I'm dosing 90cc/day on my 1200 gallon system. Nitrates are 4.4. I don't see much of a reduction in phosphate and still have to run GFO. My nitrates were in the mid-20's after stopping vodka dosing for 45 days while my skimmer was offline for a week, then I decided to re-start to get the nitrate down.
As an experiment since my nitrates were coming down so well, I took my GFO offline and it climbed from 0.03 to 0.11 within a weeks time. So, I think the vodka works good for nitrate, but not so much for phosphate. I have been dosing 80-90cc/day for quite some time now and my nitrates are staying right at 4.4, so I am just maintaining at this point with the current dose.
It looks like skimmate production is finally slowing down a bit and I have a lot of brown slimy gunk inside all of my plumbing pipes, pumps, etc. I feed very heavy and I have about 70 fish total in both tanks.
So, this method of nitrate reduction is working for the time being, but I keep waiting for something bad to happen as this is still a new area for reef hobbyists like myself. I am not dosing anything else besides the vodka. I have NO problem algae and my fuge algae is still growing at current dosing regimen. Corals and fish all look great, even getting good growth on the softies which I thought might slow down.