My room defies the laws of ventilation please help

[BattleAxe]

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.

Thanks!

I know that the bends are not ideal but it was the lesser of two evils. The wall that the split is mounted on goes to a backyard and the closed loop exhausts into another living space. I would have been pulling outside air into the house which wouldn't be ideal so I opted for this design. What I didn't add in the drawing is that there is 2 8" booster fans that supplement the ventilation because of all the funky bends.

I think you are on to something with your theory of the short. I just went and hooked up a booster fan to a piece of ducting and a booster fan that directs air away from the wall and it cooled the veg room to 76. I'm now at 70 and 76. I think the fan is rated at 454 CFM which still allows for neg pressure about the whole space for odor and CO2 control. I guess this is a band aid til the perm solution arises.

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.

I probably should have started with a 6" intake, because it would have been easier to go up instead of go down now that the hole is there. Hasn't been an issue so far. Only two hoods are being used and each is cool to the touch as the exhaust is constant.

Thanks a lot Gronn for your advice here. This is a start

What would you guys do in this case? At this point I'm thinking that I am going to have to force air to that side of the room via a blower or fan of some type and just have to deal with the fan placement on the floor.

 

[BattleAxe]

I just thought about something....

Theoretically speaking...If I were to attach a long piece of ducting to my exhaust fan and place it in the far corner of the veg room basically extend it across the entire room, it should force air to flow across the entire room and maximize the cooling. Does that sound about right to anyone? This way, I can do away with a fan and ducting on the floor.

 

[olddirtybastard]

hey battle, cant reallly comment on the ventilation without seeing it, but about the res temps i think people really blow out of proportion the dangers of temps around 75.

Ill tell you in my opinion 70-75 is just fine, its what my res is usually at and ive never had root rot or anything like that because its well aerated mainly. i would only worry if your res temps were around 80 or more.

A chiller is a great thing to have though, save up for a good one and remember you dont really need it that much.

 

[Grønn]

I just thought about something....

Theoretically speaking...If I were to attach a long piece of ducting to my exhaust fan and place it in the far corner of the veg room basically extend it across the entire room, it should force air to flow across the entire room and maximize the cooling. Does that sound about right to anyone? This way, I can do away with a fan and ducting on the floor.

Sounds like a good idead.

Check out this thread for good ventilation advice:
https://www.icmag.com/ic/showthread.php?t=112862

When looking at this diagram:

You can see by the red lines that you could expect a temp diff of 4 degrees from ambient when using a 750cfm extraction fan in a room with a 1000w.

With your 9 degree temp diff the diagram says that your effective airflow is somewhere in the region of 350cfm (green lines). So there should be plenty room for improving efficiency and getting your temp diff down towards that 4 degree mark, but 76 sounds like a good improvement also.

Sorry about being unclear on the 6" intake comment - was talking about adding a 6" inline fan to the intake to get more air-movement around the air-cooling loop, but if you have a couple of 8" booster fans helping your inline you should prolly be ok with that.

Ventilation is a bitch. Best way is to just sit in the room and visualize how the air-flow moves and the forces affecting it. Make sure fans aren't working against each other and try to get max efficiency out of your fans.

gl - sounds like you are getting closer to as good as it's gonna get anyways.

 

[hotboxes]

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.

Yeah I hear you. I'm not trying to sell you on the Coco Idea It is totally up to you how you grow your plants. I was just giving you a way to save your plants till you worked out your ventilation problem out.

when I was in your situation I didn't have the spare cash to go and get a chiller I pretty much had to switch to a different way or I was going to loose a lot more than I had already. I just set up a drip system for really cheap and I had a recycle Timer laying around, threw that on there and just refilled my rez's when they were low. But I would for sure get rid of the hygrozyme that will end the algae problem good luck man and hope you get everything worked out.

 

[hotboxes]

I would seal the flower room totally If you are using Co2. close off your exhaust and put a scrubber in there unhooked from you exhaust. you will save the A/C a lot more. If you keep all the Co2 and the A/C in there it would help more. and the scrubber will constantly clean the air. Just leave the intake hooked up and it will eventually push the air into your veg room.

Another thing with all those funky bends I would have a booster fan on each light they are fairly inexpensive so you can help push the air a lot better. just a thought. I just seen the diagram and you should have something pulling the air into your room put 2 8" boosters on those 2 intakes. Is that a Y split from your flower room lights going into your veg room? If so take that out of there and keep it in its own room. Close the loop in the flower room, and just put a fan or something on the light in the veg room. Imo the Y is causing you negative pressure.

