Alright, wanna give a quick run through of my planned cab before I ask the question. I have a pretty small space for a cab so I think I am going to go with a small cab and try to grow ScrOG style. First off I plan on having 3 chambers in my cab, 1st chamber Im gonna use some fluorescents for the little seedlings, Im thinking 2 dual fixtures, like 4x 15 or 20 watt bulbs, the 2nd chamber is gonna be the biggest chamber with a 150 watt HPS, and the 3rd chamber is going to serve as 2 functions, 1 as a kind of storage chamber for my ballasts, electrics and eventually my odor reducer. 2 as a light dampener from the chamber with the HPS. It is pretty much a cab I found a post on, and of course now I can't find the post or I'd put up a picture. There is going to be a like 100 cfm squirrel blower in the storage chamber kind of serving as the main power behind the ventilation. So, Im gonna use a few 1" pvc 90s in the side of the first chamber, then a like 2" pvc 90 with a bit of 2" pvc routing it around the chamber and ending up somewhere under the screen. So from there I am unsure what to do, I don't have my light yet, might have to order it over the internet as no local store has one in 150watt. So here is my main question would it be enough ventilation if I left the surface of the HPS open, IE: no glass, and routed a 4" flexible hose from one side of the HPS to my storage chamber to complete my all in 1 ventilation system? or should I use glass over the HPS and figure something else out? Like having the air come in through the side of the HPS rather then from the main reflecting surface over the bulb. And also, even if I did that, would it be enough ventilation to keep my box cool? Also what is the benefit of using glass? I gotta do some more checking around see if I can find the main thread for this cabnet. Thanks in advance...