If you had active intake to the veg causing co2 loss, now that you have only exhaust perhaps it is now pulling warm air from where your co2 was previously leaking.

This is a possibility but I would still think that it should pull mor air from the bloom room being that the intake is bigger with 2x8" holes versus a 1/4" crack that could be weatherstripped better.

2) Perhaps if you switched your veg reflectors to air-cooled, and attached to your current exhaust, cool air gets pulled out of bloom into veg, warm air pulled through veg lights and sent back into bloom.

This is a good idea. My veg hood is air cooled and is on the loop that exhausts from the space. It is a closed loop that pulls intake from the inside of the house through all the lights and completely out of the space, it doesn't mix with the atmosphere. I did however remove it from the loop for testing purposes and without it being vented the temp in veg climbed +2 degrees.

3) The side of the room the passive intakes are on, is it far away from the mini-split unit? You want your warm-air return from the veg coming out near the mini-split unit, and the cool-air intake to veg being pulled from opposite the mini-split unit in bloom room.

it is like this except that the warm air return is on the same wall as the intake, its the only way it would have worked for this particular setup, I would have had to run ducting through walls of other living spaces to make the return near the mini split.

4) Either way an air-exchange between veg and bloom in a not quite sealed environment could have you LEAKING SMELL. What is your odor control situation?

The space is sealed, per se. There is no air exchange between the two rooms and the outside world, only exchange between the two areas, veg and bloom. The lights are on a closed loop as said before. I have a huge can filter that scrubs all air in flower room, I still maintain neg pressure throughout the space any leakage should be covered by the scrubber. I have plants in bloom and my wife has a keen sense of smell, she can't smell a hint of it, even when she enters the dungeon to tell me to come eat dinner.

I'll get some better pics of the entire setup to clear up any misconceptions.


Thanks for the input though DL, nobody else has offered anything and I know cats are reading it.

 

[BattleAxe]

personally I don't think your temps. are all that bad. I had a room split into a veg and flower room split by a 1x3" wall covered by panda plastic and my temps varied from 75 to 78 degrees in the flower room and 70 to 75 in the veg room. these temps are about what you are looking for when growing. If you are using Co2, personally I would seal the flower room off from the other too keep the Co2 from escaping. Are you exhausting the flower room out of the room entirely? If so you are wasting the Co2 because it is eventually being sucked out of the room. Plus when using Co2 you can run your room at higher temps. without the worry of negative effects to your plants. I had always thought that 75 to 78 degrees was about perfect for growing without having negative effect, and I never had a problem hope this helps and good luck.

Room is sealed. The only problem is that I am in DIY DWC tubs and my res temps are around 75 which is a gateway for root root and other pathogens, not to mention my plants are potentially suffering from lack of DO that is created by increased temps. I'm not concerned with plant and canopy temp, I understand CO2 enables a plant to handle higher temps. My concern is the funkies that will come to the party in the res at these temps. A chiller is not an option right now, I plan on one for the future when I step up to RDWC. In the meantime, I would like to get these rooms within 2-4 degrees of each other.

 

[whodare]

my temps in bloom are 75 -80

actually youd be better at 80 since your using co2 and without elevated temps your just wasting it...


edit i see the problem, yea your kinda screwed but a small chiller isnt much money

 

[hotboxes]

yeah I just seen your set up on your hydro page and commented on your algae problem. personally I wouldn't even mess with DWC until you can get a chiller your always going to have rez. problems with out a chiller unless you run RDWC and then you deff. need a chiller. again just my .02 cents.

 

[Grønn]

Could you post a diagram?

It's really difficult to visualize air-flow without a clear idea of room sizes and entry exit points for ventilation.

To me it sounds like your veg-room ventilation might be short-circuiting, i.e not emptying air from the whole room, but just an area between passive intake and active out.

 

[BattleAxe]

yeah I just seen your set up on your hydro page and commented on your algae problem. personally I wouldn't even mess with DWC until you can get a chiller your always going to have rez. problems with out a chiller unless you run RDWC and then you deff. need a chiller. again just my .02 cents.

I heard that. I probably should just scrap it but I have too much time and loot into it. I am looking for a chiller as my next investment. I want to be that guy that beat the odds with DWC and no algae just because I was able to keep the enviro controlled.

 

[hotboxes]

If you just switch to Coco I will bet you will save more than just trying to control everything. I felt the same way as you are now when I was using DWC. I had people telling me all the time just switch to coco and you won't have anymore problems and like you I kept sayn I want to master this before I try something else but believe me I spent more loot trying to get it right before I just went ahead and switched. you can take your plants from DWC and go right to coco with out any negative effects I promise you I did it, just layer the Coco around the roots till they are totally covered and Coco is pretty cheap and you won't have to worry about rez temps any more its like growing in dirt but you have all the benefits of hydro like the massive growth. If you want take 1 plant and switch it to Coco and find out for your self. Like I said before you will not be disappointed and will probably just switch all together.

