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[Snow Crash]

Heat problems.
I have been growing since 1994, started outdoors, and worked my way indoors.
Most of the indoor growing I have done were with Grolux fluorescents, then eventually switched to T5s, which I still use with decent results every time.
Recently I have been doing some experimental grows, looking for a more efficient ways. I bought a small HPS light, and a 90 watt LED, and a hydro setup,
just to see how they work. I have been trying so many things to keep the 250 watt HPS cool enough to operate, and 93 F was the best I could come up with.
I have this in a 20" X 24" X 49" cabinet (with a separate cabinet above for ducting and the ballast) I have plenty of 44 cfm pc fans in there, and an 80 CFM
inline duct fan (which the hydro store recommended to use with a 250 watt HPS with a Supernova reflector) hooked up to it, and I have a 44 CFM fan as an
intake. The best temps I got was 93 after I removed the tempered glass, with the ambient temps outside the cabinet about 63 F. Is it because the Supernova
reflector is no good? Do I need bigger than the 80 CFM duct fan to cool it?

I know 1+ gram per watt is possible with HPS, I have seen it done. It should be relatively easy with strains yielding 900 m2, once you have everything dialed
in. I am getting .7 gpw with my T5s. which is good I guess, but if 1+ is available, I'd prefer that, which is why I'm looking toward HPS. Once I get all the HPS
stuff figured out with the 250 watt, I want to get maybe 2 or 3 600 watt lamps.

That is kinda crazy. You have an area not much larger than 16cuft (if that much), and you're running an 80cuft fan... so that entire cabinet should be exhausted at least every 15 seconds. The crazier part is that the intake temperature is a cool 63 degrees.

So get that. You pull in enough 63 degree air every 15 seconds to completely exchange all of the heat. Yet somehow this air is being super heated to 90 degrees plus? In 15 seconds?

Something is very fishy. Either you have a lot of 90 degree turns in the ducting reducing the ventilation capacity or you are taking your temperatures from within the "bubble of heat" that is cast by the HPS bulb. A 250w bulb should be kept around 8" or so from the top of the plants. More than 2 feet away and you are wasting energy.

Place your hand beneath the bulb and get an idea of where the "bubble of heat" extends to from the bulb. Try to mount your ducting so it is pulling in the hot air right near the ballast at the top of the cab. Then start taking your temperature readings in a shadier part of the cab maybe beneath a leaf or two near the top of your canopy.

You have adequate ventilation for your space and your intake temperatures are plenty low. Something else is going on. Check out the placement of your thermostat and minimize any crimps or turns in your ducting that you can.

 

[Encomium]

...my plan tap water is 140 ppm(ran out of bottled RO water, gets expensive without a RO system) and i added about 180 ppms of nutes to each...ive learned that if the h20 and ppms go down evenly then thats ideal. if the ppms go down and not so much water then its eating everything it can get ahold of and you can feed em more and same for the opposite. if water goes down and not so much the ppms then you are over feeding and it has plenty of nutes in storage in the plant so i need to feed less...thats how ive been feeding. each strain will be different eventually and i will only know what to feed by the ppms in the res.. is this correct or am i somewhere in left field.

You might want to get a water quality check in your city/house. My tapwater is roughly 140 ppm and I've opted to just use that instead of the RO or Distilled water I'd been buying and I've not had any issues so far (going on 2 weeks now). Key parts you'll want to look for in the report is calcium levels (100-150 mg/liter is acceptable for MJ) and Magnesium. I just use the old gallon jugs I had from buying distilled water and fill em up with tapwater and let them sit for 24 hours before using them.

Oh, and giving nutes to seedlings isn't needed since the aril (seed coating) supplies plenty of nutrients for the plants to develop in their infancy. Giving nutes prior to this may stall growth according to Cervantes' Bible.

 

[Encomium]

That is kinda crazy. You have an area not much larger than 16cuft (if that much), and you're running an 80cuft fan... so that entire cabinet should be exhausted at least every 15 seconds. The crazier part is that the intake temperature is a cool 63 degrees.

So get that. You pull in enough 63 degree air every 15 seconds to completely exchange all of the heat. Yet somehow this air is being super heated to 90 degrees plus? In 15 seconds?

Something is very fishy. Either you have a lot of 90 degree turns in the ducting reducing the ventilation capacity or you are taking your temperatures from within the "bubble of heat" that is cast by the HPS bulb. A 250w bulb should be kept around 8" or so from the top of the plants. More than 2 feet away and you are wasting energy.

Place your hand beneath the bulb and get an idea of where the "bubble of heat" extends to from the bulb. Try to mount your ducting so it is pulling in the hot air right near the ballast at the top of the cab. Then start taking your temperature readings in a shadier part of the cab maybe beneath a leaf or two near the top of your canopy.

You have adequate ventilation for your space and your intake temperatures are plenty low. Something else is going on. Check out the placement of your thermostat and minimize any crimps or turns in your ducting that you can.

Only thing I can think of is *where* he's taking his temperature readings from... I mean, if he's taking his temps say right below the lamp then his temps are going to be quite high yet not an accurate reflection of his canopy temp.

