Curing dry rock in RO/RODI vs SW

[Mike N]

I have a lot of dry rock to cure. I would prefer to cure in RODI water to save some cash on salt.
Any advantages to curing in saltwater vs RODI?

 

[redfishbluefish]

Interesting!


The only negative I can think of is that freshwater bacteria will fill the rock and now once placed in saltwater, it will die, and now require a second cure.

 

[Mike N]

Interesting!


The only negative I can think of is that freshwater bacteria will fill the rock and now once placed in saltwater, it will die, and now require a second cure.

Ok, so use salt water for curing, got it.
Lol thanks

 

[reeferfoxx]

You can cure rocks in freshwater. The bacteria will die but the "re"cycling period will be shortened compared to curing dry rock in a DT. Might as well just cycle in saltwater.

 

[CindyKz]

I never understood this. If the rock is dry aren't the bacteria dead anyway?

 

[Mike N]

I never understood this. If the rock is dry aren't the bacteria dead anyway?

Dead yes, but the remnants are still there. As well as those from (once)living organisms on the surface and deep inside the rock.

 

[CindyKz]

Yes, but they aren't going to come back to life so what difference does it make what type water it is? I soak dry rock to leech out phosphate and other nasties left over from the once living organisms you're referring to. Then when I am ready to use it I either add it to my existing system (where existing bacteria will populate it) or I add a source of living nitrifying bacteria to start a new one.

Point being, salt vs. RODI - you can't kill what's already dead.

I am wondering if I am missing a major point.

 

[Mike N]

If I understood @redfishbluefish well enough, the point is that freshwater bacteria will colonize the rock. Which will die off once placed in saltwater, defeating the purpose of curing.

Whereas when curing in salt water, the bacteria stays alive but any dead remnants are washed away. Therefore nothing left to die off once curing is compete.

 

[CindyKz]

I guess what I'm wondering is where the live freshwater bacteria that will supposedly colonize the "dry" rock come from? There would be none in rodi or mixed salt water and everything on the dry rock is dead.

I understand soaking rock to get some of the "bad" stuff out but I don't see how it can have any effect on bacterial population unless bacteria are added in some way....live rock or bacteria in a bottle.

 

[Mike N]

I guess what I'm wondering is where all these bacteria that will supposedly colonize the "dry" rock - fresh or salty - are coming from? There would be none in rodi or mixed salt water.

Gotcha, that question is above my pay grade. I'm curious to know the answer as well.
@Randy Holmes-Farley care to comment?

 

[reeferfoxx]

I guess what I'm wondering is where all these bacteria that will supposedly colonize the "dry" rock - fresh or salty - are coming from? There would be none in rodi or mixed salt water.

Everything around us contains the building blocks to life. I can't exactly remember what its called but the spores for bacteria to colonize are on our bodies.

 

[saltyfilmfolks]

Use old tank water. It has bacteria in it.

 

[Montu]

Isn't curing an entirely different process than establishing a beneficial bacteria colony and completing a tank cycle?

I thought curing dry rock was just letting all the dead stuff fall off and finish decomposing, in this case it doesn't matter what you use...I used water from the hose and a bunch of bleach for 7 days then rinsed everything and finished the cure with a quick Muriatic acid bath, then proceeded to place it in the tank to cycle.

 

[Mike N]

Isn't curing an entirely different process than establishing a beneficial bacteria colony and completing a tank cycle?

Yes it is. This thread is about curing, not establishing biofilter.

 

[reeferfoxx]

Isn't curing an entirely different process than establishing a beneficial bacteria colony and completing a tank cycle?

I thought curing dry rock was just letting all the dead stuff fall off and finish decomposing, in this case it doesn't matter what you use...I used water from the hose and a bunch of bleach for 7 days then rinsed everything and finished the cure with a quick Muriatic acid bath, then proceeded to place it in the tank to cycle.

You are describing cooking the rock. Cure and cycle are essentially the same. Curing would entail more on the aspects of allowing nutrients to build up and then be removed either water changes or algae growth.

 

[saltyfilmfolks]

I would still cure it in saltwater to let the bacteria do the heavy lifting for me.


My coral qt is fallow and I never feed it. It's my first thank now that I've ever seen true zeros. All the "food"has been eaten. To prep to put coral in I have to do weekly water changes in advance and during to make sure it gets fed or the corals die.

 

[reeferfoxx]

I would still cure it in saltwater to let the bacteria do the heavy lifting for me.

+1. Even if intention are to get decomposed matter off before the DT, no matter freshwater or saltwater a cycle will happen. They are one in the same. But with saltwater you can retain the bacteria colony. Cooking the rock is when you do a muriatic, bleach, or lanthinum chloride bath. That would happen prior to curing or cycling.

 

[redfishbluefish]

First off bacteria is the most ubiquitous creature on earth. It is found here, there and everywhere. No introduction is needed, because it's already there. So starting with RO water, bacteria will find its way into the water.

Now let's talk curing. Curing is when the death within the rock leaches out. This is assisted by bacteria breaking down (decomposing) the dead stuff in your rock. So it's best to have saltwater bacteria there since freshwater bacteria would be killed when placed in saltwater, requiring another cure.

To cure, the only thing needed is a little flow. No lights or heater are needed....assuming this is done in a heated room, not in your garage in the middle of winter in Minnesota. Let it stew, and measure nitrates (and phosphates), and do water changes if and when these numbers get high. Note that curing may take a month or two depending on how "dirty" the rock was. You know it's done when N's and P's are no longer rising after a water change.

 

[jda]

There is bacteria in everything that can start to colonize, but this is not whey people suggest curing your dry rock. It is so that some bound terrestrial phosphate, and perhaps dead organic matter, can start to unbind into the water in the container.

 

[Bill from OZ]

Hopefully I can revive this dead thread! I am currently setting up a 40g tank with a 55g sump. I have 40lbs or so of dry rock saved from an old tank. I had bought the live rock off of Craigslist. It came out of a poorly maintained tank.

In my old tank I battled algae for a year while reading 0 on all test kits. I did huge weekly water changes switched water sources, switched test kit brands, ran carbon, dosed vodka, even tried pulling my own hair out to no avail!

Then I discovered RowaPhos. Although my phosphates always read 0, I had a phosphate problem! I had a small clump of bubble algae which acted as my phosphate tester. If it started to enlarge, I knew it was time to change RowaPhos.

Going in, I know that I have a phosphate problem with this now dry rock from that old tank. I Scrubbed it, bleached it, and soaked it in vinegar for nearly two weeks. I've had it in RO water for about three weeks. Today tested phosphates. Before I finished shaking my vial was as dark as possible. So much for cleaning up while I waited three minutes for the results. Over 10 ppm phosphates. I confirmed results and even tested new RO water for 0 phosphates.

Today the rock is going back into RO water until phosphates are 0 for at least 2 weeks. I imagine that more water changes are coming.

In my case it makes no sense to bust into my brand new box of Kent reef mix salt. It will do no good for leaching phosphates. I did not consider the bio load of the decaying freshwater bacteria. Now that I have, I do not believe it will be a significant factor post cycle. If I decide otherwise, I will repeat the bleach, acid, RO rinse before curing/cycling in saltwater.