Lights/Yields

[Bigpapa]

Let’s see if we can get a discussion going.

I started out in a stealth box under a 300w MarsHydro LED. It wasn’t bad. But obviously, a small stealth box just won’t do the trick. So now I’m into a 4x4x80 tent under 600w MH & HPS. But I’m really struggling with temp control. I have a 4” in-line fan vented to the outside and I’m still dealing with heat stress. I have a fresh air fan pulling anytime the light is on. So much so that I’m thinking about going back to LED. I’m willing to pay for a quality LED if I can get quality yields and dense buds.

So i’d Like to hear from you all about your experience with lights.

Grow well. Be well.

[Obi-Wan]

Is the light vented through a hood reflector or cooltube? How many cfms is your fan? 4” seems like it would be under powered for a 600w hps in a 4x4 tent. Distance to the plants? Temps?

[Chefbjy]

I am growing in a 5x5 with 1000w hps but I have an air cooled hood and 4" inline fan exhaust. I run an oscillating fan inside and I have a 6" box fan blowing air in with a filter in the intake hole. My temps are in the highs of 83f which isn't too bad. I ran an extra intake with some vent tubing trying to draw fresh air in from a window with a filter on the end. If I cool down the room the tent is in down to around 69f the inside of the tent will only get to about 79f. in the hotter part of the day when the room warms up it stays down. Try making the exhaust going out as short as possible. Your intake should be bigger then the exhaust. Great guide to help with temps on gwe.

[DingusKhan]

What Obi-Wan said, and if you can open the vents and cover them with pieces of grow bag to let more air in, that would also help.

I've been flowering with 2 GalaxyHydro 300s and a Roleadro 400w COB in a 2x4 tent. It grows decent weed, I've been pretty happy, but it could be better.

For cooling, I have a 6 inch inline fan stuck straight in the roof vent sucking out when the lights are on with the flaps open, with pieces of reflectix propped up outside to provide light shade. I haven't tried the air-pot idea yet, but I haven't had to. I'm not terribly fastidious on my light-discipline, but haven't had any trouble.

After much "research", cajoling, and hemming and hawing and asking over and over again on different threads, I finally ordered an LEC 315. It seems the perfect balance of the yield of HPS, the frosty/sticky mess of LED, and without the heat. You could get a LEC ballast with a bulb adapter for your current hood, and a bulb for less than $200, and take the glass out of your hood. You could still suck the air out through it for extra cooling. You may as well focus your extraction around your heat source, and keep your balast out of your tent.

Well that's what I would do, in a pinch.

[DrPhoton]

Check my post here on lights. Also perhaps my articles in my signature.

[D.A.A.S.69]

I use a 6inch exaust fan-filter in my tent an it's way smaller than yours, an I use a 315cmh for light, an it never gets over 80degrees in my tent.
I don't think your gonna get a better light than the 600watt

[Waltermelon]

Personally I didn't do well with a 600hps in a 4x4. Now I'm using two 600w (260 true watt) LEDs in a 3x3 and loving it . For extraction I use a c.a.p. 435 (or 475) hooked to the led tent and a tent running a 600w mh also in a 3x3, vented inside the room the tents are. Night time temps here in phx haven't dipped into the 40s in a few weeks and my tents never get above 78° during lights on and hovers around 75°. That's also measured with a min/max thermometer.

[Bigpapa]

It looks like we all do quite a little dance to control heat if we are using HIDs. Has anyone done a comparison doing a full grow under HID and then done another of the same strain under LED and compared the resulting yields?