I'm somewhat new to saltwater and have kept a 4 gallon pico reef for about 2 years with pretty good success. I up graded to a 26 gallon bow front and seem to have more trouble keeping the corals healthy. I change 5 gallons every two weeks and supplement with calcium every few days. i use distilled water to top off the tank to keep the salinity at 1.023. Could it be the light and not the water chemistry? I have a 65 watt PC on the tank. Should I upgrade to a 130 watt PC? Any thoughts are greatly appreciated.