Citric Acid

[griss]

I’ve never used citric acid before. I got some old dry (Fiji, Tonga, etc) rock that originally was 1990s wild collected live rock from a friend. I’m wanting to give it an acid bath to reduce potential phosphates.

I don’t want to deal with Muriatic acid and several on here have suggested citric acid. With the cold weather we’re having I don’t think I can do this outside so, can this be done inside? I ask because I see people use it to clean skimmers, kitchen and bathrooms, etc. So, I assume, it would be safe give the rock and acid bath inside????

 

[Uncle99]

I’ve used it for years to clean my wavemakers and gear.
Not as harsh as vinegar, but of course, more expensive.
Works well for me. No issues. Always used inside.

 

[griss]

I’ve used it for years to clean my wavemakers and gear.
Not as harsh as vinegar, but of course, more expensive.
Works well for me. No issues. Always used inside.

Thank you.

 

[wvned]

The problem is this. Muriatic (HCl) acid is a strong acid. Acetic and citric acids are weak ones.
This is based on their chemical properties.
Strong acids completely dissociate in water, producing a high concentration of hydrogen ions, while weak acids only partially dissociate, resulting in a lower concentration of hydrogen ions.
Strong acids will work much more quickly and break down more chemically stable carbonates that weak acids may not work on or may take a month to dissolve.
Yes it takes a bit of care to use and can ruin a shirt in 2 seconds but it I safe enough to be sold by the gallon at Home Depot.

 

[Jimbob]

It seems for your stated purpose, the citric acid should work just fine, and might even be preferred given that is is a weaker acid in comparison to HCI?

As wvned mentions, the stronger the acid, the more quickly it breaks down carbonates... this is ideal when wanting to remove carbonate deposits from equipment. Given you are working with rock and that you only want to "wash" potential phosphates out of your old dry rock rather than dissolve the rock entirely, the weaker acid might be easier to manage?