Why do you circulate dry rock in salt water?

[User1]

What do you mean by this? I'm not angry. I'm curious and trying to be specific. I ask lots of questions, because in my experience if you are not certain what everyone in the room is talking about, things get missed and in medicine this is a bad thing. It's just the way I am. I feel like I understand the nitrogen cycle and introduction of bacteria into a tank system. Maybe I don't and I'm open to that. I feel like that is a completely separate issue than curing rock. Again, maybe not. Perhaps I should have defined things the way I understand them, which is fair.

For me:

Curing: The process of removal of organics from rock to help alleviate algal and diatom blooms in a tank.
Cycling: Introduction of bacteria into a system specifically for the breakdown of ammonia and nitrite.

I was not under the impression that bacteria helped remove phosphate from the system, but it was mentioned in a post above.

I was initially asking whether MacroRocks had organics, which makes sense they do. Moving on from that was the way in which salt water helps remove the organics. I'm not trying to challenge the status quo, just wondering why.

The reason I ask here is because when I google search it was too specific of a question and did not get any appropriate hits.

Didn't mean to imply you are angry - apologies. Just how it came across to me when I read I AM NOT parts. No worries. I think you probably got what you are looking for judging by some of the responses. With regards to removing phosphate I did that using LC and freshwater as I noted earlier. I threw in a power head and let it sit in 24 hour sessions. Rinse and repeat. The more baths/sessions you do the better chance you will have of lowering it. Few even use LC after the cycle to lower in combination with filter socks. Few videos out there.

 

[texdoc77]

Didn't mean to imply you are angry - apologies. Just how it came across to me when I read I AM NOT parts. No worries.

Of course, no worries, it is hard to convey tone and I don't use a lot of emojis.

I think you probably got what you are looking for judging by some of the responses.

Well, not really. I believe that NaCl and LC work, but what I want to know is how. How does the saltwater chemically help get rid of the phosphates from the rock. How does LC chemically work. Maybe it is not known, which is why I am asking. Maybe I should head over to the chemistry forum and see if any of those guys have a thought.

I really really do appreciate everyone that responded. This is such an active forum. If anyone else has a thought please let us know. Otherwise I may try over in Chemistry.

 

[jda]

Aragonite binds phosphate. Your dry rock will have some bound... maybe a little, maybe a lot and you will not know until you get it. Even rocks from the same store/place have different levels in different batches... it just depends on how much terrestrial phosphate was near the rock when they were in their natural spot.

The rock will unbind better with more salinity. Chemistry - I don't know why, but Dr. RHF said so and I believe him. Saltwater works better. Heat will also help this - get it up to 80-84 to speed things up (assuming no livestock).

The rock will unbind some phosphate in the fresh saltwater and some phosphate will enter the water column. This is when you can dose some Lan Chloride and export some of the phosphate that is in the water column. When the water gets low, the rock will unbind more. Lather, rinse, repeat until you are happy with the phosphate concentration. Then you are done.

Some things to consider with aragonite and phosphate binding. Rocks will bind/hold much more than the water level, but they do bind to somewhat of an equilibrium. It will take a few days the first few times that you lower the water level, but then it can take long as phosphate from the interior of the rock takes longer to work it's way out.

 

[NowGlazeIT]

brand new never been in a tank dry MacroRocks


SC

The only clean rock, is one that came fresh and live from a trusted source. I have a rule of thumb to rinse anything dry going into my display. Mainly for dust or machine oil

 

[mtfish]

Lanthanum binds the phosphate with the following formula. I want to precipitate Phosphate from tank water in a marine aquarium. LaCL3 + PO4(-3) -> LaPO4 (insoluble crystals)

 

[Admann]

I'm thinking if you use freshwater to cure, it will take considerably more time for the saltwater to exchange the freshwater in the rock to create the environment (cycle) necessary for saltwater bacteria to live. Run on sentence, I know.

 

[texdoc77]

Sorry to bring this back up but I never really got a good answer yesterday and kept plugging away. Many of you were correct in saying that the organics are removed better in salt water. I figured this, but wanted to know why. A few ventured guesses and I will not quote the wrong ones, but in order for all to have better information going forward here is the main issue - and, no, it does not have anything to do with bacteria, sorry.

It's a little thing called the Stetschenow constant. This is basically a chemical reaction that causes organics to dissolve better in NaCl than without. The constant is different for each organic compound, salinity and temperature. This means that organics will unbind from the rock they are on and enter the salt solution where they can be taken out, as many of you suggested. The how is a little more complicated and I will quote the Research article which originally appeared in Marine Environmental Research in Dec 1997, Vol 44, Issue 4, pgs 429-444, by Xie, et al.

"The hydrophobicity of organic solutes is therefore increased by this factor (stetschenow constant), as is the air-water partition coefficient, implying an increased partitioning from aqueous solution into air, organic carbon and lipid phases. The effect must be quantified when comparing the behavior of organic contaminants in freshwater and marine conditions."

So now I know, and so do you.

 

[Admann]

Kind of like the same thing when brining a turkey.

 

[ScottB]

OK. Unless someone else wants to share an experience/experiment, I will play guinea pig. I just built a structure out of Marco rock. About 30 chunks are glued together here to a base rock that is suspended on 1/2 acrylic rods. Not a great pic, but there are 16 landing pads for gluing SPS and LPS. Many beers went into this creation. I think I have found my true calling finally

I will drop it in vat, circulate/salt/heat/dark and Hanna test the water after a week or so for PO4 and let you know what I find. You all give me a bunch of Like & Loves so I can feel vastly but temporarily more popular. Deal?

So after a two week bath in new salt water -- heated & circulated -- I tested using Hanna ULR Phosphorus Checker and got a 5 which translates to .0153305 ppm.

What I did NOT do, was test the new water (IORC) before immersion. Still, it is safe to say that at least my sample of Marco Rock does not harbor significant amounts of PO4.

 

[CindyKz]

According to Marco Rocks' FAQ, it is "safe to use out of the box". Where do they recommend circulating it in salt water?

I haven't used the "Marco rocks" brand but have used similar, Florida mined rock from ReefRocks. I've added small pieces to existing tanks several times after just a quick rinse. No issues. I've never set up a brand new tank with 100% dry though, which would probably be much different.

 

[Cell]

You can use freshwater to cure old rock, ie get rid of all the dead organic matter, let phosphate leach etc...But if you want to make it "live" rock and grow nitrifying bac, then you need saltwater.