View Full Version : 250w HPS Opinions needed :)

09-10-2009, 12:47 PM
Hi everyone,

I have another question as I near flowering for some of my garden. I am looking into purchasing a 250w HPS setup, and once again I will be using BGH. I need some comments about the current 250w HPS you have and some of the advantages and disadvantages you have with using it. Specifically, I am interested in the size of your area it flowers/fruits, and how easy or hard you find it to keep the lamp cool(also if you have an exhaust fan hooked into the system)..

I am very new to the gardening so any tips or comments you have about how I should choose the specific ballast, and reflector will be greatly appreciated. This will be used in a grow room(4'11" x 4'11" x 6'7").

I do not currently have any great ideas on how much ventilation is need for an exhaust fan in this setup(formula seems a bit tricky to me). Also, if I use an Exhaust fan I would assume that would create an intake on the other side of the room through the OPEN vent??

Thanks again,

David G.
09-10-2009, 11:38 PM
First of all, are you planning on utilizing the entire 4'11" grow space? If so, a 250W HPS is too small. You would need at least a 600W to cover this area, and many growers even opt to use a 1000W in this size space. So before I answer your questions regarding the 250W system, let me know how much space you will actually be needing to illuminate.

09-11-2009, 10:27 AM
Hi David,

I knew 250w was way to small. Actually from looking at things I decided I would try a 400w light instead. A 600w seems like it may be a little to pricey for my monthly usage bills. I would only use about 3x3 area of that space, never exceeding 4' in height to allow for the 18"-24" space to hang the light above the plants as heat burn would seem to be an issue.

My main questions are what size fan would properly vent the space? I am considering a 246CFM(its the second smallest Dayton you offer). Would it have to run constantly and what wattage would that fan use?

Also, in using the Dayton exhaust fan would that cool the light and vent the room at the same time, bringing fresh air from the intake side? If so, that would help me utilize one fan producing good results I would hope.


David G.
09-15-2009, 10:49 PM
The Dayton would certainly provide the CFM you need to vent that size area. However, if it's within your budget, I would recommend you go with a centrifugal fan instead, like the CAN 4":

The main reason I would recommend this type of fan is that if you decide to add a carbon filter later on, you will have more options and better results with a centrifugal fan. In addition, centrifugal fans offer higher static pressure, meaning they can push more air, especially through devices such as carbon filter, without losing too much velocity (or CFM). Although the Dayton shows a higher CFM, it's only showing you free air movement. As soon as you attach ducting, or a carbon filter, etc. that CFM goes down quickly.

In addition, centrifugal fans use less electricity, are quieter, and are easier to attach ducting to. If you don't plan on ever needing a carbon filter, you are on a budget, and you don't mind the added noise, then the Dayton should work out fine for you.

09-17-2009, 01:07 PM
Thanks again for a great post David. I will be going with a Can-Fan and adding a carbon filter later.