NyteGTI
Aquarium Advice FINatic
also check ebay for the LEDs. if you don't care about sunrise & sunset features & just want dimmable units the 2 Ebay LED fixtures are being used perfectly over a 4ft tank by many people. There's also Eshine LEDs that have their own controller. but unless you can get a bunch of friends together to order multiple units(8+) the shipping will put you out of your 500$ price point for s 48x3W fixtures