New Grower Light

[Only]

Hello. Do i need ballast for 70 or 100 w HPS ? I used 90w mhl
In last time (whit no ballast)

 

[woody]

As far as i'm aware all hid lights need a ballast, some can come with a built in ballast but that makes them quite heavy. Try ebay you should pick up for decent money

 

[gone1]

For hps lights you need a really high voltage at the start, far more than 230V or 120V that means that you need a ballast.
Cheers