The reason I'm updating the Vinegar and Vodka dosing charts is two-fold:
1. The ramp was unnecessarily slow. There was no perceived benefit to such a tedious ramp, and it led to reefers quitting because they thought carbon dosing didn't work.
2. The ramp did not scale up correctly at all. A 40x larger tank only received 2x the needed dose. (A 1,000-gallon tank only received twice the dose of a 25-gallon tank).
Why should I carbon dose?
We will refer to carbon dosing as adding any readily metabolized organic. Carbon dosing is NOT equal to dosing carbohydrates.
Reef tanks are notoriously carbon-limited. We have an excess of P and N, and the bacteria in our tank lack the carbon to continue consuming nitrogen and phosphorous.
Carbon dosing is a fantastic way to lower nutrients, more specifically nitrate. The reason is three-fold:
1. Organisms such as bacteria & plankton contain much more nitrogen than phosphorous. The red field ratio is 16:1, meaning there are 16 parts nitrogen to 1 part phosphorous.
2. Denitrification is a process that happens in anaerobic conditions (little to no oxygen). These bacteria require an organic to oxidize the nitrate molecule (NO3-) into Nitrogen (N2). They breathe the oxygen that is attached to the nitrate molecule. Thus, there will be NO phosphate consumed in this process.
Here is the equation by
@Randy Holmes-Farley :
organic + 124 NO3– + 124 H+ → 122 CO2 + 70 N2 + 208 H2O
3.We have an immense reservoir of phosphate bound to calcium carbonate rocks and sand. To put to pespective, a 50% water change with nutrient-free water will successfully reduce your nutrient values by 1/2. More often than not, the phosphate value will climb right back up near the starting point after a day; PO4 tries to be in constant equilibrium with the bulk water column and calcium carbonate surfaces.
For these reasons, I do NOT recommend dosing carbon solely for controlling phosphates. It is likey to deplete nitrate before seeing phopshates significantly reduce.
What are the benefits of carbon dosing?
Besides reducing nitrate, spurring bacteria is the main benefit. This bacteria can feed many organisms and filter feeds (such as desirable sponges) in a tank. Coals and sponges can directly metabolize acetate. Acetate is one of the highest turnover organic in the ocean. Thus, opting for vinegar can be very natural.
What about other carbon sources such as NP Bacto Balance, NOPOX, or Sugar?
You can carbon dose with NP Bacto Balance or NOPOX, but dosing straight vinegar or vodka is cheaper and readily available in stores.
One caveat is dosing sugar. While it was popular to dose sugar to a tank several decades ago, it has largely fallen out of favor. It tends to "brown out" certain corals. I wouldn't consider dosing sugar.
Vodka is eight times more concentrated, so the vodka chart has the same ramp as the vinegar chart.
What kind of vinegar or vodka should I use?
Plain Distilled vinegar (5% acidity) from the grocery store is best. NOT filtered vinegar.
Unflavored 80 proof vodka (40% ethanol) is adequete.
Instructions and rules to follow when carbon dosing with my charts:
1. Only dose during daylight hours. Carbon dosing will reduce pH and oxygen, so it's wise to dose while those parameters are naturally at their highest.
2. Skimming and good surface agitation is encouraged. If you don't have a skimmer, stay on the lower end of the chart, and don't progress unless it's clear the tank is fine.
3. You can dose vodka in one shot (bolus dosing), but vinegar is best spread-out with a dosing pump throughout the daylight hours.
4. Vinegar and Vodka have the same pH-lowering effect, but vinegar is more upfront, while vodka is all later as it becomes consumed by bacteria. You cannot easily detect the pH drop from vodka, but they are equal when comparing the chart dosages for tank size.
5. You do not need to increase the dose after week 2 if nitrates are reducing earlier.
6. Watch your tank and make observations. Once your nutrients are in line, find a small maintenance dose for your tank. You choose the final dose based on your testing and tank inhabitants.
7. Keep track of nutrients and ensure they don't bottom out. Nitrates won't bottom overnight; you won't wake up on the second day and see 100 ppm turn to 0.00 ppm. It's much more gradual than that.
8. More people notice cyano issues with vodka than with vinegar. If that is the case, switching to vinegar is a wise choice.
Here are the charts. If you have any questions, feel free to ask.
