Lowering DKH In Newly Mixed Salt Water

WVReefJunkie

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I am using IO salt, and wanted to lower DKH to 8.4, what additives can you add to your new salt mix to lower it? Also is there any calculators for this, and any risks to livestock? Thanks
 

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I am using IO salt, and wanted to lower DKH to 8.4, what additives can you add to your new salt mix to lower it? Also is there any calculators for this, and any risks to livestock? Thanks

 

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I would have to recheck it. My display is 315 gallond with a 100 gallon sump. I did a 50 gallon water change today and my dkh went from 8.4 to 8.78

If you mix to .35ppt in salinity, the newly mixed IO water should test at about 10 dKH or slightly above.

Also
Making sure you have a good refractor meter (for salinity) and use a .35 solution to calibrate it with.
 

RobertTheNurse

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I would have to recheck it. My display is 315 gallond with a 100 gallon sump. I did a 50 gallon water change today and my dkh went from 8.4 to 8.78
That's still not a bad level. How long have you been using this salt for? And more importantly how I'd the tank doing? What do you have stocked in it. And got pics?
 
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I have about ten sps frags and some euphyllia. I just dont like turning my 2 part dosing off to lower my dkh after water changes.
 
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That's still not a bad level. How long have you been using this salt for? And more importantly how I'd the tank doing? What do you have stocked in it. And got pics?
I have been using that particular salt since I started my new system. It was a lower cost salt compared to others, thats the reason for it.
 

RobertTheNurse

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If it ain't broke. Don't fix. Dkh in 8-9s imo is not a bad level. I'm on the lower side currently 7.7, I've just started to dose. If you have SPS and LPS it's going to suck out your dkh level and calcium. Makes no sense to me to lower it, when once things grows it will naturally lower, and then you'll want to start dosing.
 

Courtney Aldrich

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I am using IO salt, and wanted to lower DKH to 8.4, what additives can you add to your new salt mix to lower it? Also is there any calculators for this, and any risks to livestock? Thanks
Your system is (415 gallons = 1535 L). To lower by 1 DKH, you would need to dose about 0.27 moles of a monoprotic acid (like hydrochloric acid = muramic acid, or acetic acid). I would suggest citric acid since this contains three equivalents of acid per molecule and is available from many suppliers as a food grade solid. For citric acid you would need 0.091 moles x 192 grams/mole = 17.5 grams. Make sure to buy citric acid and not sodium citrate. I would dose slowly in small portions. The citrate acid will quench alkalinity and serve as a carbon source like vodka or vinegar.
 

Randy Holmes-Farley

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Do not use citric acid or any organic acid. It will just be metabolized and the alkalinity all comes back.

Here are my two recommended recipes for lowering alkalinity in new salt water:


 

Randy Holmes-Farley

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Your system is (415 gallons = 1535 L). To lower by 1 DKH, you would need to dose about 0.27 moles of a monoprotic acid (like hydrochloric acid = muramic acid, or acetic acid). I would suggest citric acid since this contains three equivalents of acid per molecule and is available from many suppliers as a food grade solid. For citric acid you would need 0.091 moles x 192 grams/mole = 17.5 grams. Make sure to buy citric acid and not sodium citrate. I would dose slowly in small portions. The citrate acid will quench alkalinity and serve as a carbon source like vodka or vinegar.

I don't believe it is a good plan to use a metabolizable organic acid, like vinegar or citric acid. When bacteria metabolize the acetate or citrate, the alkalinity all comes back.
 
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I don't believe it is a good plan to use a metabolizable organic acid, like vinegar or citric acid. When bacteria metabolize the acetate or citrate, the alkalinity all comes back.
Thanks Randy, I am currently switching my salt from instant ocean to Fritz RPM salt to try to maintain a DKH of 8.5. I post my results, I will look into adding the other, thanks!
 

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I don't believe it is a good plan to use a metabolizable organic acid, like vinegar or citric acid. When bacteria metabolize the acetate or citrate, the alkalinity all comes back.
Sorry for the bad suggestion. I hadn't thought this far ahead and thought I was being clever with citric acid.
 

Randy Holmes-Farley

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Sorry for the bad suggestion. I hadn't thought this far ahead and thought I was being clever with citric acid.

No problem. It's good to have more chemists around. :)
 

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