1000w Cool Tube Problems

Hey everyone, first post here!

I have my room 90% set up. Currently I have a 3x3 veg tent and a 4x4 flower tent right beside it. I have an ac unit behind both tents pushing cold air towards the intakes of them. The carbon filter and 8” can fan are also behind the tents in the same area as the AC. I have a 4” can fan as an intake for the flower tent and a circulating fan inside to push air around.

as for the cool tube and 1000w, the intake to the cool tube is inside the tent, assisting with negative pressure. On the other side of the cool tube I have ducting that runs out the tent and into the ceiling, with a fan at the end to help push air over the light, through the ducting, and into the ceiling.

My RH is around 30%, with the 1000w and the AC in the back set at 68°, my temps inside the tent were still hitting 88°.

For the meantime I have swapped to a 600w HPS in the 4x4 flower room and my temps are maxing at 77° which I’m happy with, I just wish I had the 1000w to at least get 62.5w per square foot.

Any ideas on what to do? Should anything be moved? Should I get a stronger fan anywhere?

Thanks everyone!!!

Might be tricky for space but I would have it like this if possible.

Filter >Fan>cooltube>duct out. All inside tent (sounds like filter is outside which is odd)

Do you have your vent flaps open too since the 4" wont be close to keeping up with the 8" extractor?

Where is your thermometer ?

Can you take a photo of your tent how it is so I can see it all?

Welcome to RIU btw

Obviously where the ducting goes out the tent you would vent it to out the room not back into the room

coreywebster said:

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Obviously where the ducting goes out the tent you would vent it to out the room not back into the room

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Corey try and cut down on bends when using cool hoods or tubes.You will be surprised how much effects the temps .You be far better with filter to exhaust, attached via a belt strap.Then straight to the light then other end of light if possible straight shoot ,out the tent or room.I love cool hoods all I have used since they very first come out,then a few year before they was even hydroponic shops ,i was using a perspex tube and fan filter in this way .Same with deep water culture ,a friend of mine was doing that around 5/6 years before it was in magazines like high times.The temps this winter have been weird, people are saying it's been mild .But it's the first year ,I can remember that temps was that low in my room I had to use heaters .Gotta a funny feeling that we are gonna have a hot summer,so that cool tube ,may mean the difference between, been able to grow through summer or not.I know a fair few that stop growing in summer ,they are large growers mind ya ,not like me do it for y self .But I tell them all time there are ways of growing through hottest summer.

coreywebster said:

Might be tricky for space but I would have it like this if possible.

Filter >Fan>cooltube>duct out. All inside tent (sounds like filter is outside which is odd)

Do you have your vent flaps open too since the 4" wont be close to keeping up with the 8" extractor?

Where is your thermometer ?

Can you take a photo of your tent how it is so I can see it all?

Click to expand...

Thanks for the reply Corey! Yeah it’s a weird setup right now with my filter, Its just so large it won’t fit in my tent with the cool tube and it doesn’t smell much yet so it’s just there as a main room exhaust. the reason I don’t have much space is because the tent is 6’ tall, and the sides kind of lean in towards each other kind of like so;

____
/ \
/ \
| |
| |
—————

I really only have space for the light at the top there. I don’t have the vent fans open, should I? Is the reasoning behind that because the 8” carbon filter and fan are sucking potential air away from the 4” intake fan I have for the flower tent?

Lights on is in 6 hours so I’ll take a picture of the setup. I really want to make the 1000w work, I’m going to see if maybe putting the 8”can fan on the exhaust of the cool tube will suck air fast enough to keep the air around the bulb cool. Week 2 of flower just began so I have a week or two left until the stank starts to get noticeable.

Here’s a drawing of what the tent and the room itself looks like

SoCalCraw said:

Here’s a drawing of what the tent and the room itself looks like

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Yeah man, that's not going to work in many ways.

Firstly your taking air out of your tent through your cooltube which is unfiltered. You don't mention the type of fan that's on the other end?

Then your 8" proper fan and filter is independent to both your tents, its literally doing nothing, its cleaning air that doesn't need cleaning because its going through your flower tent. Its probably sucking up half your ACs cool air too instead of removing heat from the tent.

The best fan you have is been used to just suck air out of the room and whatever fan you have on the cooltube is pulling stink air which will fill the space your pumping it to.

I can appreciate what your saying about your limited height and width at the top because I used to veg in a loft tent.

Now I agree with tyke about bends in ducting but in the case of a single cooltube and an 8" can fan it can take plenty of restriction before it isn't capable of doing the job.

