Tunze salt calculation per gallon

[varyhare]

Tonight is the first time I make my own saltwater and my Tunze salt mix bucket has no calculations. How much salt mix do I use per gallon?

I am in the process of making the RO/DI water right now so your quick responses will be greatly appreciated.

Daniel

 

[rvitko]

Ideally you mix it all at once, this is the only way you will be guaranteed the proper ratio of salts. If you cannot mix it all at once, mix it very, very thoroughly when it is dry, dump the salt back and forth between two buckets a dozen times or so. This is critical as the salts settle so all the magnesium and calcium are at the top and all the KH is at the bottom. 1 cup mixes about 2.5 gallons at 1.020, let it dissolve thoroughly and measure.

 

[varyhare]

Thanks Roger. I was able to calculate 8 cups for the 15 gal I make

 

[mcarroll]

Semi-related question: Is it appropriate to measure salt by weight, or only by volume? Wondering if humidity could make enough difference to matter if (e.g.) the salt were to be left open for a while before or in between uses? Anything else?

Thanks!

-Matt

 

[rvitko]

I don't know, but logically wight and volume would be affected by moisture so I think this would probably through off the result either way. It probably is a fairly negligible amount however.

 

[mcarroll]

I suspected....when the salt consistency noticeably changed between opening the container and the 2nd or 3rd bucket mixed (1 hour, tops) with it, I got suspicious.

Too bad as measuring by weight seems easier (for me at least).

 

[Cantonesefish]

Sorry, I am a little confused, what do you mean by "mix it all at once" ?

 

[rvitko]

With any brand of salt mix, the only way you will get the exact analysis stated by the manufacturer is if you mix the entire portion you purchased at one time. So if you buy a 60 gallon bag, you ideally mix 60 gallons of water in one shot. If you take a portion, say you mix 20 gallons from a 60 gallon mix, you risk having high calcium or high KH or low KH or calcium in that one batch and the remaining 40 gallons of mix will have the opposite problem.

 

[Cantonesefish]

Didn't know that, thanks!

I just bought a box of tunze salt, trying it out. It mixes to about 60 gallons I'm guessing. Unfortunately I can't mix all 60 at once, at least I don't have a mixing tank that large, and would only use it up after a few months.

How would you recommend I store it?

 

[smatter]

I tumble my salt in a bucket to mix it well and what I don't use I pour back into the bag it came in and seal it with a zip tie.

 

[Cantonesefish]

thanks Smatter!

I wonder if it's also possible to make a highly concentrated mix...

 

[rvitko]

I wouldn't recommend a premix of concentrate, the reason being is the salt contains a iodine form that is compounded to an organic, it also has some vitamins, these would degrade quickly so the salt would lose some of its trace elements as a result. Even in the tank these last only a couple weeks but are replenished with trace elements and water changes.

 

[Cantonesefish]

Thanks Roger, how long would you recommend then after mixing to go into aquarium?

 

[rvitko]

A day would be ideal, this gives the KH and CO2 levels time to equilibrate and get the pH stable, but at a minimum 4 hours of vigorous mixing.

 

[mcarroll]

Would you say that active air mixing with a venturi would shorten this interval?

For example, I typically mix saltwater in a 5 gallon bucket (or several) and use a large powerhead (>600 gph) for mixing the water, plus a MaxiJet with the venturi all the way open to mix air in as well.

I only do this for about 20 minutes to an hour though (but don't test for pH). FWIW, KH, Ca, and other parameters do get tested and always seem to be in line with expectation.

Thanks!
-Matt

 

[rvitko]

It might, the main thing you are trying to do besides dissolving the salt is getting the carbonate equilibrium established and this would mainly be determined by the pH, usually fresh mixed saltwater has a very high pH, often 9 or so. It takes dissolving some atmospheric CO2 into the water to get this in line.