Vodka dosing

[me2003]

This may remove some organics or phosphates. The risks seem to be
1. Acros may turn brown. The zooxanthaellae may also use the vodka
to grow and not use resources for photosynthesis.

2. I have read and experienced issues with soft corals. I would watch for
the infection that starts on the tips of green tree corals.

3. If you stop dosing your tank will have to readjust.

If you are dedicated enough to do vodka dosing, you would probably
have a good reef system anyway. This issue and the variation from tank to
tank would make scientific testing difficult.
This is not to discourage testing. I am not sure how you could validate
any hypothesis on vodka dosings effects.

 

[Greg Hiller]

>What is the bottom line goal of this? Make corals grow prettier and brighter, right? How does growing more bacteria and skimming more nutrients out do that? Just clearer water and more light I'm guessing, but don't they need at least some of the nutrients you would skim out if this method works? (not that we need to start an overskimming debate too)<

Cindy, the standard dogma is that corals (most) can grow very well even in very nutrient poor waters. Many believe that an Indo-Pacific reef is quite low in dissolved nutrients, but might be higher in particulate nutrients (plankton) than our tanks are. Many hobbyists are always looking for ways to drive the dissolved nutrients down to a low level to improve water clarity. Some believe that many corals (like SPS) are 'unhappy' with high nutrient levels. There is some research (I believe) that suggests that high levels of phosphate in the water column can chemically 'poison' the sites of calcium carbonate deposition that are occuring within the coral tissue.

Remember, driving nutrient levels down is always more difficult that drving them up. I can dump in a bottle of flake food in 2 seconds if I want nutrients up. I think Jeremy told me once that that was the best way to get lots of critters to grow for mandarins to eat..... No....I said that.

 

[~Flighty~]

Admittedly I don't do much reading about SPS, but aren't some of the issues with spindly growth and susceptibility to RTN being correlated with nutrient poor water? That's why you hear of reefers upping their fish loads in SPS tanks in other countries. Again, I'm just asking and don't have much knowledge on the SPS stuff.

 

[Liam]

Admittedly I don't do much reading about SPS, but aren't some of the issues with spindly growth and susceptibility to RTN being correlated with nutrient poor water? That's why you hear of reefers upping their fish loads in SPS tanks in other countries. Again, I'm just asking and don't have much knowledge on the SPS stuff.

i think it is similar to the sandbed arguments Cindy,there are two sides to the nutrient argument

 

[RichConley]

Admittedly I don't do much reading about SPS, but aren't some of the issues with spindly growth and susceptibility to RTN being correlated with nutrient poor water? That's why you hear of reefers upping their fish loads in SPS tanks in other countries. Again, I'm just asking and don't have much knowledge on the SPS stuff.

Cindy, my understanding is something like this:

SPS Coral polyps feed; they need food, IE suspended particulate matter: bacteria,food,oyster eggs, baby clown fish, whatever.

SPS dont like high phosphate.

So the idea is to add a lot of food (via fish/food/whatever) and then get it out if the corals dont eat it.


unfortunately, theres not a ton of research on how/what these corals actually eat, so its tough to tell how much of this stuff is valid.

 

[Liam]

maybe its time for a group buy on Grey Goose

 

[Matt L.]

I feel drunk...

...after reading all of this I can't tell if its a circular argument, or if the room is spinning...

Anyhow, if anyone can think of a study, then I'll try and do it this Spring.

The first study I can think of is to test whether our tank water is low on carbin (carbon limitted). That's easy to do with a TOC (Total Organic Carbon) test.

Matt

 

[NateHanson]

How do you measure if the bacteria in your tank are carbon limited, if you don't have a way to measure the growth of bacteria in your tank? You'd have to add carbon and see if the bacterial population increases.

Actually, you could probably use your new spec for this. Measure the A280 of a water sample daily without dosing carbon, to get an average bacterial population in the water column. Dose carbon somehow, and measure A280 for a while on more water samples. See if there's more DNA in the water.

Problem I forsee is that there won't be enough DNA in the water sample to get any real reading. If you steal a microfuge from the lab you could do this experiment by spinning down your samples and resuspending them in a small volume of ddH20 - of course then you'd need to steal a Pipetman too, and some microcuvettes. Maybe you'd better just do this experiment at work.

 

[lactrain]

Grey Goose? Cheesus! that be the the line for me .... I love my reef but dang tootin I share that with anyone.

Bet you all have the sponsors shaking in their boots right now ... thinking that their all gonna have to go out and apply for liqour licences to stock the next fad supplement and card everyone as they walk in the door.

