Did I ruin my rocks?

[Tfish]

I decided to clean a bunch of old dead ”live rock” with citric acid. But without really thinking I did this in the styrofoam box that I was storing them in. I let them be in there for 24 hours with a small pump but now I found them covered with a white substance that I fear is the styrofoam (melted?)
Or could it be just calcium from the rocks (cope?)

It comes right off when I wash it but I’m worried that something has leeched into the rocks that could be harmful longterm?

Picture of a washed one and one out of the bin.

 

[dvgyfresh]

I wouldn’t use those rocks anymore but that is just me

 

[Romeo_Reefer]

Ouch!! From the picture it looks like the styrofoam wall is pitted, if that's the case then it's the foam that's melted.

 

[BryanM]

Don’t know how you can fix that, but I also wouldn’t use them

 

[drewzaun]

Google is not really much help. Citric acid itself won’t melt styrofoam but apparently some of the styrene can be liquified or absorbed into an acidic liquid. The example I saw was lemon juice, which probably is less acidic than the solution you made, if you make it like I do.

Anyway I don’t think that is what the sludge is, but I agree with dcgyfresh, I wouldn’t use that rock anymore.

 

[Tamberav]

Was it on all the rocks? because that brown one looks clean. I would think the Styrofoam would be on all the rock...

I would just rinse/soak and use it, my tolerance is high though, right up there with Paul putting hammers (not the coral, the tool) in his tank.

 

[Tfish]

Was it on all the rocks? because that brown one looks clean. I would think the Styrofoam would be on all the rock...

I would just rinse/soak and use it, my tolerance is high though, right up there with Paul putting hammers (not the coral, the tool) in his tank.

Yeah they were all covered. The clean one is after I washed it off. So they ”look” ok.

 

[Randy Holmes-Farley Verified Community Expert]

I don’t really see a way that styrofoam is decomposed by citric acid in water.

Take some of the white residue you are worried about and put it in citric acid (strong) to see if it dissolves. It may just be powder calcium carbonate.

 

[Randy Holmes-Farley Verified Community Expert]

Google is not really much help. Citric acid itself won’t melt styrofoam but apparently some of the styrene can be liquified or absorbed into an acidic liquid. The example I saw was lemon juice, which probably is less acidic than the solution you made, if you make it like I do.

Anyway I don’t think that is what the sludge is, but I agree with dcgyfresh, I wouldn’t use that rock anymore.

I don’t think that is correct. Polystyrene has no significant solubility in water at any pH

 

[KrisReef]

Acid dissolves arragonite. Like a calcium reactor, too much acid and all your rocks will be mush.

 

[JTP424]

Its the rock, sibling did this with some of their Marco rock. Tried to clean it in a 5 gallon of citric, rock crumbled into mush.

 

[Justdrew]

That is just the rocks that were disintegrating in the acid. I have used muriatic acid/water to clean rocks before and afterwards they were smaller.

 

[Tfish]

I don’t really see a way that styrofoam is decomposed by citric acid in water.

Take some of the white residue you are worried about and put it in citric acid (strong) to see if it dissolves. It may just be powder calcium carbonate.

Ok so update! It pretty much completely dissolved in a glass of water with a lot of citric acid!
Does that mean good to go? (Not holding it against anyone just want professional opinion :) )

 

[Randy Holmes-Farley Verified Community Expert]

Ok so update! It pretty much completely dissolved in a glass of water with a lot of citric acid!
Does that mean good to go? (Not holding it against anyone just want professional opinion :) )

Yes, it just means, as folks have suggested, that it is rock dust and not polystyrene.

Just rinse off what you can and roll forward.

 

[drewzaun]

I don’t think that is correct. Polystyrene has no significant solubility in water at any pH

Apparently so. Further digging reveals it is citric oils that pull styrene into a solution, not the acid, so should be safe, don’t trust the googles

 

[Randy Holmes-Farley Verified Community Expert]

Apparently so. Further digging reveals it is citric oils that pull styrene into a solution, not the acid, so should be safe, don’t trust the googles

Yes, many organic solvents dissolve it. :)

 

[Dan_P]

I decided to clean a bunch of old dead ”live rock” with citric acid. But without really thinking I did this in the styrofoam box that I was storing them in. I let them be in there for 24 hours with a small pump but now I found them covered with a white substance that I fear is the styrofoam (melted?)
Or could it be just calcium from the rocks (cope?)

It comes right off when I wash it but I’m worried that something has leeched into the rocks that could be harmful longterm?

Picture of a washed one and one out of the bin.

Calcium citrate is my guess.