Best way to clean dry rock ?

[Yanir34]

Hello , I have 3 medium size dry Indonesian rocks.
I want to clean them before adding to main tank.
What is the best way to do it ?

 

[Randy Holmes-Farley Verified Community Expert]

I recently cleaned some old rock from a previous tank that had been sitting outside for 8 years.

This is what I did:

Garden hose blast outside.
Brush and running tap water in a sink.
Soak in strong bleach solution for a few days.
Rinse well
Soak in ascorbic acid solution for a few minutes each.
Rinse again.
Air dry for a number of days (still had a trace of bleach smell) but its gone after a few weeks.

 

[redfishbluefish]

I have to ask, why ascorbic acid? it's very weak with a relatively low dissociation constant. Why not a more readily available to consumer weak acid?

 

[ajmckay]

I think it depends on how dirty they are... like are they covered in dead stuff or dust?

Dead stuff then yeah hose or pressure washer and a bleach solution but if it's just dust and hasn't been exposed to other chemicals then just a rinse will do IME.

When adding dry rock to a tank I also like to soak them in some nasty water from a water change for a week or two. IME it gives the rock a bit of a biofilm that helps it start growing coralline quicker and keeps them from looking gross and brown. I'm not completely sure why, but that's my experience vs. just tossing in "sterile" dry rock.

 

[areefer01]

I have to ask, why ascorbic acid? it's very weak with a relatively low dissociation constant. Why not a more readily available to consumer weak acid?

If I had to guess maybe less waste? I've read, and to some degree small experience, muriatic acid will remove 10 to 25% of the rock surface area. BRS has a video I think that they did some cleaning of dry rock and weight the rock before, and after. Something along those lines anyway. I cleaned some dry rock and did similar to what RHF did with decent success. Pressure washed, soaking in bleach, etc.

 

[mboley]

I recently bought 90 lbs of Fiji rock that had been sitting dry for a few years. I asked the seller if they had done anything to it before storage and they said no. The rock was white without any noticeable dead stuff so I did no additional cleaning. I cycled it starting 3.5 months ago and still nothing detrimental. I turned on the lights a few weeks ago in an attempt to get some ugly going. I did add a some pieces of live rock and some sand from an existing tank. Apparently that has made a big difference? I don't know. Nitrates have never been higher than 30.

 

[Randy Holmes-Farley Verified Community Expert]

I have to ask, why ascorbic acid? it's very weak with a relatively low dissociation constant. Why not a more readily available to consumer weak acid?

It wasn't intended as an acid, but as a low toxicity antioxidant to deplete the residual bleach in the rock pores.

https://www.fs.usda.gov/t-d/pubs/pdf/hi_res/05231301hi.pdf

 

[redfishbluefish]

If I had to guess maybe less waste? I've read, and to some degree small experience, muriatic acid will remove 10 to 25% of the rock surface area. BRS has a video I think that they did some cleaning of dry rock and weight the rock before, and after. Something along those lines anyway. I cleaned some dry rock and did similar to what RHF did with decent success. Pressure washed, soaking in bleach, etc.

Definitely less waste. Let me begin by stating I'm not a big believer of acid washing rock. I know the intent is to knock off phosphates, but I believe that the phosphates knocked off simply re-attach, while now giving you less rock, especially with hydrochloric. I'm going to guess that ascorbic acid itself binds up that "free" phosphate so it doesn't re-attach to the rock, but that's a guess.

 

[Miami Reef]

It wasn't intended as an acid, but as a low toxicity antioxidant to deplete the residual bleach in the rock pores.

https://www.fs.usda.gov/t-d/pubs/pdf/hi_res/05231301hi.pdf

I probably would have used sodium thiosulfate, but what fun would reefing be if we agreed on everything? :)

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, I intend to describe more fully what I did with these rocks when I start a tank thread, but I was mostly interested in killing off terrestial bacterial that was on them so as to not start off a new tank on the wrong foot. Some were literally buried in soil and a couple had moss growing on them.

I was not trying to remove phosphate or dead tissue since I don't think those are a problem for these very old rocks. There were never in high phosphate water.

 

[Troylee]

Personally I do a muratic acid bath and rinse with my hose! Let it dry over night and throw it in my tank! I’ve done this for years and never had a problem and never saw a rock shrink! As a matter of a fact I’m doing some in the next few days I’m gonna weigh it and prove that brs video is false!

 

[Randy Holmes-Farley Verified Community Expert]

I probably would have used sodium thiosulfate, but what fun would reefing be if we agreed on everything? :)

I'm sure most thiosulfate solutions are fine, but food grade ascorbic acid was not expensive, and I used quite a lot of bleach so didn't want to have to work out how much thiosulfate I might need without leaving a lot of thiosulfate residue in the pores of the rock. Ascorbic acid residue in the pores did not concern me.

