600W HPS Cooling Question

Hello kind people.
I normally run a 400W but have stepped up my game a bit. Heat is an issue now.
I am currently running a 600W Digital HPS surrounded by a 4" Bake-a-round cooltube. The heat is being sucked off the bulb by a DIY Walmart Blower at high CFM's through 4" tubing. Exhaust to outside building. Passive intake vent at low end of flower cab. Ambient temp of basement (which cab is located) is around 72 degrees average this time of year.
Temps are reaching into the 85-87 degree range, while the veg half of my cab is a cool 75 deg.

I have some options, so please help me with your experience.
1. Buy a 6" cooltube and ducting.
2. Add a duct fan to the passive intake to make it active.
3. Buy a stronger CFM fan for the 4" cooltube.

Would the 6" provide much better cooling than a 4" tube? Or would I be better off working with my passive intake?

the size dosnt really matter as much as how much air the fan displaces . I shoot for 1.5-2 x the size of my room displaced every 5 seconds . TBH tho your temps arnt terrible

Thank you!
The fan displaces a lot of air. It definitely creates a strong vacuum to the point where I can feel air getting pulled in through the passive intake hole. When I open the cab doors the temps drop dramatically (to around 7. I suppose then if I add a duct booster fan to the passive intake, I should be able to cool the room much better?
Or should I just run the cooltube exhaust straight through the cab to the outside room?

I use the 600w = 6" 400w = 4" as the minimum for how big your ducting/fans should be. The fan on your 4" cooltube probably isn't enough to cool the 600. You need to get hot air out and cool air in faster. So bigger ducts and a bigger fan?

I run a 600 too and have a 6" 460cfm fan feeding into a splitter which half is my intake at the bottom of my tent and the other half runs through my reflector and back out of the tent. My temps peak around 83 during the first couple of hours of lights on then slowly drops down to 73 by the time the 12 hours on cycle is over as the temps outside the tent drop. (I run my lights overnight)

Hope that's helpful!

How high are the CFM's of that blower?

Schmarmpit said:

Thank you!
The fan displaces a lot of air. It definitely creates a strong vacuum to the point where I can feel air getting pulled in through the passive intake hole. When I open the cab doors the temps drop dramatically (to around 7. I suppose then if I add a duct booster fan to the passive intake, I should be able to cool the room much better?
Or should I just run the cooltube exhaust straight through the cab to the outside room?

Click to expand...

You can get a 6" 252 inline booster fan for like $35 @ Home Depot or Lowes

try fliping a coin at the second its in the air you will know exactly what you should do.

I think hunting down fugit and slapping him around a little bit would be even more helpful!

6" will make a big difference - much higher volume of air will be moved (with a 6" blower obviously). I use a 465cfm for two 430s (Son Agro's), my temps run about 7 degrees above ambient - for me that's anywhere from 55-75 depending on the month. An alternative might be to vent the light from outside the grow room - then you could add CO2 which works better in the 85-90 degree range.

Is your area lined with mylar?

I just put up mylar in my grow area and saw about a 5-10 degree rise in temperatures...just from adding mylar. I think it has to do with the radiant waves being bounced around and such...

But yeah, sounds like you might need bigger cooltube/ducting for that 600 watter.

Doesn't matter, the only thing a "600 specific" reflector would have that a "1000 specific" is a spacer to center the 600's smaller bulb. Hydrofarm sells the spacers if you're worried about getting your light footprint centered up in your reflector

Thanks for the replies folks. I decided to do this one piece at a time and see how it resolves.
I ordered a 6", 400CFM inline that I will start with. I found out that the DIY Stanley blowers are only pulling about 250 true CFM's. With the carbon scrubber attached, it was not enough to cool the 600W.
Hopefully I'll be able to keep my 4" cooltube and ducting, saving me from having to buy the 6" and ducting. I'll let everyone know how it turns out.

Cool. I got 25 ft of 6" ducting at home depot for like $25 bucks so not too pricey if you end up having to replace the ducting. A legit fan could do it though. Will you still be able to use your blower? Then you'd have like 650 cfm rolling through. I'd think even with 4" you'd be good with that much air flow

So the issue turned out to be much less common than I thought. My old 4" ducting was faulty. The most inner layer of plastic film was coming apart from the foil tubing. This created a huge bubble inside the tube that was restricting airflow. Took me a while to figure that one out.

I obviously had to buy some more ducting, so I ordered the 6" just to be safe. This has my closet nice and cool now.

Thanks for the help everyone!

Excellent!