Looking for feedback, Vodka / Carbon Dosing, Big Tank, Big Nitrates

[MrNaso]

I have a 500 gallon + system,mixed reef with fish,feed heavy.I have used nitra-guard bio-cubes titanium for 3 years and my Nitrates stay in the area of .30
phosphates .05 or less.I also run two large skimmers.
Great product add approx 250ml a month to replace what has been used up.

[LifeIsGreat]

I'm not an expert by any means, I probably know less than you, but have a look at some of the discussion regarding sand bed depth. Unless you regularly vacuum out that shallow bed all the way to the glass, that sand might be saturated to the point where it can't consume any more bad stuff. That may be where your high numbers are coming from.