Dimmable ballast Question.

Anyone know from experience if its ok to adjust a dimmable ballast from say 600w down to 400w, or vice versa when the light is on, and has been running for several hours? Or is that not good for the bulb?

Thanks.

hey bigboy don't dim down your lights while they are on, i did it once blew up a 400w hps across 4 plants 6 weeks into flower... NOT FUN
wait untill your lights are off if your gonna dim it

I agree! Better to turn them off first. Then change the setting and wait 10 minutes before turning back on.

I have yet to know how to dim my dimmable ballast...so...I have no idea..lol

missnu said:

I have yet to know how to dim my dimmable ballast...so...I have no idea..lol

Click to expand...

I've had the Lumatek ones for a while and I never dimmed them until recently. I called Lumatek and asked them and also talked to some people on RIU. Something cool that I found out from talking to the guy at Lumatek and to technical support at Hortilux was that you should not run a a bulb on a dimmed setting. If you are going to dim your ballast then change the bulb for an equivalent wattage. Running a 1000w bulb dimmed to 600w actually changes the spectrum of the light.

^ That makes sense but in my case I have dimmable 600w, I shouldnt turn it down to 400w unless I use a 400w bulb?

When I bought a veg bulb the guy said they dont usuallymake 600w MH bulbs unless its a "conversion" bulb. So a 400w MH would've worked the whole time?

Hey guys.. Thanks for all the replies! It was kind of what I thought.. Figured it couldn't be good on the bulb, but would have used it as a last means of temp control if I had to.. Would have been cool to be able to just switch it at will without having to worry about shutting it down, and cooling it first.

Thanks again.

missnu said:

I have yet to know how to dim my dimmable ballast...so...I have no idea..lol

Click to expand...

Mine is straight forward.. There is a knob on the side that turns, that says 600/400/250..

weksos said:

^ That makes sense but in my case I have dimmable 600w, I shouldnt turn it down to 400w unless I use a 400w bulb?

When I bought a veg bulb the guy said they dont usuallymake 600w MH bulbs unless its a "conversion" bulb. So a 400w MH would've worked the whole time?

Click to expand...

I thnk the idea is that you can use the 600w bulb but you will change the spectrum slightly if you do run it dimmed to 400w and thus you make it less efficient. How much? I really can't say but I imagine not a ton. Not sure why he told you that about 600w bulbs. All the manufacturers make 600w MH bulbs.

Ive done and reading a few months go on this because I plan to go with one. If you overmatch the bulb compared to the ballast the result will be as you guys have said a modified spectrum. You also significantly reduce the lifespan of the bulb. Don't quote me but its something like a quarter of the lights life. That'd significant to me. And depending on the quality of the ballast, well I don't think it will affect the ballast significantly as im sure it's not getting an electric kick back.Just my two cents, oh and its not hard to all to find a 600 of even a 1000 watt bulb as Philip he mentioned.

i was told by hydrofarm to let it run for a hour to get the bulb fully warmed up,then if u want to dim it u could dim down,starting out a 600 at 300 will never let the bulb fully get warmed up causing ur bulb to die very fast.i use those 50dollar bulb for dimming and the 100 dollar bulb when i am ready to run at full power and its seems to work for me.running a phantom and lumatek

your bulb will warm up then dim down^

I just started running a 600w digital ballast with a 600w mh cov bulb dim down to 300w, so this thread is very interesting.