My old flower set up used to be an 8x4 tent with 8" Isomax fan, 8" rhino filter and 3x 600 hps all in cooltubes in a straight line. The lights ran down the middle, the fan was longer than the filter so they ran along side. There were two 90 degree bends ( plastic ones) then a 90 degree bend in the duct. Not only did it run all year round through any conditions it also had enough pull to draw air into the room passively through a chimney which led to the basement 3 storeys below.

So im full confident an 8" CAN will easy do the job on a single cooltube and 1000w hps as long as things are in the right place.

There are two ways of doing it.

Filter>Fan>Tube>duct out
Filter >Tube>Fan>duct out.. This option is the least favourable since we don't really want to pull very hot air thorough the fan, though a CAN will handle it since it has sealed bearings.

What I would do if possible, I seem to remember there are two duct socks in the apex of the tent opposite each other and one in the roof going straight up. If that's the case I would do this.

Diagram to follow. (poorly drawn)

This is reliant on you having two duct socks in the top of the walls and one in the ceiling.

Again I agree with the concept of keeping bends to a minimum but it cant always be done and if you use dryer duct after the fan and before the cooltube blowing the air through it expands to make a pretty smooth surface which doesn't create too much turbulence. If not the 45-90 degree plastic or metal duct bends will be needed.

If you cant do it this way due to less duct socks than I think you have then you may have to suck the air through the cooltube Like ….. Filter>tube>fan>duct out. In which case you will have the fan directly clamped to the cooltube and the filter with a bend on the other end, it may mean the filter it on the sloping part of the roof or even doubled back with a full 180 degree bend.
(edit, or the fan can be just outside the tent pulling through tube and filter)

You do need the filter in the tent when your ducting the heat out of the room in any way which is really what you need to be doing.

Also I mentioned the thermometer placement , which is just an added extra really and not your priority, but it should be out of direct light, either above the light line or shaded by reflective material like white card. Purpose been you don't want light warming it up.

As for the intake your using, when set up properly you will be removing all the heat from the tent and the heat from the light in one swoop , been your 8" is massively more powerful than 4" even after all the reduction in performance has been taken account of ( probably 20-30% reduction) you want the lower flaps open too or the lower duct socks, since the extraction fan can only take out what can be replaced. The 4" wont keep up and will actually restrict the airflow, it will help, but those loft tents actually seal up pretty well when everythings shut so open those to allow the 8" extractor to move as much air as it can.

@tyke1973 I don't disagree with your point on bends and filters ect reducing airflow, sometimes every little bit makes a huge difference.

I have run far more restrictions on more wattage with similar powered fans though.

Here is the test of the 8" CAN showing the difference in performance with 1m duct, 4m duct, 4m plus 2 90 degree bends ect..


And yeah bro I think we are gona have a wopper summer mate. Thank god I don't run that much wattage these days.

coreywebster said:

As for the intake your using, when set up properly you will be removing all the heat from the tent and the heat from the light in one swoop , been your 8" is massively more powerful than 4" even after all the reduction in performance has been taken account of ( probably 20-30% reduction) you want the lower flaps open too or the lower duct socks, since the extraction fan can only take out what can be replaced. The 4" wont keep up and will actually restrict the airflow, it will help, but those loft tents actually seal up pretty well when everythings shut so open those to allow the 8" extractor to move as much air as it can.

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thanks so much for the helpful explanation, I’m going to go home after work and implement this, though placement might have to be different since I’m working witha totally height of 6.5’.Here’s what I’m thinking let me know if this makes sense based on your explanation;

In the photo there is no filter, maybe that can go inside the tent, then ducting from that outside the tent to the can, then back up and through the light and ducted our the tent. Now I’m just wondering this way how there is going to be negative pressure or do I have to use the 4” fan as an exhaust?

sorry if I’m being repetitive, this has been the bane of my existence this last couple of weeks

SoCalCraw said:

In the photo there is no filter, maybe that can go inside the tent, then ducting from that outside the tent to the can, then back up and through the light and ducted our the tent. Now I’m just wondering this way how there is going to be negative pressure or do I have to use the 4” fan as an exhaust?

sorry if I’m being repetitive, this has been the bane of my existence this last couple of weeks

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No need to apologise dude, we've all faced taxing grow conditions and ive set up so many grows it comes as second nature, though my explanation skills are lacking.

Yeah you describe it how I see it. As long as that filter is in that tent and there's a fan sucking through it there will be negative pressure and importantly clean air.

The placement of the fan is preference , be it sucking through tube or pushing through tube, the pushing was always the recommended option where possible to save very warm air going though the fan and drying the bearings out, but fans are a lot better than days gone by so either will work and work better than you have it now.

Disclaimer here. Its not really recommended to duct straight into a roof space. But that's another story.

