Dinoflagellates

I have recently been battling dinoflagellates in my 120. I am running 500mL of Two Little Fishes NPX Biopellets but I am not dosing a bacteria product. I reduced my photo-period to 5 hours for the metal halides and 7 hours for the T5's. My skimmer has overflowed three times in the past two weeks which dumped nutrients back into the display. I am currently testing the new Vertex Generation 3 skimmer pump on my skimmer instead of the Bubble Blaster 3000, so far the skimmate production is much more stable and is almost twice as much! Surprising for a $70 Vertex pump vs. a $205 Bubble Blaster pump. I covered the tank and turned the lights off for three days and once the lights came back on any algae and dinoflagellates on the rocks were gone! Now, four days later they are slowly coming back. I am now topping my tank off with kalkwasser to bump the pH up and I am giving H2O2 a try. I am going to dose 0.5mL of hydrogen peroxide per 10 gallons of tank water the first two days then bump up the dose to 1mL per 10 gallons. I am hoping this will knock out the dino's within a week. Just to make sure my top off water wasn't adding nutrients to my tank I decided to test it. My tap water has a TDS of 238ppm while my RO water is coming out at 2ppm and my DI is 0ppm. I tested the tank water and the PO4 is 0.05ppm (Hanna checker) but I there is a thread  on Reef2Reef about how even the Hanna checker values are flawed. My fresh RO water tested at 0.04ppm! I would have thought that the RO/DI unit would take out phosphates but I guess not.