Vodka dosing without an accurate PO4 reading?

[broke1]

My API and Salifert test kits both show undetectable levels in their results.

My Nitrates are right around 20 and just won't seem to go down with water changes. My question would be is a Nitrate reading enough to gauge the dose of Vodka?

I am having an outbreak of Bubble algae so I know there is a Phosphate problem but it just won't show on a test.

It's around a 350 gallon system, running a large phosphate reactor with a 75 gallon fuge, so they might be hiding the phosphates from the tests. I just purchased an Orca 200 skimmer which I had hoped would help, but even though it is pulling out alot of gunk the algae still seems to be growing.

[bertoni]

Some people have been successful using vodka to reduce nitrate. I'd likely try other approaches, but vodka can work.

[tmz]

Regarding the the amount of dose, if you do decide to use vodka, a little goes a long way. Dosing too much can cause a bacterial bloom. I used vodka for about 4 months at 4ml per day for a 500g system without any discernable ill effect and a reduction in nuisance algae. I stopped because I didn't like not knowing what bacteria were growing and wether they were benign, helpful or harmful beyond the nutrient export function.

[gkyle]

I use sugar instead of vodka, and dose my 220g system with 1 tsp. per day. I had phosphate and nitrate showing zero on my Elos kits before, but a terrible algae outbreak anyway. After three weeks my algae is totally gone and my LPS and SPS have never looked better. I tried many things to get rid of the algae, including adding 170 snails, so I'm not sure which one did the trick. I have a very light dusting of diatom on my glass now that takes about a week to become noticeable, but that was a daily chore before. I was dosing 2 tsp. a day without any ill effect, but it seems that 1 tsp. is enough.