 

[cervezacorona]

That is kinda crazy. You have an area not much larger than 16cuft (if that much), and you're running an 80cuft fan... so that entire cabinet should be exhausted at least every 15 seconds. The crazier part is that the intake temperature is a cool 63 degrees.

So get that. You pull in enough 63 degree air every 15 seconds to completely exchange all of the heat. Yet somehow this air is being super heated to 90 degrees plus? In 15 seconds?

Something is very fishy. Either you have a lot of 90 degree turns in the ducting reducing the ventilation capacity or you are taking your temperatures from within the "bubble of heat" that is cast by the HPS bulb. A 250w bulb should be kept around 8" or so from the top of the plants. More than 2 feet away and you are wasting energy.

Place your hand beneath the bulb and get an idea of where the "bubble of heat" extends to from the bulb. Try to mount your ducting so it is pulling in the hot air right near the ballast at the top of the cab. Then start taking your temperature readings in a shadier part of the cab maybe beneath a leaf or two near the top of your canopy.

You have adequate ventilation for your space and your intake temperatures are plenty low. Something else is going on. Check out the placement of your thermostat and minimize any crimps or turns in your ducting that you can.

Thanks for the quick response.
The math doesn't quite work out for me either, especially with an ambient temp of 63 outside actively being brought in @ 44 CFM into the cab. I'd hate to see
the temps when the outside temps exceed 70 F....
My ducting is actually extremely straight, no turns except one @ maybe 15 degrees.
I had the digital thermometer 12" directly beneath the bulb when I took the temp, and it was too high, it got hot really fast, I shut it down when it got to 100 F.
I tried moving the thermometer around, and it is usually 3 F less everywhere else @ 12". 8 inches would be ideal with the reflector I have to maximize lumens.
I even tried removing my light traps, and in addition to giant light leaks, the temps stayed the same, I checked my intakes, and felt the air going through, so it wasn't
that. I even put a 10" fan in there, a regular 3 speed fan. Only when it was on high, I got it down to 93 F. I also tried reversing the duct fan, so it brings in fresh air,
through the hood, it actually got hotter.
I never had issues venting my T5 grow, with lights on, and ventilation off, it gets to 90 F at worst, with the ventilation on, it is 79 F at most, usually 77 F.
Right now I am guessing I either have defective duct fan, or a defective HPS system. I may be wrong though. I'd really hate to buy a 170 CFM fan just too cool off a small
cabinet with a 250 watt light. That is just too much, an 80 watt fan to cool a 250 watt light.
I haven't started any plants under this setup yet, not until I have the temps below 90 F. Ideally under 80 F. When I do, it will be a hydro setup, that will be a first for me too.
I'll see if I can take some pics of my cab, so you can get a better visual of my setup. It feels kind of weird asking for advise, usually I'm the one to offer advise. I guess no matter
how much one knows, there is always more to learn. I hope my hydro setup wont give me issues like this light is, I hear it is actually pretty easy.

 

[cervezacorona]

Only thing I can think of is *where* he's taking his temperature readings from... I mean, if he's taking his temps say right below the lamp then his temps are going to be quite high yet not an accurate reflection of his canopy temp.

I took the temps where the top of the canopy would be, if there were plants in there. I'm waiting on the plants until I get the temps dialed in.
My temps were 3 F less as I moved the thermometer closer to the edges of the cab. Still too high.

 

[Snow Crash]

An option for you might be to include a small desk fan pointed upwards at the bottom of the cab.
This should help the air circulation in the small cabinet.

I think maybe something you could try is to use a good deal of smoke and with all the ventilation on blow the smoke into the intake ports and watch what it does. It could be the air flow is doing a kind of reverse waterfall thing where the cool air is getting pulled right out before it has an effect on the ambient heat in the cabinet.

The temperatures should definitely be lower with the setup so check the air flow and maybe reposition the fans if need be. A little air circulation will go a long way towards assisting with that.

 

[cervezacorona]

An option for you might be to include a small desk fan pointed upwards at the bottom of the cab.
This should help the air circulation in the small cabinet.

I think maybe something you could try is to use a good deal of smoke and with all the ventilation on blow the smoke into the intake ports and watch what it does. It could be the air flow is doing a kind of reverse waterfall thing where the cool air is getting pulled right out before it has an effect on the ambient heat in the cabinet.

The temperatures should definitely be lower with the setup so check the air flow and maybe reposition the fans if need be. A little air circulation will go a long way towards assisting with that.

I will try the smoke thing, see where it goes. This whole thing is pretty weird. I have seen multiple hoods with larger lights cooled with one duct fan, and temps were lower than mine.
I'd add some more fans, but all the ones I have are in use, and the ones that aren't are too big. The one 3 speed I tried left little room for other stuff, and just blew hot air around.

I wish I would have bought the 6" cooltube instead, and used a 6" duct fan, I'd be into the 2nd week of my grow already by now. I have a feeling that maybe the SuperNova hood is
at least a small part to blame, the included ports on the hood are lame at best. One is okay, but the 2nd is mostly blocked by reflective material. I tried removing the lens, so it could
suck the air better, but that didn't work, it did get the air out a little faster, but the bulb was not behind the lens, and added heat anyways. When I get my 2-3 600 watt setup, I will
definitely use cooltubes, and high power inline fans, I'm looking to do this later this year, as funding permits.

