5 inch 400 cfm (680 m3/h) fan for 600w HPS tent

Hey there,

Quick question for those with experience: I was told by the guy at the shop that a kit that I bought would be the best and would work well - this all ended up costing nearly twice what their entry level 600w kits do.

He gave me a 125mm Prima Klima EC/ TC fan to go with DR120 tent and 600w HPS w/ Dutch barn style reflector. This is now setup and venting outdoors with good intake into the room; I put another direct intake in yesterday and have had windows and doors open so there is lots of passive airflow.

Ambient temps in the room are 17 degrees C (62 F) and temps in the tent have not dropped below 28 (82F) - going up as far as 32 (90F). So it looks like this fan can only keep within 13C/ 20-28F of ambient.

The fan has a temperature-based controller which causes it to go on full a lot of the time (which looks like using another 170watts from manufacturers site- so nearly 800w total). And its very loud in the room (not too bad outside - it is a nice fan). My main brief to the guy at the shop is that this setup should be quiet.

The guy at the shop is telling me that this fan should have no problem keeping the temp down well below where it is now; he's saying this is unusual. Also he's saying that 5 inch/ 125mm is fine for this - that its the same motor etc just a different flange. The airflow for a 6inch would be 1100 m3/h/ 648 CFH but I have installed 5 inch ducting so changing this would be a huge amount of hassle.

So I have a few questions:

1) Seems like 5 inch fans are unusual - should it have been ok with this or should he have given me 6 inch? Should I still be looking at 6 inch?
2)does everything else with this sound as you'd expect - this is all normal when it comes to tents/ HPS or are my temp ranges still out of kilter?
2)Is the easiest solution to this to get an air cooled reflector?

Wold appreciate any thoughts or experience you might have with this.

Thanks,

1st lesson: Do your homework and be wary of shop dudes trying to sell you the Moon.

Their air cooled kit was more expensive - I think he was trying to help me!

My question though is whether I could expect this challenge with 6 inch fan also - i.e. the 5 inch is ok and I need to get the air cooled filter. From the research I've done heat can also be a challenge with 6 inch fans and AC reflector is almost required with a tent.

You could buy an 8" fan and fan controller then dial it down. I'm using an 8" S & P fan dialled right down in a 1.2 x 1.2 tent with a 600w HPS. It's extremely quiet and now the hot summer has gone temps don't go above 28.5c. As we go in to winter tent will sit at 26c. Will be buying a AC unit or switching to LED for next summer. The humidity and temperatures at night in the UK have been ridiculous these last few years.

Thanks RudeDog. I'm in the same climate as you btw and my temps are a couple of degrees more so looks like I'm not too far off what you're getting in terms of temps, although the noise is significant once you're actually in the room.

Tbh there is so much hassle (and expense) involved in setting up new ducting/ buying new kit that AC reflector is better option.

The fan and room conditions you specify both sound like they should work. My question is, where in the tent vertically are your intake and exhaust? Ideally your intake should be at floor level and your exhaust should be at the ceiling and a circulation fan should also be in use.

Hey bs0 thanks for the response! Intake is as floor level and working as expected - these tents are amazing (there were none available the last time I grew). The outtake is at the top of the tent and I have a nice little secret Jardin circulation fan. I’ve been dialling in the environment more, the fan actually needs to be set low for recommended air turnover and is super quiet. When the fan was roaring and temps wouldn’t drop it was actually a bit traumatic! All is different now - I dialled down the light to 400w (dimmable ballast) and it’s a nice place to be - 28 degrees c.

I pulled the trigger on an air cooled reflector - 6 inch which I have reduced down to 5 and will be installing there shortly.
One of the guys at the shop was saying I’d really want a separate vent and fan for the light but I really don’t want to spend any more or have to drill a third vent into the room!

from research it looks like running existing fan and vent for the AC light also should be enough to bring the temps down- hopefully up to 5 degrees c. I’ll be putting the fan in front of the light and blowing through.

It should work pretty well to have carbon scrubber>reflector hood>exhaust, especially if the scrubber is mounted in the upper portion of the tent. You should be able to run a 600 air cooled in 3x3 pretty easily. IMO best case for tents is how simple odor management is, properly vented/scrubbed tent will never make the slightest bit of smell.
20 degree+ break between the interior of the tent and the ambient outside is strange. Hopefully there isn't something else going on.
Grow on!