Sugar dosing experiment

Administrator

I was disappointed to find that my nitrates were at around 20 ppm according to the API test kit when I checked them yesterday morning. I'd hoped nitrates would no longer be an issue between adding a lot of rock to my tank over the summer and feeding light every other day or so. They had stayed at around 5 or 10 ppm for a while. I removed all of the rock from my sump not long ago (I still have plenty in the tank) because it appeared to be accumulating detritus, so I wonder if that is the reason my nitrates are now higher than they were.

Anyhow, the nearby store sells distilled Poland Spring for $1.95 a gallon, so doing any kind of significant water change that would bring the nitrates down appreciably would not be cheap. I searched around for something I could use to lower nitrates without having to perform a large water change, and came across carbon dosing.

The idea, as I understand it, is that adding specific amounts of either sugar or vodka to the aquarium water causes bacteria that consumes it to propagate. This bacteria allegedly also converts nitrates into nitrogen gas, and may have some impact on phosphates as well.

I don't plan to dose long term as a substitute for good husbandry, but at the moment I would rather not have to deal with a several hour long, messy, relatively costly (as far as water changes go) water change.

I added 1/8th tsp (teaspoon) of sugar to my 55 gallon aquarium last night and will do the same tonight. On Wednesday night I'll probably add 1/4th tsp. I'll do the same Thursday, and test the water and report my findings on Friday morning.

I hope I'm not making a mistake in trying this, but I've put so much into my tank now that I owe it to my family (and myself, really) to at least see if this effortless, practically free method works the way it's been reported to by others.

catdawg426

Hope it works!

redchigh

Think that would work with freshwater?

ginagv

+1 for wanting to know if it would work for freshwater also

Gina

LisaC144

Hmmm, I'd be scared to try vodka in freshwater. I know what happens to me when I get too much vodka in me

Administrator

Hi guys,

Based on what I've read, I would not try this in a freshwater tank. From what I understand, the bacteria that grows as a result of adding the carbon consumes a lot of the oxygen in the water, so it is highly recommended that you try this only if you have a protein skimmer which both removes the bacteria after it's consumed nitrates and phosphates, and replenishes the oxygen in the water.

As for my results so far, I dosed the following:

Monday night: 1/8 tsp
Tuesday night: 1/8 tsp
Wednesday night: 1/4 tsp
Thursday morning: 1/2 tsp
Friday morning: 1/2 tsp

I'll test and report my nitrates when I get home from work. I've read that it's taken some people 2 weeks or so to see a difference, so it may be a bit premature but we'll see.

redchigh

Wow, it's sounding better and better...

Consumes oxygen means converts it to CO2, correct?
Sounds like a CHEAP way to supplement CO2...

Administrator

I read that the bacteria that results from adding the sugar reduces the amount of oxygen available in the water, which is why it was strongly recommended that a protein skimmer be used to replenish it. I don't know whether the oxygen the bacteria consumes is converted to CO2.

I do know that after dosing with sugar for exactly 1 week now, I am a believer. My nitrates have come down from what looked like 20+ last Monday to 5 or 10 (I can't tell the difference between these two with the API test kit) as of this morning. It looks like my phosphates are lower, too.

When I tested my nitrates last Friday, it looked like the test kit results may have been a slightly lighter shade of orange, but they still looked to be around 20. I remembered reading that some people only saw results after their tank had gotten cloudy, and their tank had only gotten cloudy after increasing the amount of sugar they dosed with. On Friday evening I added another 1/2 tsp of sugar. That got the tank cloudy. There was a definite change in the shade of orange when I tested the water Saturday morning. On Saturday I decided to "go for broke" and dosed 2 tsp. The water got cloudy later that day, my skimmer kicked into high gear, and when the water cleared up hours later my nitrates were lower still. My fish, hermit crabs, emerald crabs, peppermint shrimp, and xenia all seemed fine. I dosed 2 tsp again Sunday and Monday. I am going to do the same this morning.

On Wednesday or Thursday I will probably scale it back to dosing 1 tsp until Sunday, and then 1/2 tsp from then on assuming the nitrates don't increase.

Thinking about all of the messy, several hour long, large water changes I've done to bring my nitrates down in the past, and the expensive "nitrate reducing media" I've purchased that had no noticeable effect whatsoever, the fact that simply adding sugar to the tank significantly reduces nitrates (at least has so far) strikes me as nothing short of incredible.

Assuming the cumulative impact of sugar dosing doesn't have negative consequences, and there doesn't seem to be any reason to think it would based on everything I've read, this seems like it would save a lot of time, work, money, and frustration.

Of course, from what I understand, adding new aquarium salt replenishes many helpful trace minerals, so in addition to dosing to replenish Ca, Mag, etc., I am still going to do regular water changes. They just won't have to be nearly as large or as frequent to keep my nitrates at bay.

reefsahoy

you might want to consider adding brightwells MB7 so you get a variety of bacteria and not have a monoculture of bacteria.

Administrator

Thanks, reefs, I'll look into it. Would that be in addition to dosing with sugar, or as an alternative to it?

Have you dosed with sugar yourself or do you know people who have? If so, how did it work out?