400 watt CMH with old magnetic ballast

hillbill said:

I ran those CMH bulbs for years and they need standard hps magnetic ballast and are most definitely Open Rated. 400w much more efficient than the 250w. Best results used with hps. Beautiful light and very happy plants and excellent trich and terps development.
Just never seemed to make buds tighten up. I still have bulbs, some are new.

All COBs and white or white/red led panels these days.

Didn’t realize post was ancient!

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Renfro said:

That was just a MH conversion bulb in the old post. Not a CMH. To my knowledge nobody is selling a 400 w CMH conversion bulb yet. @GoBrah may have some answers as his company was working on some.

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