Ratios for acid bath?

[Daniel@R2R Verified Admin]

Hi guys, I'm getting ready to acid bathe some rock. What ratio do you recommend? I've seen 10:1, 20:1, and even 4:1.

Also, should I use a shallow tub? Trash can? Does it matter?

 

[Daniel@R2R Verified Admin]

It's a LOT of rock (300lb or so). I'm thinking I can get it all in my 50 gallon trash can (maybe...if I'm careful about placing it), but is it a bad idea to stack pieces?

 

[Humblefish]

I've always done 10:1 for 10-15 mins. A small, shallow plastic kiddie pool works best for lots of rock IME. Remember to wear rubber gloves, protective clothing, face mask, eye protection, etc.

 

[Daniel@R2R Verified Admin]

I've always done 10:1 for 10-15 mins. A small, shallow plastic kiddie pool works best for lots of rock IME. Remember to wear rubber gloves, protective clothing, face mask, eye protection, etc.

A kiddie pool! That's a great idea! Thanks!

 

[kschweer]

Also remember always add the acid to the water not water to the acid. Also be sure to have baking soda on hand to stop the Reaction and neutralize the acid when your done bathing it.

 

[Daniel@R2R Verified Admin]

Also remember always add the acid to the water not water to the acid. Also be sure to have baking soda on hand to stop the Reaction and neutralize the acid when your done bathing it.

Right! I am definitely planning to add the acid last. I'm figuring I can dilute with a water hose after I'm done. I was planning on leaving the rock in the acid bath for a while (an hour or so), so I figure it will pretty much be neutralized anyhow. I also didn't take any chances...bought sleeve length gloves. LOL

 

[Humblefish]

Right! I am definitely planning to add the acid last. I'm figuring I can dilute with a water hose after I'm done. I was planning on leaving the rock in the acid bath for a while (an hour or so), so I figure it will pretty much be neutralized anyhow. I also didn't take any chances...bought sleeve length gloves. LOL

If you're gonna go an hour, might wanna do a 20:1 ratio instead. 10:1 eats away at the rock pretty fast.

 

[fab]

Which acid do you use? And at what % concentration is it before you dilute it?

Also what kind of rock are you treating?

 

[mfinn]

I used 2 cups of muratic acid to 5 gallons of water

 

[Daniel@R2R Verified Admin]

Which acid do you use? And at what % concentration is it before you dilute it?

Also what kind of rock are you treating?

Muriatic acid. I got it from Home Depot. Not sure of the %. I'm thinking it's the standard stuff. The rock is a mix of tonga, pukani, florida reef, etc...

 

[fab]

So this is the real stuff, originally from the ocean. What is your goal for the acid bath? How long do you bathe the rock? What damage do you expect to see to the rock itself from this bath?

 

[Daniel@R2R Verified Admin]

So this is the real stuff, originally from the ocean. What is your goal for the acid bath? How long do you bathe the rock? What damage do you expect to see to the rock itself from this bath?

Removing the organics from the outer layers of rock (the acid will dissolve the outer layer of a few millimeters). It should aid with phosphate and resulting algae issues when I use it in my next reef. I don't anticipate any damage to the rock really. It'll be a few millimeters smaller, but I doubt it will be super noticeable. From everything I've read, it'll be a little lighter and bare.

 

[fab]

How should it benefit through the reduction of phosphate? Is the phosphate supposed to be some kind of surface coating that the acid bath will remove? I thought that phosphate would permeate the rock through and through such that after removing the surface layer of rock phosphate would continue to leach into the water at the same or similar rate.

I understand that Pukani rock has a reputation as a phosphate source by leaching. How about the other rocks in your mix?

I do get the stripping of organic matter.
fab

 

[Daniel@R2R Verified Admin]

How should it benefit through the reduction of phosphate? Is the phosphate supposed to be some kind of surface coating that the acid bath will remove? I thought that phosphate would permeate the rock through and through such that after removing the surface layer of rock phosphate would continue to leach into the water at the same or similar rate.

I understand that Pukani rock has a reputation as a phosphate source by leaching. How about the other rocks in your mix?

I do get the stripping of organic matter.
fab

The reason for me has to do with getting it clean primarily, so the acid bath will remove everything that's on that outer layer. From what I've read on this, the question of leaching phosphates primarily has to do with where the rock came from. If it came from the ocean, then it's likely that the outer layer of most rock is the source of any phosphate issues, but if it was buried, it may have issues with having phosphate throughout that will leach back into the water.

So, my plan is to start with the acid bath and then cure it for a bit before I use it.

 

[Randy Holmes-Farley Verified Community Expert]

The concentration is not very important. The concentration drops as the acid reacts with the rock, so more rock to water ratio means you need more acid. I usually recommend about 1 part acid added into 10 parts fresh water.