Safe to wire ballast like this...?

[jamal-188]

Probably picking up a URI electronic ballast at work this week(got a good deal on one). Anyway, it says it can operate up to 4 bulbs that are no more than 16ft in length. I already have two 6ft tubes but my tank is 7ft, so can I add two 2 foot tubes or will the ballast freak out if it's running different sized tubes? Wouuld I be better running four 3ft or four 4ft tubes?

 

[loganj]

It will operate different size tubes OK. Electronic ballasts are not so picky about the length of the bulbs and I have used Icecap ballasts in a manner similar to what you are talking about...I've even had one ballast running a couple of VHO's and a couple of PC's at the same time. One thing I should mention though...at least in the case of the Icecap ballast...your ballast is probably rated for up to 440 watts total output. With a 2x160w and a 2x75w running, you're pulling 470 watts. Although I expect the ballast would light them all OK, I think it might generate extra heat in the ballast and may also shorten usable bulb life a bit. JMHO.