Vodka/vinegar (6:1) shelf life?

[CaptainDave]

I searched and couldn't find the answer to this; if it has been addressed already, I apologize.

I know that diluted vinegar has a short shelf life as the acidity is reduced and bacteria can then utilize the carbon.

I'm just beginning carbon dosing, and after reading I've decided I'll be using a 6 to 1 mixture of vodka and vinegar (it seems this is similar to what's in NOPOX based on some threads I read, and I like the idea of bacterial diversity). My question is this: will a 6:1 mixture of vodka and vinegar have a relatively long shelf life; e.g., long enough to mix up a gallon or so and dose it to a 30g tank?

Apparently the pH of vodka is about 4 (compared to vinegar at about 2.6, according to google), so my hypothesis is that mixing with vodka wouldn't raise the pH enough to allow bacteria to grow in the storage vessel.

Thanks for your reply!

[biecacka]

So I dose vodka /vinegar and I dose about 6ml of vodka and 20ml of vinegar. I had it up to 9/30. So about 1 pay vodka and 10 part vinegar
I am not sure about premixing it though. I think in the chemistry forum I read it is not a suggested method but let me go back and look..
Corey

[CaptainDave]

So I dose vodka /vinegar and I dose about 6ml of vodka and 20ml of vinegar. I had it up to 9/30. So about 1 pay vodka and 10 part vinegar
I am not sure about premixing it though. I think in the chemistry forum I read it is not a suggested method but let me go back and look..
Corey



Hmm, did I have the ratio backwards? Should it be 6 parts vinegar to 1 part vodka?

[biecacka]

I had always seen less vodka (that's the ONLY time LESS vodka is acceptable[emoji38])
I got the ratio from the chemistry forum and it works great for me.

Corey

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[disc1]

Apparently the pH of vodka is about 4 (compared to vinegar at about 2.6, according to google), so my hypothesis is that mixing with vodka wouldn't raise the pH enough to allow bacteria to grow in the storage vessel.


That's not a safe assumption. Vodka should have very near a neutral pH. You'll measure more or less because vodka has absolutely no buffering capacity, so a little bit of CO2 drops the pH quite a bit. But you can't make any assumptions about what the pH of the mixture will be. pH doesn't work like that.

[Walla2GSP]

I'm far from an expert on the subject, but i mixed some VSV for carbon dosing. My ratio was way different than what you guys are recommending, but I premixed and refrigerated because I needed .25mL at a time. After one week there was a green color to the mixture. Just sharing my experience, not recommending that you premix.

[CaptainDave]

Thanks for the replies, everyone. I mixed up some 6:1 vodka:vinegar and put it in my dosing reservoir, I will keep a close eye on it and report back if it starts to go bad.

[Piper27]

I use a mix at half and half, no problems. It's clean everytime I check it and refill each month. I was told to mix it by a friend who had an amazing reef tank and is very smart so I didn't think there would be an issue. There hasn't been for me, I have never heard of mixing vodka and vinegar causing an issue.
I dose 50ml of vodka and 50ml of vinegar daily on my almost 400 gallon system.

[CaptainDave]

I use a mix at half and half, no problems. It's clean everytime I check it and refill each month. I was told to mix it by a friend who had an amazing reef tank and is very smart so I didn't think there would be an issue. There hasn't been for me, I have never heard of mixing vodka and vinegar causing an issue.

I dose 50ml of vodka and 50ml of vinegar daily on my almost 400 gallon system.



That's good to know that 50/50 is stable over a month at least, thanks.

[Rakie]

Hmm, did I have the ratio backwards? Should it be 6 parts vinegar to 1 part vodka?

I believe you had the ratio backwards. Vodka is extremely potent for carbon dosing, Vinegar is quite mild.

[CaptainDave]

I believe you had the ratio backwards. Vodka is extremely potent for carbon dosing, Vinegar is quite mild.



Thanks, after reading some more I think you're right. However, I think vodka is preferable for me because I don't want the pH drop with vinegar. I am still interested in maybe trying to create some bacteria diversity by using a mixture, so I'm going to go with mostly vodka for now. I may increase the ratio later on as described above (I know I will have to increase the total amount dosed if I increase the vinegar portion)

[disc1]

The vinegar shouldn't cause a noticeable pH drop. If it does your Alk may be low.

[hkgar]

I dose a mixture of 70% vinegar and 30% vodka. Using Apex I dose hourly from 10 AM to 8 PM (period that the lights are on. This will minimize any effect on ph. My ph will reach 8.2 during the day and 7.9 after lights out.
https://www.reeftronics.net/graphns.php?probe=02&period=week&member=garyk

[CaptainDave]

Well, so far my 6:1 mix still looks just fine, no sign of bacterial growth

[hkgar]

The alcohol would probably kill any bacteria growth.

[waterjockey]

I run a mix of 33% vinegar, 33% vodka, 33% ro/do water. It has been sitting in the dosing container for about 3 months so far with no issues. I made up a gallon, at my present dosing rate of 2ml/day, that should last about 5 years...hope it doesn't go bad lol (I used to dose a lot more)

[reefgeezer]

If the goal is to get about the same amount of carbon input from both the vinegar and vodka, I think maybe 9 parts Vinegar to 1 part Vodka would be about right. Realistically, any ratio will work as long as you don't change it.

As far as shelf life is concerned, I don't believe there is an issue with storage as long as the mixture is not so dilute that bacteria can survive in it.