 

[whodare]

^^^ good advice, coco might be the way to go to end this run until you get a chiller...

 

[BattleAxe]

If you just switch to Coco I will bet you will save more than just trying to control everything. I felt the same way as you are now when I was using DWC. I had people telling me all the time just switch to coco and you won't have anymore problems and like you I kept sayn I want to master this before I try something else but believe me I spent more loot trying to get it right before I just went ahead and switched. you can take your plants from DWC and go right to coco with out any negative effects I promise you I did it, just layer the Coco around the roots till they are totally covered and Coco is pretty cheap and you won't have to worry about rez temps any more its like growing in dirt but you have all the benefits of hydro like the massive growth. If you want take 1 plant and switch it to Coco and find out for your self. Like I said before you will not be disappointed and will probably just switch all together.

^^^ good advice, coco might be the way to go to end this run until you get a chiller...

Those are the words that a determined man hates to hear lol. I'm open to it though. Would you use hydroton in conjunction with the coco?

Theoretically speaking, if I was to be able to get this room stable at low 70s I should be ok w DWC. That is my ultimate goal but if all else continues to fail, I will def explore the coco. I just hate admitting defeat, I have a couple magazines left before I need to retreat and regroup.

 

[hotboxes]

the only way you can be successful with DWC is keeping your WATER temps at or below 65 degrees constantly and this is impossible with out a chiller unless you want to be putting Ice packs in your buckets every 2 hours. Also it's not defeat it is adapting and over coming your problems. your room temps have nothing to do with your buckets besides the water coming up to room temp. and personally they are perfect for what you are growing .

 

[BattleAxe]

Could you post a diagram?

It's really difficult to visualize air-flow without a clear idea of room sizes and entry exit points for ventilation.

To me it sounds like your veg-room ventilation might be short-circuiting, i.e not emptying air from the whole room, but just an area between passive intake and active out.

Here ya go Gronn. What are your thoughts after seeing the diagram?

 

[BattleAxe]

the only way you can be successful with DWC is keeping your WATER temps at or below 65 degrees constantly and this is impossible with out a chiller unless you want to be putting Ice packs in your buckets every 2 hours. Also it's not defeat it is adapting and over coming your problems. your room temps have nothing to do with your buckets besides the water coming up to room temp. and personally they are perfect for what you are growing .

This is all sound advice and I do appreciate it all. RDWC is where I would eventually like to end up. So instead of spending time and money to learn about growing coco, I can just find a craigslist chiller, it would probably be about the same work and loot required to switch mediums and then to switch again when I can step my game up. CL 1/4 HP Chiller = $250 learning to grow in coco = ? hours research, loot, wife bitching, etc. Probably about the same in total costs and actually more cost effective given that RDWC is the end state in mind.

You're probably right though. Anything above 70F is asking for trouble in DWC. I'm stubborn and have been able to push and grow the plants with mid 70s res temps, I could probably be growing more if the temps were cooler. Looks like I need a chiller but that still doesn't explain why my room is defying the laws of ventilation.

 

[whodare]

the only way you can be successful with DWC is keeping your WATER temps at or below 65 degrees constantly and this is impossible with out a chiller unless you want to be putting Ice packs in your buckets every 2 hours. Also it's not defeat it is adapting and over coming your problems. your room temps have nothing to do with your buckets besides the water coming up to room temp. and personally they are perfect for what you are growing .

true shit, you probably could pull an ok harvest continuing on your current path but switching to coco will probably do you better. if you switched you could raise room temps and then youd actually be utilizing the extra co2... next run you be able to kill it in dwc the chiller is key though...

 

[BattleAxe]

true shit, you probably could pull an ok harvest continuing on your current path but switching to coco will probably do you better. if you switched you could raise room temps and then youd actually be utilizing the extra co2... next run you be able to kill it in dwc the chiller is key though...

Agreed. I just called on the chiller, lady is willing to trade for some misc grow gear that I have laying around and some cash

Now the problem is finding a good writeup that shows me how to make a DIY RDWC using tubs. Anyone have any suggestions. I think if I could knock out the construction aspect of it this weekend if I get a jump on it. Anyone have any good links?

 

[Grønn]

Here ya go Gronn. What are your thoughts after seeing the diagram?

Just a couple of thoughts.

Your veg room is allways going to be hotter than your flower room, seeing as you are adding your flower room air to cool your veg, but 9 degrees is a lot.
If your airflow between passive and inntake is short circuiting, and if that 1kw mh isn't efficiently air-cooled. That could be the reason for the high temp differential. Although an 8" should be plenty for the job.

Nice plants btw.

 

[Grønn]

You might also consider a 6" on the passive intake for the air-cooling loop. Looks like a lot of bends, ducting, y-pieces and hoods for the 8" to pull through.