When I started with just vodka, my phosphates were about 0.2 ppm and Nitrate was undetectable. This was around 2 months ago. Dosing just vodka, I was able to get my phosphates down to 0.12 ppm but at that point they started to creep back up again.
The NeoNitro debacle raised my phosphates to almost 0.4 ppm. After which, I kept dosing vodka and ordered some food grade NaNo3.
When I received my NaNo3, I mixed 50 grams with 2/3 gallon of distilled water for a potency of about 14484 ppm. Adding 1ml of this stuff should raise the nitrates in a 75 gallon tank by 0.05 ppm.
I started dosing this nitrate solution 3 weeks ago at 5ml/day. I gradually bumped it up to 15ml/day and 2 weeks in I finally noticed a little pink on my Salifert test, at which point I backed off to just 10ml/day.
As of today I am dosing 1.6 ml/day vodka and 10/ml day of nitrate solution. My nitrates are somewhere between 0.5 - 1 ppm, and my phosphates are lower than they've ever been at 0.025 ppm.
It's a 75 gallon tank with a small skimmer sump, so I assume with rock and sand my total volume is still around 75. I run a Reef Dynamics INS-180 skimmer and do 5 gallon weekly water changes with Instant Ocean or Reef Crystals.
I'm glad to hear things are working well for you with the sodium nitrate. I've recently switched from potassium nitrate over to sodium nitrate after I noticed potassium levels creeping up slightly each week. Both forms of nitrate are cheap so no big deal to switch over.
My own PO4 levels tested out at 0.01 today and nitrate is at 5 so I'm happy and SPS are happy as well. No GFO in use at this point either and that's with 4 automated fish flake feedings a day and one manual feeding of Mysis so there is plenty of food to go around.
Passing on a few observations for anyone else who may benefit:
When dosing nitrate the test readings follow behind the dosing regimen by a few days. Don't expect to be able to take a test reading 3 hours after dosing nitrate and expect that it will be accurate. Give it a day or two to see the full impact (the readiing will have gone up by then).
I've let my nitrate levels drop to 0 a couple times over the past few months when traveling. The wife and kids keep the feedings up though and again, no GFO. In both cases when this happened (I was away on business), PO4 levels went up to around 0.12-0.17 by the time I returned. I have a doser now, which helps.
If you find that your battle with PO4 starts to wane a bit in the months ahead in spite of adding nitrate, be sure to read up on iron and it's impact on bacteria growth. Look up Glennf's DSR method here on RC (
http://reefcentral.com/forums/showthread.php?t=2301583). From Glennf I learned that he supplements iron along with nitrate and vinegar to reduce PO4 even further. His recipe works so well that he says he sometimes has to dose a small amount of PO4 to keep his PO4 levels at ideal (around 0.03). As the story goes, vodka (carbon) and nitrate feed the bacteria (they absorb it) and those same bacteria also absorb PO4 and a little iron at the same time. Eventually iron can become a limiting factor. You need to keep up your water changes or may need to increase them. Or supplement iron via feeding, dosing or what have you. Of course, you will need to test iron to do that safely but it is worth it. When iron is in check, I saw PO4 drop again quickly and skimmer activity increased as well.
Reference:
bacteria consume iron to survive
http://dnr.wi.gov/topic/DrinkingWater/documents/pubs/ironinwell.pdf
There are plenty of other studies citing how bacteria consume iron and the one above is just the result of a quick bing search. Read up on this as it is a component to understanding the biology behind this PO4 challenge.
Happy Reefing all! :wavehand: