Bleach cure dried live rock

[reefer10]

Ok so I did a SUPER long bleach cure. Forgot about the bucket for several months. It was dried live rock. The rock in question I believe was from Jakarta. It had a lot of organics on it. After the long bleach cure I saw some black stuff on the rock, maybe was there before. So I did another bleach cure a couple times, more correct timeframe. Black is still on the rock. It is smooth and does not scrub off. Almost like black coralline. Other ricks in the same container did not have this happen. Couldn’t be mold right lol?

 

[reefer10]

I thought for a bit it was the rubber from the suction cups on the pump that had disintegrated a little and deposited, but it won’t scrub off with a toothbrush. Should I do one more stronger bleach bath, like almost 50/50 bleach water?

 

[Dan_P]

I thought for a bit it was the rubber from the suction cups on the pump that had disintegrated a little and deposited, but it won’t scrub off with a toothbrush. Should I do one more stronger bleach bath, like almost 50/50 bleach water?

The rock looks like it needs to have its surface dissolved off with acid

 

[reefer10]

The rock looks like it needs to have its surface dissolved off with acid

Ok, should it still be safe to use like this? Acid bath just for visual purposes.

 

[Dan_P]

Ok, should it still be safe to use like this? Acid bath just for visual purposes.

That I can’t answer. No idea what has soaked into the rock surface.

 

[reefer10]

Ok, should it still be safe to use like this? Acid bath just for visual purposes.

Citric acid good to use?

 

[reefer10]

The rock looks like it needs to have its surface dissolved off with acid

Citric acid good to use?

 

[Dan_P]

Citric acid good to use?

Might be slower than hydrochloric acid but much safer

 

[reefer10]

Might be slower than hydrochloric acid but much safer

Thanks for the help! So would you prefer citric acid or vinegar?

 

[xabo]

May be worth a read: https://www.bulkreefsupply.com/cont...-with-acid-for-a-saltwater-aquarium-reef-faqs

 

[Randy Holmes-Farley Verified Community Expert]

It is possible the black is metal sulfides. Removing it seems prudent to me.

 

[Dan_P]

Thanks for the help! So would you prefer citric acid or vinegar?

No preference. I think citric acid is more acidic and doesn’t have an odor. Since I always have vinegar around, I probably would give it a try to see what happens,

 

[reefer10]

No preference. I think citric acid is more acidic and doesn’t have an odor. Since I always have vinegar around, I probably would give it a try to see what happens,

What ratio would you use?

 

[reefer10]

It is possible the black is metal sulfides. Removing it seems prudent to me.

I was wondering, or some of the sluffed off rubber from the suction cups, being in the bleach so long.

 

[Dan_P]

What ratio would you use?

I would start with full strength vinegar.

 

[Randy Holmes-Farley Verified Community Expert]

Well, I hadn't thought it might be rubber bits, but if it might, that won't dissolve in the acid (though it might lift off).

 

[reefer10]

I would start with full strength vinegar.

For how long? Certain % to look for on bottle?

 

[reefer10]

Well, I hadn't thought it might be rubber bits, but if it might, that won't dissolve in the acid (though it might lift off).

It doesn’t come off with brush so. You think citric acid or vinegar is goood enough if metal sulfides?

 

[Randy Holmes-Farley Verified Community Expert]

It doesn’t come off with brush so. You think citric acid or vinegar is goood enough if metal sulfides?

If neither acid, bleach, nor a brush remove it, I'd probably not worry about it.

 

[Dan_P]

For how long? Certain % to look for on bottle?

Vinegar is about 5% acetic acid.

I think you have to play this by ear. Pour some on the black surface. Does it bubble? Does the surface look whiter? If nothing happens soak it go overnight.m