Im just trying to help get that fan filter and cooltube combo set up right to remove the heat.

The issue of mould will come down to humidity % in the loft space. Hopefully its well ventilated up there.

coreywebster said:

Disclaimer here. Its not really recommended to duct straight into a roof space. But that's another story.

Im just trying to help get that fan filter and cooltube combo set up right to remove the heat.

The issue of mould will come down to humidity % in the loft space. Hopefully its well ventilated up there.

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Alright Corey, I took your advice and I'll explain to you what I've got going on now.

The AC unit is still behind both tents, I bumped it up to 72 from 68. I checked the hot air exhaust that was going into my ceiling, it was hot but only %10 humidity so I don't think mold will be a concern. I also checked my exhaust from the flower tent into the ceiling and it was the same RH as the exhaust of the AC.

I removed the 8" CAN fan from the back area, I think you were right it was sucking the cold air out before it had a chance to get to the flower tent and the 4" intake fan for it was only impeding air flow. I pretty much removed everything from the tent other than the light lol.

I set up the tent as follows; Carbon filter hanging at around 5' tall with ducting (6' of ducting) out one of the top holes leading to the CAN fan. On the other side of the CAN fan, the air then pushes into ducting (5' of ducting), goes back into the tent, over the light, with ducting at the other end of the light that runs into the ceiling as exhaust (6-7' of ducting).

I opened up the bottom 6" intake hole to allow air to get pulled through passively, as well as one of the two flaps (I got scared I'll try both later hahah)

I ran it for the first time overnight and checked my low and high this morning. My low was 65 for night time and high was 73, RH around 30 and I'm halfway through the second week of flower

I THINK WE HAVE FIGURED THIS OUT!!! I was so busy yesterday moving everything around I didn't think to take a video but I will when I get home today!

SoCalCraw said:

Alright Corey, I took your advice and I'll explain to you what I've got going on now.

The AC unit is still behind both tents, I bumped it up to 72 from 68. I checked the hot air exhaust that was going into my ceiling, it was hot but only %10 humidity so I don't think mold will be a concern. I also checked my exhaust from the flower tent into the ceiling and it was the same RH as the exhaust of the AC.

I removed the 8" CAN fan from the back area, I think you were right it was sucking the cold air out before it had a chance to get to the flower tent and the 4" intake fan for it was only impeding air flow. I pretty much removed everything from the tent other than the light lol.

I set up the tent as follows; Carbon filter hanging at around 5' tall with ducting (6' of ducting) out one of the top holes leading to the CAN fan. On the other side of the CAN fan, the air then pushes into ducting (5' of ducting), goes back into the tent, over the light, with ducting at the other end of the light that runs into the ceiling as exhaust (6-7' of ducting).

I opened up the bottom 6" intake hole to allow air to get pulled through passively, as well as one of the two flaps (I got scared I'll try both later hahah)

I ran it for the first time overnight and checked my low and high this morning. My low was 65 for night time and high was 73, RH around 30 and I'm halfway through the second week of flower

I THINK WE HAVE FIGURED THIS OUT!!! I was so busy yesterday moving everything around I didn't think to take a video but I will when I get home today!

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Why is this post so complicated?

Just make it all linear... ac duct into flower room and flower room ducted into veg room and then out.

Are you running co2?

It’s co

oill said:

Why is this post so complicated?

Just make it all linear... ac duct into flower room and flower room ducted into veg room and then out.

Are you running co2?

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No I’m not running co2, there’s fresh air being brought into the room so they’re fine for that. The reason it’s complicated is because of the space I’m working with. The room is about 7.5’ wide x 12’ long x 6.5’ high and I have a 3x3 and 4x4 tent in there. Getting the proper ventilation was tricky with what I was working with

SoCalCraw said:

It’s co


No I’m not running co2, there’s fresh air being brought into the room so they’re fine for that. The reason it’s complicated is because of the space I’m working with. The room is about 7.5’ wide x 12’ long x 6.5’ high and I have a 3x3 and 4x4 tent in there. Getting the proper ventilation was tricky with what I was working with

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Like I say... flow it in through one end and out the other... link the 2 tents together... always vent from flower INTO the veg tent... that way its dryer in the flower tent.

I a really have a chain of 3 tents... flower to flower/ veg to propagation tent then outside. Works really well

SoCalCraw said:

I ran it for the first time overnight and checked my low and high this morning. My low was 65 for night time and high was 73, RH around 30 and I'm halfway through the second week of flower

I THINK WE HAVE FIGURED THIS OUT!!! I was so busy yesterday moving everything around I didn't think to take a video but I will when I get home today!

Click to expand...

Sweet! Glad its sorted man.