Phosphates in RODI water?

I'm having abit of a battle with Cyano, and thought I should check the phosphate level in my RO water. I recently changed all the filters and the DI resin, and wasn't sure what the level would be.

Using a Hanna Colorimeter, my RO water tests at .04 mg/l. Level in the tank is running around .05, with a fluidized reactor running Rowaphos. I kinda thought that the RO would test at 0.

Any thoughts on if that level is high for my topoff water?