Muratic Acid

[Omgitsjoe]

Due to a doser mishap my ALk spiked from a stable 8.5 DKH to 14 DKH. (running triton method BTW) I stopped dosing everything. Its been about 1.5 weeks and my ALK seems to have plateaued at 10.5 DKH. Despite not dosing anything it doesnt seem to be going any lower. My plan is to lower it using Muratic acid, aerated in fresh mixed saltwater and use that for a water change.

Now to the question for you math nerds.

How much muratic acid and how big of a water change? Total volume is 75 Gallons. I would like to lower it back to 8.5 DKH.

Muratic Acid I plan on using:
https://www.homedepot.com/p/Klean-Strip-1-gal-Green-Muriatic-Acid-GKGM75006/202690263

 

[Randy Holmes-Farley Verified Community Expert]

I discuss how to lower alkalinity in these threads:

Sodium Bisulfate to Reduce Alkalinity in New Salt Water or in Display Tanks
https://www.reef2reef.com/threads/s...in-new-salt-water-or-in-display-tanks.362825/

Reducing alkalinity ?
https://www.reef2reef.com/threads/reducing-alkalinity.339109/#post-4214464

 

[Randy Holmes-Farley Verified Community Expert]

The green stuff is diluted muriatic acid so you will need more than the thread states.

 

[Omgitsjoe]

Geez.... you need a Phd to decipher that math lol

 

[LC8Sumi]

I wouldn’t bring HCl close to an online reeftank. Can you not do water change(s) instead with a lower alk salt?

 

[Omgitsjoe]

I wouldn’t bring HCl close to an online reeftank. Can you not do water change(s) instead with a lower alk salt?

Why not? Please elaborate

 

[Fourstars]

10.5 is fine. I would just leave he tank alone. It will come down in time

 

[Randy Holmes-Farley Verified Community Expert]

I would not add it to a reef tank either. The pH drop is big. I mistakenly thought we were talking about new salt water.

 

[Idoc]

I would do a water change...how much alkalinity is normally in your salt mixture? Then, I would let it come down naturally.
Muriatic acid is kind of harsh for a drastic drop! I used that stuff to clean pumps and rock....I don't like messing with it.

 

[Omgitsjoe]

I would not add it to a reef tank either. The pH drop is big. I mistakenly thought we were talking about new salt water.

We are talking about a water change. Im mixing it in a bucket, aerating it then doing a water change

 

[LC8Sumi]

I don’t understand the need for HCl? Are you trying to do a bucket of freshly mixed salt water with very low alk (precipitate out CaCO3 in it & not addig that to the tank?) How big is the system? Ah okay I see it’s 75g. I don’t know. It’s kind of risky IMO to get it right & not to drop the alk (and Ca) too much. I’d buy a small bucket of RS blue bucket & do some WC’s with that as-is

 

[Omgitsjoe]

I don’t understand the need for HCl? Are you trying to do a bucket of freshly mixed salt water with very low alk (precipitate out CaCO3 in it & not addig that to the tank?) How big is the system?

Yes. plan was to do a 10 gallon water change with low DKH fresh salt water.

 

[LC8Sumi]

Yes. plan was to do a 10 gallon water change with low DKH fresh salt water.

Edited my quoted post since

 

[Omgitsjoe]

If I understood @Randy Holmes-Farley post (in different thread) that is what he recommends to safely lower the DKH

 

[LC8Sumi]

If I understood @Randy Holmes-Farley post (in different thread) that is what he recommends to safely lower the DKH

He’s the Jedi of reef chemistry, so better to listen to him:)

(my main concern with HCl are two things: it can drop the pH super mad - like 10ml in 10g (freshwater) could result in something like pH2. Probably saltwater is different and all the buffers prevents this, but still. The other issue with it is that it is just so easy to break off that Cl atom and burn your lungs badly)

sorry bout my comments not being useful.

 

[Randy Holmes-Farley Verified Community Expert]

We are talking about a water change. Im mixing it in a bucket, aerating it then doing a water change

then I’m good using it to drive down alk as low as you want, but not below zero where it becomes acidic and will lower tank pH even after aeration.

 

[Omgitsjoe]

then I’m good using it to drive down alk as low as you want, but not below zero where it becomes acidic and will lower tank pH even after aeration.

How long does it need to aerate?

 

[Omgitsjoe]

So I just mixed up 10 gallons of fresh salt water. Added 10Ml of the green muriatic acid. Im going to wait a bit and check the PH and DKH of it. How much of a drop should I expect on my display after I do the 10 gallon water change?

 

[Randy Holmes-Farley Verified Community Expert]

How long does it need to aerate?

hard to say since it depends on how effective it is and if the room air is fresh, but overnight will be pretty good

 

[Randy Holmes-Farley Verified Community Expert]

So I just mixed up 10 gallons of fresh salt water. Added 10Ml of the green muriatic acid. Im going to wait a bit and check the PH and DKH of it. How much of a drop should I expect on my display after I do the 10 gallon water change?

I haven’t done the math to know the alk in that water. The result is the weighted average of the two. If it was a 20% change of 0 dKH and 80% 10 dKH, final alk is 8 dKH