 

[Dislexus]

I already suggested air-cooling the veg light and ducting it to the veg-to-flower exhaust. Still think you should do it.

But really man... I wish you could just go back and install a multi-unit minisplit ac... if you're fucking around with co2 and dwc you can't cut any corners

 

[olddirtybastard]

oh yeah one more thing, i wouldnt worry much about your veg room. My veg room is crap and barely set up to keep plants alive mainly. the flower room is where you want to focus all your efforts.

I always have plenty of time to veg the next rotation so i dont care if their grow space is a little too hot, or whatever. Unless you are in a real hurry to veg your plant to the desired height.

i would suggest you seal your flower room if you are going to use co2, isolate it and focus on controlling the environment precisely in there. then for your veg room just use an exhaust fan to circulate the air, and use fluorescent lighting to keep the heat below 85-90. the two rooms do not have to be connected.

 

[Shred42O]

you could always use a frozen water bottle to cool your dwc

 

[BattleAxe]

I'm happy to report to you guys that I have solved my ventilation issues. At least for the time being anyway. I wanted to thank everyone for their advice and suggestions.

Basically, I am an idiot. I was overthinking this shit and filling my grape with so much info that I overlooked some basic shit. First off, I was measuring the temp drop between the two rooms at canopy level - WRONG. When I started taking temps at various points in the room, I was finding that the temps were remaining constant across the room at 2-3 degree drop. I added some more ducting to my exhaust fan so that it is pulling air from the other side of the room, thereby increasing the airflow. So basically the ventilation design is the same as the one I posted with longer ducting on the exh fan. Right now the conditions are: bloom = 74 Veg = 77. With bloom canopy = 80.2 veg canopy = 81.0. Both reservoirs are drifting between 74/75



Given that their is a CO2 boost in the room, I think I am going to run with this for now. As long as I can keep my res temps in check, I should be g2g.

hey battle, cant reallly comment on the ventilation without seeing it, but about the res temps i think people really blow out of proportion the dangers of temps around 75.

Ill tell you in my opinion 70-75 is just fine, its what my res is usually at and ive never had root rot or anything like that because its well aerated mainly. i would only worry if your res temps were around 80 or more.

A chiller is a great thing to have though, save up for a good one and remember you dont really need it that much.

Agreed. I know people who have rot at 75 and I know those who grow ginormous plants in 77. Given that I have grown these plants in these same conditions, I think I should be g2g. If not, it will be a valuable life lesson. I am gonna step up to a chiller but not right now, right now. When I do I am really thinking about making me some bio buckets!

Sounds like a good idead.

Check out this thread for good ventilation advice:
https://www.icmag.com/ic/showthread.php?t=112862

When looking at this diagram:

You can see by the red lines that you could expect a temp diff of 4 degrees from ambient when using a 750cfm extraction fan in a room with a 1000w.

With your 9 degree temp diff the diagram says that your effective airflow is somewhere in the region of 350cfm (green lines). So there should be plenty room for improving efficiency and getting your temp diff down towards that 4 degree mark, but 76 sounds like a good improvement also.

Sorry about being unclear on the 6" intake comment - was talking about adding a 6" inline fan to the intake to get more air-movement around the air-cooling loop, but if you have a couple of 8" booster fans helping your inline you should prolly be ok with that.

Ventilation is a bitch. Best way is to just sit in the room and visualize how the air-flow moves and the forces affecting it. Make sure fans aren't working against each other and try to get max efficiency out of your fans.

gl - sounds like you are getting closer to as good as it's gonna get anyways.

Many thanks for this. This graph put things into perspective for me. Was that in the ventilation 101 sticky? Extending the exhaust tail was the key here. That and, I think my 2x8" intakes on the shared wall were being inhibited by the ducting Ss. I have since ordered some dark room louvers that Philthy turned me on to. System is working now as planned, passive intake and shared exhaust with desired conditions.

Yeah I hear you. I'm not trying to sell you on the Coco Idea It is totally up to you how you grow your plants. I was just giving you a way to save your plants till you worked out your ventilation problem out.

when I was in your situation I didn't have the spare cash to go and get a chiller I pretty much had to switch to a different way or I was going to loose a lot more than I had already. I just set up a drip system for really cheap and I had a recycle Timer laying around, threw that on there and just refilled my rez's when they were low. But I would for sure get rid of the hygrozyme that will end the algae problem good luck man and hope you get everything worked out.

