Another kalk+vinegar in ATO question

[bobafet1]

Ok, here's my situation.
300 gallon mixed reef tank
30 gallon ATO reservoir that is gravity fed to a Kent float valve in the sump

I currently have a kalk reactor but now that I've been doing some research I'm starting to realize that it may be pointless. I plan on doing the kalk+vinegar method inmy ATO reservoir but here's what I'm not sure about:

1. After I initially stir in the kalk and vinegar solution into the ATO does the vinegar stay suspended or does it settle to the bottom?

2. Do I need to hook up a powerhead in my ATO to keep the solution suspended? I've read that it's best to let the solution settle so it doesn't mix with Co2 and create calcium carbonate but I'm not sure if that only applies to a kalk solution without vinegar.

3. Do I start with the recommended 45ml vinegar/ 3 teaspons kalk per gallon of RO or gradually work up to it?


My biggest fear is that I'm dumping all this solution into my ATO only to have it settle to the bottom where it will be dispensed in a higher concentration to my tank. Right now I'm still using a kalk reactor in line between the ATO and sump. I just started adding vinegar to it for the first time but the problem is that I don't know when all the vinegar has been dispensed or when it needs to be replaced.

Any info is appreciated. I just hate the idea of dumping a higher concentration of stuff into my tank and causing a crash.

 

[bertoni]

The vinegar will stay suspended without stirring. Stirring will bring carbon dioxide into the water, which will combine with the Kalk to form calcium carbonate, which is very fine sand, even if there's vinegar in the mix.

I don't know how much Kalk your tank will need. I'd probably start with 2 tsp per gallon, which will dissolve without vinegar, and watch that carefully. You should be able to get a good trend line with a few days worth of measurements.

 

[bobafet1]

Thanks Bertoni!
I guess I will start with 1/2 the recommended dosage and work my way up.

 

[bertoni]

You're welcome. That sounds like a fine plan to me.

 

[bobafet1]

Ok, so I'm thinking leaving the water isn't working out like I thought. My reservoir finally used up most the water however I'm noticing almost all the kalk left sitting on the bottom. I was hoping it would disperse the kalk a little more evenly but I don't see how that could happen if it isn't stirred occasionally. I think I'm going to add a PH on timer to keep it stirred up and see how that works.

 

[ReefsandGeeks]

how much Kalk did you add to the water? anything over 2tsp/gallon will not dissolve and will just settle on the bottom. The dissolved stuff will stay in solution unless CO2 is introduced. if you read "what your grandma never told you about limewater" somewhere it says how you can check the strength of the kalk by checking the pH. If it's still reading the pH of full strength, than mixing will do nothing but put undissolved kalk into your tank (bad thing)

 

[tmz]

The slurry is likely settled precipitated impurites or excess undissoved kalk . After initially stirring in the kalk just let it settle for an hour or two and sit still ;then dose only the clearer limewater freom a point above the slurry buid up . Stirring it particulary in an unsealed reservoir is ill advised as Jon noted.

 

[bobafet1]

I think I see what my problem may have been. I remembered that I added 30 teaspoons of kalk to 300ml of vinegar to 25 gallons of water. I was trying to start off slow so I added less kalk (max would have been 50 teaspoons) and figured I'd dose vinegar based on 20 gallons of water. However, I forgot to multiply the recommended dosage of 15ml/1 qt. times 4 to arrive at the correct dosage per gallon. So, I only dosed 1/4 of the amount of vinegar that I needed to dissolve the kalk. What I'm seeing is most likely undissolved kalk or calcium carbonate. I filled the reservoir back up with about 15 gallons of water. Should I dose more vinegar and give it a stir just once? Or, waste it all and start from scratch?

 

[bertoni]

Stirring will convert the Kalk to sand, so if the bucket has been stirred a lot, the Kalk might be past recovery. Otherwise, it'll dissolve when some more fresh water is added. You could try adding the water, and see how much dissolves.

 

[bobafet1]

Stirring will convert the Kalk to sand, so if the bucket has been stirred a lot, the Kalk might be past recovery. Otherwise, it'll dissolve when some more fresh water is added. You could try adding the water, and see how much dissolves.

would the vinegar break down the calcium carbonate back to the "good stuff"?

 

[bertoni]

Yes, to some extent. It requires two moles of acetic acid per mole of calcium carbonate, or a bit more acetic acid by weight. That's a lot of vinegar. It would be the same as dosing calcium acetate if you redissolved all of of the calcium carbonate, which might be a significant organic carbon input.

 

[tmz]

It might also breakdown the bad stuff.

 

[Felixc]

I am about to incorporate Kalk and vinegar into my 15g ATO reservoir feeding a 100g soft coral tank which has an evaporation rate of about 1/2 gallon per day. I am not 100% sure on the steps to mixing so could someone please verify if this is correct:

1. fill reservoir with RO/DI water
2. add vinegar and mix with pump for 1-2 minutes
3. add Kalk and mix with pump for 1-2 minutes
4. remove pump, cover reservoir, allow kalk to settle (1 hour) and start adding to main tank, no further mixing is required??
5. once reservoir is empty, repeat step one, residual powder can be mixed in with the next batch

Will the vinegar and Kalk mix be stable for 30 days without any other intervention or mixing??

If Vodka were to be added, do I just squeeze it in between step 2 and 3?

Thanks in advance

 

[bertoni]

That's a lot more stirring than is necessary for most container sizes, and stirring once should be fine. Stirring brings carbon dioxide into the air, which converts the lime into calcium carbonate (fine sand).

The reservoir probably will have some residue at the bottom, so I'd refill it before it becomes completely dry. The vinegar-lime mixture will be fine for30 days as long as it isn't stirred. Vodka can be added, too, at any point before stirring.