 

[areefer01]

Personally I do a muratic acid bath and rinse with my hose! Let it dry over night and throw it in my tank! I’ve done this for years and never had a problem and never saw a rock shrink! As a matter of a fact I’m doing some in the next few days I’m gonna weigh it and prove that brs video is false!

Lol - slow down all for reef newbie!

Teasing of course. If I remember correctly BRS test was over multiple weeks as they focused on phosphate in dry Pukani. I think it was natural, acid, bleach, and acid/bleach 2 step. Anyway as if you don't already know the test won't be the same and soak time may be the reason they noticed the difference.

Hope all is well!

 

[Troylee]

Lol - slow down all for reef newbie!

Teasing of course. If I remember correctly BRS test was over multiple weeks as they focused on phosphate in dry Pukani. I think it was natural, acid, bleach, and acid/bleach 2 step. Anyway as if you don't already know the test won't be the same and soak time may be the reason they noticed the difference.

Hope all is well!

Haha! It’s great! lol… yeah everyone references that video and it crazy to me! I fill half a 40gallon brute with water “20 gallons” and throw my rocks in there and pour a gallon of muratic acid in and when it quits foaming after about 30-40 minutes I drain it and hose everything out well and let it dry over night! Good to go and the rocks look the same exact same size but sparky white again and zero issues with phosphates or algae in my experience..

 

[Miami Reef]

I'm sure most thiosulfate solutions are fine, but food grade ascorbic acid was not expensive, and I used quite a lot of bleach so didn't want to have to work out how much thiosulfate I might need without leaving a lot of thiosulfate residue in the pores of the rock. Ascorbic acid residue in the pores did not concern me.

Is there not a sink for sodium thiosulfate in a cycling tank?

Wouldn’t an RO/DI bath suffice for diluting the sodium thiosulfate pores?

 

[Besieged]

For the rock recently taken from a taken that leaked that I picked up, I scrubbed and sprayed the rock off to remove as much detritus as possible, and then put it in a large tote or plastic trash barrel, and added 1 cup of sodium percarbonate (the core ingredient in "OxyClean") per ~10 gallons of water.

Sodium percarbonate breaks down into H2O2 in water, acting as a non-chlorine bleach and dissolving organics.

I let it sit for 24-48 hours, occasionally agitating the tub/barrel and turning pieces over.

For the pieces that needed extra bleaching, I re-rinsed and scrubbed, and put them into a shallow container for a second pass, ensuring that they got plenty of sun: H2O2 and UV combined significantly accelerate bleaching action. My wife's family does carpet cleaning and disaster remediation, and they tell me many fancy rug owners found this out to their dismay when they used "OxyClean" on their rugs and don't get it all out, and then the places the light touches it bleaches RAPIDLY.

Once it's clean to your satisfaction, empty out the H2O2 water. Rinse/scrub thoroughly again. Put back in the bucket and add 10mg of ascorbic acid (aka Vitamin C) per gallon of tapwater: ascorbic acid breaks down chlorine and chloramine through a redox reaction, resulting in soda ash, CO2 and hydrochloric acid (which breaks down immediately in water to harmless chloride ions): chloramine, however, if present, will also produce ammonia, which in this case is fine since we're going to let it dry in the sun and rinse it at least once more.

Let it rest in the bucket of dechlorinated water a few hours, agitating it once in a while, then empty, and let dry in the sun for at least a few days.

Do a final scrub and rinse in RO/DI or distilled water. If you have any lingering concerns about ammonia, add some SeaChem Prime or similar to the rinsing bucket just to make sure.

After that, you're good to go!

(After first rinse and sorting, to cleaning, to what I was working with just last night.

I was grateful I could not smell what the rock was cooking...)

 

[vandy]

Take a power washer to the rocks if they are filthy. Then grab a scrub brush and go to town. Then you can cure if you want (I use bleach).

 

[JCOLE]

Haha! It’s great! lol… yeah everyone references that video and it crazy to me! I fill half a 40gallon brute with water “20 gallons” and throw my rocks in there and pour a gallon of muratic acid in and when it quits foaming after about 30-40 minutes I drain it and hose everything out well and let it dry over night! Good to go and the rocks look the same exact same size but sparky white again and zero issues with phosphates or algae in my experience..

This is exactly what I do as well. I actually have some in a rubbermaid can tonight. I let the acid run until the carbonate weakens the acid on it's own. I do this to brand new dry rock out of the box as well. It does a great job of cleaning out all of the fine aragonite dust and really opens up the rock.