 

[DaHighLife]

complete newb question.

im about to start my first grow and i was wondering what would be a better place to do the grow. I have a small bathroom that can be used just for growing or i have a decent size closet. Im planning on growing about 4 decent size plants. I just want to know if there is really any difference. thanks

 

[Pjloudpack]

Ok ireally need help. One of my plants leaves are turning purple. The oldest are turning yellow. I think its nute burn. Can somebody plz help me cuz its my first grow and I don't wanna mess up. Plz inbox me with the advice plz

 

[Snow Crash]

complete newb question.

im about to start my first grow and i was wondering what would be a better place to do the grow. I have a small bathroom that can be used just for growing or i have a decent size closet. Im planning on growing about 4 decent size plants. I just want to know if there is really any difference. thanks

I'm partial to the bathtub/shower situation in the bathroom, especially if there is a ventilation fan installed. It makes managing run off a lot easier. Just be careful with your heat and humidity in there, and make sure you bleach every crevice of it to kill any molds already living in there.

Ok ireally need help. One of my plants leaves are turning purple. The oldest are turning yellow. I think its nute burn. Can somebody plz help me cuz its my first grow and I don't wanna mess up. Plz inbox me with the advice plz

It is probably just fine if you are more than 5 weeks into flowering.

 

[Dougiefresh2011]

I have a question. Not my first grow but still a newbie. I did change where my set up is. Its an attic grow for stealth reasons. It gets really hot in my attic sometimes 90 or more. 600 watt light also dim-able, 6 plants under. 425cfm fan along with a/c blowing in tent 3x3x6 along with one osculating and two other small fans. Temps get as high as 80 to 89 during the day. Should I try to maybe vent out some of the hot air from the attic? I don't know just thought maybe you guys had some advice for an attic grow. It gets hot as hell up there. What to I do? I don't want to bring the brightness down on my light at all. I want to keep the 600 watts going for the 12/12 cycle. 4th week of flower so I'm thinking it will only get hotter as the buds grow.

 

[cervezacorona]

An option for you might be to include a small desk fan pointed upwards at the bottom of the cab.
This should help the air circulation in the small cabinet.

I think maybe something you could try is to use a good deal of smoke and with all the ventilation on blow the smoke into the intake ports and watch what it does. It could be the air flow is doing a kind of reverse waterfall thing where the cool air is getting pulled right out before it has an effect on the ambient heat in the cabinet.

The temperatures should definitely be lower with the setup so check the air flow and maybe reposition the fans if need be. A little air circulation will go a long way towards assisting with that.

I tried the smoke thing. It drew the smoke right into the cab, and blew it out where it is supposed to.
I am trying something different, I connected the duct fan directly to the flange, and I left the 2nd vent on the hood completely uncovered. The duct fan sucks the air from the hood and the cab, and blows
it into the upper cab with the ballast. The air is directed right at the ballast. And there are 2 good sized passive vents, about 4 1/2" each. If this doesn't work, maybe it wans't meant to be.

 

[Pjloudpack]

Its my 5th week into vegging. The younger plant in stunted no doubt about it. But the plant that's five weeks the leaves that are the three fanned are starting to turn yellow. Any help? Also both plants are starting to have growth in between the limbs and stem. What does this mean?

 

[Dougiefresh2011]

you need nutes bro probably N. The growth in between the fan leaves are where you would get your clones from once it has vegged long enough. I may be wrong but I do be leave that is what is going on.

 

[Dougiefresh2011]

Can some one tell me what the hell popcorn weed is?? Is that an actual strain or is that just a nick name for mid-grade??

 

[cervezacorona]

Can some one tell me what the hell popcorn weed is?? Is that an actual strain or is that just a nick name for mid-grade??

Those are the little buds towards the bottom of the plants where not too much light reaches. At least that's what I always thought that was.

 

[Dougiefresh2011]

already!! You know what thats sounds about right. If any one else has any thing to say I would like to know. thanks though.

 

[Pjloudpack]

Thats the thing I fed it half strength nutrients sunday. I gave it bc boost and grow, magical,sugar daddy and thrive alive b-1 red. What can I add to cover the nitrogen def.?

 

[Dougiefresh2011]

Me personally I like fox farms nutes but that shit is expensive. But I have never had a prob with yellow leaves with big blooms and tiger blooms. Maybe one of the more experienced growers can let you know something I dont know. To me though fox farm nutes are worth it.

 

[Snow Crash]

Thats the thing I fed it half strength nutrients sunday. I gave it bc boost and grow, magical,sugar daddy and thrive alive b-1 red. What can I add to cover the nitrogen def.?

For starters... More than 1/2 strength... and then from there you should know that the remedy is going to take time. It isn't like a hunger pain where you feel hungry, eat, and now you're not hungry anymore. Give her time to recover and just keep an eye on the new growth. If the problem seems to worsen then post some more pictures and we can go from there.

Time though. time.