Im going to go ahead and blow a myth about croceas... as far as light goes, they really dont need all that much. PAR meter in hand, I have been doing surveys of the light levels in most people's tanks, and although many tanks may be considered 'high light' the clams are placed at the bottom, or off in a corner, where their light levels are only in the PAR ranges of 100-120! And they look very nice, colored in, and happy.
I think that our standards have changed over the years, and at one time, the light levels we may have needed just to get by were pretty high, but since then, reflector technology has vastly improved, bulb outputs have improved, etc... yet our 'idealogy' of what wattages and sorts of lights we need hasnt. 8 years ago, a 250wattSE halide 10,000K Ushio with a flat reflector and a couple VHO actinics, or even PC actinics was the norm... and now, a couple 150wattDE 10,000Ks with two strips of T5 bulbs, all in decent reflectors, can produce just as much light, sometimes more.
While Croceas are some of the most tolerant of high light (Dana Riddle's experiments have shown us that), that doesnt mean they need it.
Look at these two examples, and the light levels I recorded... and the croceas have been happy as can be...
Look at em... croceas in the 100-120 range... and looking pretty!
You might need a little more than what you have, but I wouldnt worry too much, or get too drastic. Perhaps simply switching from PC to T5s would be a good idea... switching from PC to T5 should pay for itself in a couple years in your case... lower running costs, lower electric, lower bulb replacement costs/longer bulb life.
