Vodka dosing. po4 dropping to quick?

Defect · Nov 18, 2014

Hello,

First I will start with why I am dosing in the first place. My tank is 9 months old at this point and my growth and color of my sps have been poor to say the least...not all of them but most. I also have a acro that I received damaged in shipping and a decent amount of tips were dead/dying. These tips have grown algae on them green algae and what appears to be cyano. For these reasons I figured that I had a po4 problem.

So I have been trying vodka dosing for 8 days now. My tank is 51 gallons and have a 25 gallon sump with my actual water volume probably around 45 gallon....? So I started my dose off at .15 ml of 80 proof vodka for 3 days then upped it to .30 for the next 3 days and have now upped it to .4 ml a day.

My po4 started off at .05 according to my hanna low range checker. The first 3 days my po4 stayed the same at .05, day 4 I tested and it read .07 and at day 7 it went to 0.00. Tested twice to see if maybe I got it wrong but tested twice at 0. Today I tested again and got a reading of 0. From what I have read on vodka dosing this does not seem possible....

My nitrates were also a little higher then wanted sitting at 5 when I first started dosing. Now they seem to have dropped to 2.

Is this possible or am I just testing wrong here? The acro still has the cyano/gha/green algae on it but I have no idea how long it will take for it to leave the acro in question with little phosphates in the water.

Thanks,

Aaron

Reefing Madness · Nov 18, 2014

Doesnt sound right for either test. Your not dosing enough to get either one to budge, especially phosphate number. With yiur phosphate being that low, you kight want to throw in some gfo, or if you dont want the reactor go with a liquid Lanthanum product that you dose when you need.
What are you running in the sump? Anything that wpukd have sprung to life and ate up some phosphate?

Randy Holmes-Farley · Nov 18, 2014

I'd be surprised if the phosphate really dropped that much in that time, but I suppose it is possible.

I'd keep at the same dose for a bit and see what happens.

Defect · Nov 18, 2014

I have some GAC that I put in about a month ago. I also skim fairly wet and have chaeto in my sump but that and the skimmer have been there the entire time. Maybe the 4 tablespoons of GAC are doing something. Just running it passively in my sump with a pump pushing water around in the area where the GAC is and also where the dosing pump drops alk and cal.