Wonder what the benefits "Tang" would have on the reef tank doesnt it sound a bit more user friendly, its got vitamin C!

I must give youll credit for this thread, and I must admit I am impressed with the theory you all are documenting, but im having a hard time entertaining the thought of how im gonna make sense to the wife how need to stop a package store so i can feed my reef tank.

Len

 

[Matt L.]

How do you measure if the bacteria in your tank are carbon limited, if you don't have a way to measure the growth of bacteria in your tank? You'd have to add carbon and see if the bacterial population increases.

Actually, you could probably use your new spec for this. Measure the A280 of a water sample daily without dosing carbon, to get an average bacterial population in the water column. Dose carbon somehow, and measure A280 for a while on more water samples. See if there's more DNA in the water.

Problem I forsee is that there won't be enough DNA in the water sample to get any real reading. If you steal a microfuge from the lab you could do this experiment by spinning down your samples and resuspending them in a small volume of ddH20 - of course then you'd need to steal a Pipetman too, and some microcuvettes. Maybe you'd better just do this experiment at work.

Nate,

My experimental proposal is slightly different. I say, look at the tank water first, and see if carbon really is limitting.

If there is no carbon present in the water column (that is not already part of cells), then it is plausible that carbon is limitting.

Cells are easy enough to remove from the water.

If there is a lrage* quantity of organic carbon present in the water, then carbon cannot be limitting.

To test the quantity of carbon in the water, I would use TOC (which is a hard test to do, but something I could sneak in on a weekend and conduct).

That's my proposal.

Then, if we find out that carbon is not present in the water column, we can do your test to see if microorganisms in the water column respond to the addition of carbon.

Matt

* large compared to the amount of carbon from ethanol. If ethanol would be just a drop in the bucket, then the theory of using ethanol to increase carbon would be wrong.

 

[NateHanson]

Ok, but I still don't think that tests whether carbon is the limiting nutrient for bacterial growth in our tanks. Your experiment can reject the hypothesis, but can't prove it. A positive result of your experiment would just suggest that there isn't a "large" (which seems a bit subjective) ammount of carbon in the water. But says nothing of whether it's limiting. No matter how low the carbon levels are, Carbon-dosing won't increase bacterial populations if . . . cysteine (insert whatever molecular building block you like here) is the ultimately limiting nutrient.

Why not test the factor you're wondering about - bacterial growth? If you want to know whether Carbon's the limiting nutrient you have to see bacterial growth in response to carbon dosing.

 

[Greg Hiller]

>Why not test the factor you're wondering about - bacterial growth?<

Exactly....and in my first post I mentioned that in a sense I'd already done this.

> I actually came close to this once when I dumped a few teaspoons of table sugar into a tank accidentily. It was early in my reef tank days and I didn't have much. As I recall the water got cloudy, then cleared, no losses, but I'm sure you could wipe out a tank if you added too much at once. <

If the bacteria were not limited by the availablilty of the carbon, why did they grow?

A simple and fairly scientific test (outside of a tank, with controls) would be to take some tank water out, split into two containers (or more if you want replicates). Add a known amount of ethanol. Place at 80F and shake the flasks for a day or so. Do a bacterial count. No problem. And, I'd be willing to bet that you will see significant bacterial growth. You could even, if you had a good assay, check for PO4 in the water before and after you spin the bacteria that grow out.

 

[shawn]

Well, I guess I'll relate my own vodka dosing experience...

I have had higher nitrate and phosphate levels then I'd prefer. I thought the vodka dosing information I had read on RC looked interesting, and decided to give it a try. I took measurements of my nitrates and phosphates, and carefully controlled my vodka doses. I increased the dose levels much more slowly, and capped the doses sooner, than related in the RC article.

Bottom line, my nitrate measurements went to levels lower than I'd ever before measured. I also had a lowering of phosphates, but they were not as significant (but were probably statistically significant). I once noticed a slight haze in in the water like I hadn't experienced before, and that bothered me. Also, I thought I noticed a slight browning of my (few) sps. So other than the lower measurements, I didn't literally "see" any other benefits. That combined with the daily bother of dosing and the general bad press on vodka dosing, lead me to decide to discontinue the practice.

So, though I feel confident that my measurements showed "benefits" of vodka dosing, my lack of subjective benefits lead me to stop the practice. However, if there were a good automatic dosing method and greater numbers of others reporting good results, I might be inclined to try the experiment again.

 

[Greg Hiller]

Shawn, very interesting...thanks for posting.