NW bud, I do appreciate the advice. Although I did not decide to go coco I did toy with the idea that if I do need to make a switch that I could just copy the manifold design that I made for my DIY aero cloner and intstall into my tubs. I could keep the res temps a bit higher and all of the tubs and lids could be integrated into the new aero design. I have since decided to do away with the hygrozyme.

No algae in any of my res but my ST mom, she is however still pumping out new growth and I suspect that the algae present is just some remnants of the original. It doesn't seem to be multiplying so that is a good thing as It will most likely be resolved with few flushes and res changes.

I would seal the flower room totally If you are using Co2. close off your exhaust and put a scrubber in there unhooked from you exhaust. you will save the A/C a lot more. If you keep all the Co2 and the A/C in there it would help more. and the scrubber will constantly clean the air. Just leave the intake hooked up and it will eventually push the air into your veg room.

Another thing with all those funky bends I would have a booster fan on each light they are fairly inexpensive so you can help push the air a lot better. just a thought. I just seen the diagram and you should have something pulling the air into your room put 2 8" boosters on those 2 intakes. Is that a Y split from your flower room lights going into your veg room? If so take that out of there and keep it in its own room. Close the loop in the flower room, and just put a fan or something on the light in the veg room. Imo the Y is causing you negative pressure.

My bloom isn't completely sealed as it shares the ac with the veg but the co2 doesnt leave the entire space, it is only recirc'd between the veg and the bloom, neg pressure keeps it in. I know this isnt ideal but I have read some convincing arguments that CO2 supplementation in veg is beneficial. That and, it allows me to share the ac so it is an acceptable loss.

I already suggested air-cooling the veg light and ducting it to the veg-to-flower exhaust. Still think you should do it.

But really man... I wish you could just go back and install a multi-unit minisplit ac... if you're fucking around with co2 and dwc you can't cut any corners

veg light is air cooled with the rest of the closed loop and is still cool to the touch. I did switch it just to see and it made no difference with temps. I do suspect that it made my AC work harder as now it was battling the exchanged heat back into the bloom.

Buying another split isnt an option right now. If I could do that, I would have 5 chillers.

oh yeah one more thing, i wouldnt worry much about your veg room. My veg room is crap and barely set up to keep plants alive mainly. the flower room is where you want to focus all your efforts.

I always have plenty of time to veg the next rotation so i dont care if their grow space is a little too hot, or whatever. Unless you are in a real hurry to veg your plant to the desired height.

i would suggest you seal your flower room if you are going to use co2, isolate it and focus on controlling the environment precisely in there. then for your veg room just use an exhaust fan to circulate the air, and use fluorescent lighting to keep the heat below 85-90. the two rooms do not have to be connected.

I know that I could get away with it but personally, I strive for best conditions whenever possible. I have learned that life is all about controlling variables, the less that are present the easier my life is. Hopefully my efforts in this area rewarded in harvest.

I thought about using CFLs but now that I have gotten it right for now will just keep that one in my back pocket.

Thanks for all your help bud.

you could always use a frozen water bottle to cool your dwc

Good point. I actually thought about that as I was bumping up the ambient temps in my space. I do daily chores, I could drop some iced up 2l bottles in the morning on a daily basis. That would serve as a constant reminder to me when I wanna buy some stupid shit instead of saving for a chiller.

Thanks again for all your fine help fellas!

 

[MIway]

And some root porn for all you pervs.

Did you snag your chiller? Just found the thread, but that pic shows a bunch of rot that happened earlier, with new white growth coming in... but if you've raised your room temps, then i would suspect you will bring back the rot.

 

[BattleAxe]

Did you snag your chiller? Just found the thread, but that pic shows a bunch of rot that happened earlier, with new white growth coming in... but if you've raised your room temps, then i would suspect you will bring back the rot.

No chiller. You really think that is rot as opposed to the nutes staining the roots? This is my first run so I don't have anything to compare it to but I would suspect that if this was root rot, the plants would be exhibiting some signs of stress or some type of symptoms?

 

[BattleAxe]

Did you snag your chiller? Just found the thread, but that pic shows a bunch of rot that happened earlier, with new white growth coming in... but if you've raised your room temps, then i would suspect you will bring back the rot.

bump for a second opinion on the rot. If this were rot, how is it possible for new roots to grow out of old roots that have rotted? IIRC, root rot = root dead?

