ADVICE PLEASE

im currently growing 1 plant under a 600w hps but is switcable to 400w my temps are sitting at about 35 degrees under 600w and under 400w about 30 which I no is more of an acceptable temp would it make much difference running it on 400 instead of 600w? I have a cooltube and everything but cant use it incase neigbours hear the 6" fan so just running the 4"

By rights a 6 inch fan running at reduced speed should be quieter than the 4 inch. So getting a fan speed controller could solve this.

I believe eBay could be your friend here...

You could always build a box to put the fan in to reduce noise too.

Try and run the full 600w even if it means a littlevextra cash and or time invested now

Plants need twice as much light when they flower as when they were vegging. So if you veg under 600 and go down to 400. You are going to see a yield decrease.

Fan controller would work but degrade the life of your fan. Can Fan makes a max-fan pro 6 and 8'. I can attest to both, quietest, strongest, most energy efficient truly three way adjustable speeds. They don't restrict the motor its an actual three speed.

hang the fan from bungee cords and turn a radio to rap and push it up against the wall. then you can plug the radio into your timmer.