Carbon Dosing

There is a big difference between carbon dosing and using activated carbon in our tanks. This article will explain what carbon dosing is as well as why we should consider it. Another article will cover what activated carbon is used for but I wanted to clarify they are not the same thing.

What is it?

Carbon is one of the basic building blocks of life. Everything living uses carbon in some form or another. Bacteria in our reef tanks are no exception to this. We are going to focus on the bacteria that consume nitrates and phosphates but are often limited in growth by the amount of available carbon in the tank. That’s where carbon dosing comes in.

Carbon on the periodic table

Why dose it?

As mentioned above, there are certain bacteria that actually consume our nitrates and some phosphates in our reef tanks. We like this bacteria because it helps keep our levels to safe ranges for our corals and fish. The limiting factor for this bacteria is the amount of carbon available in the tank. Once they use the carbon up, we have to add more if we want to continue seeing these bacteria numbers rise. It takes quite a bit of bacteria to reduce the nitrates in our tank. Without dosing we often see increases in nitrates because the bacteria available just can’t ever keep up.

How to dose

There are several ways to dose carbon. We will discuss using liquids like vodka, vinegar, premade products like NOPOX and some longer term products like biopellets. No matter what product you chose, start with small dosing and slowly increase the dosage up. Otherwise you will end up with a large bacterial bloom which in turn will deplete your oxygen and risk all your livestock.

Vodka – The original method of dosing carbon was using pure vodka in small amounts. The carbon is high in vodka so it was pretty easy to overdose in the beginning. See the below chart on how much to dose with vodka.

Vodka dosing

Vinegar – after some people had troubles with vodka or issues obtaining vodka to dose, they turned to another carbon source of vinegar. It takes a much larger dose of vinegar compared to vodka but it remains easier to obtain for many people as well as being cheap. Being naturally acidic some advocate for only dosing vinegar during the daytime to reduce any chances of a PH swing. Personally I don’t think it matters as you’ll likely be dosing only a few ml of vinegar a day; not enough to upset the PH of most tanks. See the below chart for dosing with vinegar.

Vinegar dosing

NOPOX – This is one of the first products to be made commercially. The product is actually called NO3:PO4-X but NOPOX for short. As I understand it, it contains a few different carbon sources including vodka and vinegar both. It has it’s own set of directions to dose with. Like anything, cut that dose in 1/2 or even 1/4 to begin and work your way up from there.

Biopellets – the lazy man’s way of dosing. This is because you add biopellets to a reactor and let it be for months on end. No need to daily dose with this product. The biggest downside is that it’s hard to control the dose you are getting. By just adding pellets and letting it sit it’s possible to overdose easily as well as making it difficult to fine tune the amount you should have. In my own tank I use biopellets to maintain my nutrients at a lower level but it does not remove them entirely from my system. I plan on utilizing NOPOX in conjunction with biopellets to really run a low nutrient system.

What’s your favorite way to carbon dose? Share in the comments what you like best and why!


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