Run a Sun Blaze 6 bulb T5 with only 4 bulbs? 2 bulbs?

Hey everyone,
I just bought a Sun Blaze 4-ft, 6-bulb HO T5 light fixture. It'll be for a mom/clone/veg/seedling space i'm setting up. My question is, would it be bad to run this unit with only 4 bulbs installed? Or only 2 bulbs? I called Sunlight Supply, and their tech said he THOUGHT the 6-bulb unit had two internal ballasts, one 2-bulb ballast, and one 4-bulb ballast. He said if I take out one of the bulbs that is fired by the 2-bulb ballast, the other wouldn't fire, and I'd be left with 4 bulbs firing. Or I could take out one of the bulbs run by the 4-bulb ballast, and the other three wouldn't fire, leaving me with 2 bulbs firing.

That doesn't seem to be the case. The unit actually fires any combination of 1-6 bulbs, in any arrangement. I just want to make sure it wouldn't be bad (or unsafe) to use this unit with either 2 or 4 bulbs when I don't need all 6? I wish I could have gotten a better answer from their tech, but such is life.

I emailed Sun Blaze last week on this exact question but still have not gotten a response yet. I did hear back from another RUI user who does it and has had no problems. If I get an email back from them, I will let you know.
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I just called a couple different Sunlight Supply distribution centers until I got a guy on the phone who sounded confident and knowledgeable. He said that it is not a problem to run my 6-bulb unit with only 2 or 4 bulbs in it, in fact he had one at home running that way as we spoke (or so he said). I didn't ask him about only running one bulb, but I don't think I'll ever have reason for that.

So there you go. The answer is yes, run it with 2, run it with 4, run it with 6, doesn't matter. Just don't fiddle with the empty sockets - they still have power to them.

P.S. - The 6-bulb unit only has ONE ballast capable of running up to 6 bulbs. The bulbs are wired in PARALLEL, which is what makes that work.

While I'm thinking of it... My only complaint about this unit is the hanging hardware. As it is, the wire cable hangers waste about 13 inches of vertical space. BUT, I noticed that the wire cables are held in place by some fittings with standard threads. You can just unscrew them and replace with a threaded eyelet from the hardware store. Suddenly I have 13 extra inches of vertical space, meaning I can build my veg cabinet 13 inches shorter. Sweet....

I run my at 2 and 4 bulbs all the time. Just make sure you take the bulbs completely out cause if you leve them in but just twist them to the off position for some reason the still seem to get a little current and actually will burn out sometimes. Figured that out the hardway. No biggie though, the bulbs are cheap.

We have two of the 8 bulb T5HO's. One is perfect. The other, well, they cant seem to take bulbs and turn the socket on two of them so it runs without them in at all. Been fine for many months now. I hate the turn socket system. Very fragile and unreliable.

yes. they are correct. what you should do ( if you want to make the fixture better and know how to wire things) is add 2 switches and 2 separate power cables to the ballasts.

mine has 2 switchs so for 12 hours its 10000 lumens(2 bulbs left on 24/0) then for the other 12 is has 30000 lumens(4 bulbs switch put in 12/12)

Completely fine to do this. One of the great features of the Sun Blaze

I just got an email from them and they say they are designed for all of the tubes but they will work with some missing. He than said that with the missing tubes, the ballast and/or tubes may fail at anytime. I didn't get any specifics on why but that was from the manufacture directly. I am sure they would like to sell more units instead of marketing that their fixtures can be used in that way. I think your right on this Bluntcuts but I am going to try to get ahold of a friend of mine who is an electrician to ask.
Things to consider
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edit... I think I have a different fixtures than you Blunt... The ones I am specifically talking about our the Sunleave fixtures. Not sure if there really is a different but I want to be clear in the post