Ocean rock discoloration

[RedSeareefkeeper]

Hello,
I have just finished bleach curing some ocean rock, I had bought it after it was sitting outside for quite a while and was heavily discolored so I opted to let it sit in bleach for 2 weeks instead of the usual week. The bleach dip succeeded in removing tons of grayish brown muck from the rocks that would have otherwise gone into my tank not to mention all the potential spores and whatnot, and this is just what was washed off! There was like half an inch of this stuff in the other container I had the rocks in!


The problem is that although it did make the rocks cleaner they still have a few issues with odd colors on them that I'd like to know whether or not they are a problem.

Issue no.1: this rock has a big rusty red stain on it with an area that is almost blacked out, I don't know what it is (but I certainly would like to know what!) But I don't think that despite the coloration it is infact a rust stain considering it looks to have spread more like an encrusting growth would or like something was spilled on it, when I first got the rock the black area was definitely bigger meaning this stuff was atleast partially removed by the bleach which to me is another indication this stuff whatever it is, is organic in origin.

Tips or thoughts on how to remove this or should I worry about it at all?

Issue no.2: all the rocks still have a brownish look to them that is the same shade as the aforementioned muck but with a slightly purplish tinge, could this just be dead coraline algae that has been discolored by bleach? If it's of no health concern I'll just leave it be as it isn't as garrish as the "rust" stain and will be covered by a million new encrusting thingies in no time.

Again, any thoughts or comments on what it is or should I get rid of it and if so, how?

Sincerely RedSeareefkeeper,

 

[RedSeareefkeeper]

One idea of mine that I just thought of after posting this: concentrated bleach directly to the rust spot or would that do nothing?

 

[Reefing102]

Issue two, I likely wouldn’t be concerned with.

Issue one, while I’ve had multiple colors on rocks, can’t say I’ve seen much rust look. If you really want to get it clean I’d look into a Muriatic Acid bath. For reference back in 2015 @Randy Holmes-Farley reccomended this:

Acid treatment of live rock is a good way too strip off the outer layer, removing phosphate, copper, organics, and other undesirables that might be on it.

I typically recommend 1 part acid diluted into 10 parts water.

That said, I think the general procedure (I can’t find the instructions currently) is people soak for about 1 hour, then use baking soda to neutralize the acid and then soak in freshwater for a few days

Edit to add: found this -



If you go this route, use proper safety precautions when using strong acids

 

[Mr. Mojo Rising]

did you have a powerhead in the bleach bucket? From how you mention it was "left outside", I would suppose no powerhead so no circulation in the water.

The water flow helps remove the tougher stains. I even move the powerhead around after a couple of days so the flow can hit other rocks.

I don't know how much bleach you used, but I'm not shy with it, I add about half of a 2 litre bottle sometimes, depends how dirty they are. Sometimes I dump the water out after a week and start with new water and new bleach. Depends again how dirty they are.

I've never tried the muratic acid, I'm too clumsy to even think about messing around with acid.

 

[RedSeareefkeeper]

did you have a powerhead in the bleach bucket? From how you mention it was "left outside", I would suppose no powerhead so no circulation in the water.

The water flow helps remove the tougher stains. I even move the powerhead around after a couple of days so the flow can hit other rocks.

I don't know how much bleach you used, but I'm not shy with it, I add about half of a 2 litre bottle sometimes, depends how dirty they are. Sometimes I dump the water out after a week and start with new water and new bleach. Depends again how dirty they are.

I've never tried the muratic acid, I'm too clumsy to even think about messing around with acid.

I have a spare powerhead, I'll go and put the "rusty" rock in a bucket with a higher ratio bleach solution and a powerhead pointing at it and see how it is in 1 week

 

[RedSeareefkeeper]

Issue two, I likely wouldn’t be concerned with.

Issue one, while I’ve had multiple colors on rocks, can’t say I’ve seen much rust look. If you really want to get it clean I’d look into a Muriatic Acid bath. For reference back in 2015 @Randy Holmes-Farley reccomended this:


That said, I think the general procedure (I can’t find the instructions currently) is people soak for about 1 hour, then use baking soda to neutralize the acid and then soak in freshwater for a few days

Edit to add: found this -



If you go this route, use proper safety precautions when using strong acids

I think the acid will do a good job just I don't want to use it unless all else fails, will update on what works

 

[mfinn]

I would do a second bleach bath.
Bleach becomes less effective with contact with air over time.
After the first week, all you probably had left was the smell.

 

[RedSeareefkeeper]

I would do a second bleach bath.
Bleach becomes less effective with contact with air over time.
After the first week, all you probably had left was the smell.

I know, I added a second dose after first week

 

[RedSeareefkeeper]

Update:
I put the rock back in for another week this time with powerheads in the bucket pointing at it, didn't help at all sadly all it did was turn the suction cups on the cheap powerheads into sludge. Luckily my LFS will partially refund the rock, I don't want to mess around with acid over a rock that I didn't end up using for my aquascape that I finished in the meanwhile.