May I ask...did you have a strong skimmer?

 

[Liam]

out of interest i did try running some PO4 tests on some skimmate.I diluted it stages down to a ratio of 20:1 to eliminate color and hopefully bring the sample into the range of the kit.I did get a slight color change in the test at a ratio of 10:1 but the sample still had color at this point and no comparison was possible.I repeated the test at 10;1 and no change was noticable on the second test.I am only using a salifert kit so my means are limited but all the same i could not measure any phosphate in the skimmate.
I also tested my NO3(in tank) and could not detect any within the 5 min time on the test,however after 15 mins a very slight color was noticed in my test.I am presuming this color change is due to a smaller amount of No3 being present but am not sure if this could be normal once you go over the alloted time for the test(Greg/Matt?).
Hmmmmm were's the vodka

 

[shawn]

Shawn, very interesting...thanks for posting.

May I ask...did you have a strong skimmer?

I'd guess by most reefer's standards, no. I have a Remora Pro with a Mag 3, and usually run with the collection cup at the lowest position (wet). The display is a 75g, with a 90g gross capacity sump/refugium.

 

[starrfish]

If you already have 0 or very low phosphates and nitrates (which I'm assuming you do if you are running a refugium), why would you even bother trying this? When I was running my 75 with no refugium, I would do anything to get the phosphates and nitrates down. Now that I have a refugium on my new tank, all of my readings are negligible. I would be afraid to upset a good thing - if it ain't broke don't fix it.

 

[Greg Hiller]

>- if it ain't broke don't fix it<

Agreed, but it would always be nice to be able to add that 'one more fish', or feed the fish and inverts that you have more. An inexpensive method of nutrient removal (assuming of course that it works) is always a temptation for reefers to 'tinker'.

 

[me2003]

I think both experiments have value. If there is a large level of carbon available in the tank, I would think there may be other limiting factors.
I would also be interested in the change in the count of bacteria over time.
After time does return to the same level as when the experiment started or
maintain a higher bacteria level.
I also like to see a third experiment on how the dosing changes the colors/growth of acros. This would be more complex to setup.
Here are the questions I have on vodka dosing.

Is vodka preferred by certain bacteria?
Is the export on nutrients/Nitrogen and phosphorus compounds
increased by the export of these bacteria?
Is this effect long term? Are you creating a bacterial bloom and removing it
with protein skimming each bloom or are you creating a long term higher
level of bacteria?
Does zooxanthaellae also use vodka to grow? Does this change the color of your corals?
How does your tank food chain react to the increased level of bacteria?

This is my hypothesis with little evidence to prove it.
Bacteria are not carbon limited. The addition of vodka/sugar is easily absorbed by bacteria giving them a temporary competitive advantage. This causes a bloom in the tank that is partially removed by protein skimming. This removes the high nutrient levels.
The tank reacts with an increase in bacteria consumers which brings the bacteria levels back to normal. You add vodka and start the cycle again. Zooxanthaellae also increases by absorption changing the color of your acros.

 

[shawn]

If you already have 0 or very low phosphates and nitrates (which I'm assuming you do if you are running a refugium), why would you even bother trying this?

Well, in my case that is a bad assumption.

I looked back at my notes (which are only slightly better than my memory), and here is what I can decipher. (Note that my previous statement that the effect on the P04 was less was incorrect).

Day 1: NO3 = 25ppm, PO4 = .25ppm, dose 0.5mL/day
Day 5: NO3 = 25ppm, PO4 = .25ppm, dose 1.0mL/day
Day 10: NO3 = 25ppm, PO4 = .25ppm, dose 1.5mL/day
Day 15: NO3 = 17ppm, PO4 = .25ppm, dose 2.0mL/day
Day 20: dose 2.5mL/day
Day 27: NO3 = 17ppm, PO4 = .20ppm, dose 2.5mL/day
Day 31: NO3 = 7ppm, PO4 = .05ppm, dose 2.5mL/day Water clouded
Day 32: NO3 = 5ppm, PO4 = .03ppm, dose 2.5mL/day Skimmer filled in ~8 hours

This is a 75g with 90g sump (maybe ~130g of water?). I believe I stopped dosing at that point. The values measured at the start of the dosing had been fairly close to those levels for the previous year.

Since then (about a year ago) the NO3 has dropped to 0ppm, and the PO4 has increased to .12ppm (it did so fairly quickly after I stopped dosing). I have reduced feeding somewhat, which probably accounts for the long term reduction from the values measured before starting dosing.