Also, although the ambient temps have been raised, each res is right about or below 75F.

 

[NiteTiger]

Ok, my connection is geeking out, so I may be restating something, can't check. If so, sorry.

You may have too much ventilation. Did a post on it in the main Grower's forum called "Thought on max airflow or good advice sours" I'd link, but again, iffy connection.

Basically, your addirion of an intake may have increased airflow to a point that actually reduces cooling effeciency.

 

[NiteTiger]

Easy cheap chiller - Copper tubing, bucket, pump, saltwater, dorm fridge.

 

[BattleAxe]

Easy cheap chiller - Copper tubing, bucket, pump, saltwater, dorm fridge.

I just realized that I have an old water cooler that I am pretty sure has a water chiller in it as it has a hot and cold option. Now I just have to get it apart when I have some time.

I am a bit confused with your theory on over ventilating. I didn't think that was possible in this case. In simple terms, the bloom room has the ac and the cooler temps, I am trying to get as close to those temps as possible by exchanging as much air between the two as possible. My understanding of the principles of ventilation tell me that if I intake more air while maintaining positive pressure, I will exchange more air between the two thereby cooling my veg more efficiently with the air from the bloom.

Please elaborate a little.

 

[Dislexus]

Woops my bad I didn't digest that you already have your veg lights air-cooled.

What your saying should work on principle BattleAxe and you seem to have the CFMs to pull that off, thats why I think there is another issue going on.

Like your veg room is somehow drawing hot air from the attic or walls or something. Regular ceiling light fixtures can sometimes have a sizeable hole cut in the ceiling.

I dunno something is wrong man.

 

[BattleAxe]

Woops my bad I didn't digest that you already have your veg lights air-cooled.

What your saying should work on principle BattleAxe and you seem to have the CFMs to pull that off, thats why I think there is another issue going on.

Like your veg room is somehow drawing hot air from the attic or walls or something. Regular ceiling light fixtures can sometimes have a sizeable hole cut in the ceiling.

I dunno something is wrong man.

NW man, I know how it is. I agree that there is another issue and I suspect that it is with the intake ports and the long Ss of ducting that I have on them, I have a U on 1 and a 8' S on the other one. I think the ducting is reducing airflow and like you say, the exh fan is pulling warm air from outside the room, increasing temps. In theory, once I install those louvers, I should be able to maximize airflow for my fan. It's a 747 CFM and each 12x12 louver offers 400 CFM.

 

[NiteTiger]

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 .

Incorrect, you can sucessfully do DWC w/o a chiller just fine. There are many more DWC grows done on here without chillers than with them. Stating that you need a $400 piece of equipment to run one of the cheapest and easiest hydro setups there is just silly.

Water temps of 68F are fine and your water temps are usually at least a few degrees cooler than the air temps, so cooling your room is an easy way to avoid needing a chiller.

Plus, higher water temps do not spell certain doom, you just need to take precautions. I've seen water temps in the 80s do just fine with no more precautions than religous cleaning and some peroxide in the fresh nute solution that was changed every other day.

Time intensive and nute expensive? Yes. But he was in a position where he couldn't afford to address the heat issue effectively, so he adapted to account for the potential problem.

Speaking in absolutes is a bad habit to get into.

 

[NiteTiger]

Ok BattleAxe, now that my connection is a bit better, let me say that first, you don't have a temp issue. You're actually low for getting the most out of your CO2.

High temps (90+) cause the plant to open up a bit and respirate faster, there by making more use of the higher CO2 concentration. To be honest, CO2 isn't going to make any noticeable difference in this grow. Without having your system dialed in, your nutes just right, tweaked specifically to your stabilized genes that you know inside and out, you won't even be able to tell if it had any effect at all. Save your gas for now.

Where is your exhaust in this vent system, and what size fan and scrubber do you have on it? Couldn't figure that out from your diagrams. Between the diagrams and you explanations, it almost sounds like you have an active intake and no exhaust, but that can't be right, so I must have missed it somewhere.

Did you read the post I told you about? It explains how "maximum airflow" advice can work against you in a cooling scenario. The effect is clear, when you opened up intake, temps went up. I'm not going to retype the article here.

TL;DR - Probably won't like my advice, but... You don't have a temp problem. Kill the CO2, cover the buckets to sheild from direct light, and take steps to prevent pathogens. You're fine, enjoy your plants!