Halogens are not even an option. NEITHER is adding just NO fluorescents. Forget about it.... Also, halogens aren't anything at all like halides.
Additionally, your PCs are, no offense intended, crap compared to T5's and or Halides. Generally speaking, trying to give you something you can wrap your head around. Lighting goes like this, from least powerful, to most powerful.
Normal Output fluorescent
Compact fluorescent
VHO fluorescent
T5 fluorescent
MH... (High intensity discharge)
Now there are too many different factors that come into play as far as exactly how effective these individual types of lamps are. Too many for me to describe here, if you want to understand it all fully, do some thread digging here, you'll find weeks, or months worth of articles to read on lighting. However, there's no cheap way out. Either do it right, or don't keep things that need that much light. Your PC fixture really is just good for softies. Now there are a lot of softies you can have under that and you can keep a beautiful tank, no doubt. But that sebae ain't going to be healthy. It needs more... Don't waste you money on another PC fixture. I suggested what I feel was the best option for your situation. That would have your tank and your pocket book at heart, If you still believe you can get by some other way, or would like to try the halides go right ahead. But your PC lights is crap in comparison to what a pair of OVERDRIVEN INDIVIDUALLY REFLECTED T5HO'S will do....no doubt. I believe that with 4 over driven, good PAR producing T5's and 2 of your 65w PCs as actinic supplement, you'll be able to keep ANYTHING. Which is why I said you might replace later. It's a cheap upgrade later on. Of course you definitely could go with metal halides.
But the cost is going to be significantly more. you would need at minimum 2, 175w MH jobbers to get enough light. you can't add 70 watters then change to 175 watters either. Also I would recommend actually doing 250 watt. For depth penetration. So.... anyways, I feel the icecap T5 retro is your best option.
