From all I've read you definately need more aireflow than your current fan. 265cfm seems to be the "norm" for 400 watt systems.
pastor420 Reviewed by pastor420 on . Heat problems What's the best way to deal with heat? I added my 400watt hps yesterday and my cab shot up to 90. The ballast is outside so it's all the light that's making the heat. So what's the everyone's opinion? Cool tube or new exhaust fan? The fan I have in there now I think is under 100cfm it's more like 60 probably. So I found a 265cfm dayton at my local hydro shop I'm thinking of getting. My cab is 4x4x2 so that fan would exhaust the air over 8 times a minute. The new fan would be about half Rating: 5