I'm not sure what your budget is, but there are inexpensive multi-chip lights you can buy that come in 10, 20, 30, 50, and 100w versions with color spectrums for reef tanks. Rule of thumb for you; 10k spectrum will give you the most growth, but something in the 455-460nm range will give your corals color vibrance. With the multi-chip LEDs, you can mix and match to give both and it won't cost you an arm and a leg. You could even do a 14k spectrum 50w and I am betting that will suffice your 35 gallon setup. You can get that kit for around $50-75 which will include heatsink, cooling fan, driver and 90 degree optics. Optics are easy to understand. Think of a 90 degree bend, the joining point would be your LED and the angle the lines go in would be your spread. Bigger number, bigger spread, with decreased intensity. Smaller number, smaller spread with increased intensity. You can search them on Ebay. I have researched them extensively and seen some of the nicest sps and mixed reefs I've ever seen, using them. Don't let people scare you eith "you get what you pay for". For $50, I can replace that unit every year if needed, and still match what they paid over 10yrs. Luckily, they most likely WON'T break once a year, and you come out very far ahead. Multi-chips are the LED future IMO. Google led ac-rc and browse your options! Good luck!