Ceramic Metal Halide bulbs most certainly do not come in just 250 and 400 watt sizes! They come in a wide variety of smaller sizes as well. Many Hydro houses only offer the two bigger sizes for sale because they are classified as a "Retro Fit" bulb - that is, they work with an HPS ballast. Some of the smaller bulbs will only work well on a dedicated, CMH, ballast.
The point I'm trying to make is "Be careful that you're using CMH bulbs and ballasts that are suited for each other". Because all CMH bulbs don't work with HPS ballasts! Some will work, but with poor efficiency!
That's completely true, but an incomplete truth. CMH's under 250 burn on standard
PULSE START Mh ballasts. I was bout to say what you just did T.H. They make the 4k Alto MasterColor in all standard wattages from 50-150, but ONLY PULSE START BALLASTS WILL PUSH THEM. Others roach your lamps slowly but surely, if they even start them at all.
I have a 70w PsMH ballast with a CMH that I don't run because I don't have a capacitor for it and it keeps blowing the breaker (there are only four circuits in my appartment... wonderful) and one 100 cmh that I have waiting for my White Castle and Blue Cheese seeds when they pop. Gonna scrog with a 1.5 sqf screen in a file cab. Oh yeah.
And yes, you CAN let the 70W CMH heat up for a good 45 min and touch it. It wouldn't be pleasant, and you may get skin cancer (lamps kick out LOTS of UVb, good for THC bad for skin cells), but I did it, and it hurt (bout as hot as the exteriour of a cheap black and decker coffee pot cruet), but I didn't get a burn. Won't do it again though.
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