Kalk with Vinegar... How much to add?

[bdare]

Hi,

I hope someone can help me out. My system is about 60 total gallons. Right now I top off with fully saturated limewater (2tsp / gallon). I evaporate about 1 gallon / day and my alk drops about .5 - 1 dkh / week (9 to 8). If I can I'd like to add vinegar to my kalk so more can be disolved rather than dosing 2 part (I'm lazy).

From Randy's article "What Your Grandmother Never Told You About Limewater" is the following:

How much can be used? The more vinegar that is used, the lower the pH of both the limewater and the aquarium will be. One reasonable point to shoot for is to add about the same amount of total CO2 via the vinegar as is needed by the lime to form HCO3-. This balance is roughly matched by using three level teaspoons of solid lime per gallon of limewater, and 45 ml of vinegar per gallon of limewater. For those aquarists choosing to use vinegar in limewater, these values are a suitable starting point. Note that the pH of the limewater is still quite high, so slow dosing is usually required.

What I'd like to know is if that equation can be halved. It seems like a lot of vinegar to add from the start and I'm worried about algae / cyano outbreaks. What would be a good starting point considering my concerns?

Also, how should I mix it? I read one article that said to try to mix the kalk in vinegar BEFORE adding it to RO/DI. Can I just add the vinegar to the RO/DI before the Kalk?

Thank in advance!
Ben

 

[Randy Holmes-Farley]

The order of mixing is unimportant, but I would not store diluted vinegar in RO/DI for an extended period as bacteria will consume it.

It is certainly fine to start with as little vinegar as you need. It may be desirable to use as little as possible to attain your goal. That said, a little vinegar won't boost the potency all that much. But in any case, starting slow is fine.

Vinegar will not drive green algae. If anything, it will drive bacteria that compete with algae for nutrients. It might drive cyano, but unless that is a problem, I would not worry about it unless and until it happens.

 

[bdare]

Thanks Randy! I knew you'd come!

So... adding like 20ml of vinegar / gallon and an extra 1/2 tsp of kalk would work?

I've never put vinegar in my tank before and 45 ml just seems like a lot. Makes me nervous....

 

[Randy Holmes-Farley]

It is worth a try, yes. Remember it is 45 mL per gallon of limewater. Also remember that vinegar is only 5% acetic acid and 95% water. So think of 45 mL as 2.2 mL of acetic acid.

 

[bdare]

<a href=showthread.php?s=&postid=12079642#post12079642 target=_blank>Originally posted</a> by Randy Holmes-Farley
Also remember that vinegar is only 5% acetic acid and 95% water. So think of 45 mL as 2.2 mL of acetic acid.

AHHHH!!! That makes me feel much better! I'll give it a shot and let you know how it works out.

Thanks again, and "Happy Reefing"

 

[Randy Holmes-Farley]

:lol:

Yes, Happy Reefing.

 

[BradR]

The way I read it this increases the dosed calcium by 25%?

 

[bertoni]

Yes, although it's possible to use up to 3 tsp per gallon, for 50% more than normal saturated limewater.

 

[sditch]

I have a 10 gal. RO\DI topoff water that runs though a Kalk reactor for my auto topoff. Can I add Vineger to the 10 gal. of freash RO\DI for the top off. It goes though it in about a week.

-Sean

 

[Randy Holmes-Farley]

No. That is one of the drawbacks to reactors. Bacteria will consume the vinegar and produce CO2 while it is sitting around diluted, which in turn will deplete the limewater, not enhance it.

 

[sditch]

Thanks Doc......I was going to try that and Im glad I gid not.

 

[Randy Holmes-Farley]

You're welcome.

Happy reefing.

 

[bdare]

Hey Randy,

My tank looks a little cloudy this morning. Should I assume that's the bacteria bloom?

Thank,
Ben

 

[Randy Holmes-Farley]

Could be, yes. The tank has never been cloudy before? Other possibilities include stirred up sand or detritus, stuff from cleaning the glass, or a spawning event.

 

[bdare]

Hey Randy,

The tank of course gets cloudy when I'm "fiddlin" with the tank, but this is different. Looking through the length of the tank it's just not crystal clear like it usually is.

I've added a total of 180ml of vinegar to my ATO container (I went ahead and did 45ml / gallon). Not all of that has been dosed into the tank yet.

I can't decide if I should add kalk with or without next time I fill the 5 gallon bucket...

Thanks again,
Ben

 

[Randy Holmes-Farley]

It certainly may be extra bacteria int the water. that isn't necessarily;y a problem, but may be unattractive. I prefer to dose without vinegar, but ordinary limewater is plenty adequate for my system.

 

[bdare]

Hey Randy,

One additional question... I also replaced my GFO and carbon on Friday. Since then I've had a problem keeping Alk up. It's been dropping about 1dkh / day.

Since the original reason I wanted to start adding more Kalk was to keep my alk from dropping I'm slightly irritated.

I've heard you say (well... read actually) that too much GFO or carbon can cause a drop in Alk. Could that be what's going on? I've got 2 phosban reactors running. The one with carbon is about 1/3 - 1/2 full of ROX. The reactor with GFO has about 2" of media (not sure how much...)

How does that work exactly (in lame man's terms ). If GFO is supposed to take up phosphate and carbon is supposed to take up DOCs... where does the consupmtion of Alk come into play?

Thanks again,
Ben

 

[DennisRB]

I found that when first adding vinegar the water gets clouded easily by bacteria, but its like the tank gets used to it, and then it isn't effected in the same way with even larger doses of vinegar.

 

[bdare]

Hey Dennis,

Thanks for the response! About how long did it take to clear up? If it's just a bacterail bloom I'm really not concearned... just unsightly as Randy noted.

Ben

 

[Randy Holmes-Farley]

Adding limewater can raise pH, and higher pH at the same alkalinity can actually increase demand for calcium and alkalinity, so that is one reason it may have dropped.

Another is reduced phosphate, which can increase calcification and also abiotic precipitation of calcium carbonate. Finally, the iron in GFO can accelerate precipitation of calcium carbonate downstream from the GFO.

Any or all of these may have contributed to a lower in alkalinity.

Did you maintain whatever you have been using to maintain alkalinity?

Finally, vinegar in limewater can reduce the alkalinity until the vinegar is actually consumed by bacteria. So there may be an effect there as well, depending on how much unconsumed acetate there is still in the water when you test it.