So you were told your rock leaches phosphates? NOT!

[Randy Holmes-Farley]

@Randy Holmes-Farley Do siporax/marinepure/etc also bind PO4? If they don't do the same thing with phosphate that might be a benefit to using the manufactured stuff with a more minimalist aquascape of rocks (of course they could have their own negatives like marinepure with aluminum).

I do not think they bind much phosphate.

 

[Mrod]

I remember I bought a barnacle rock at the LFS that was in someone’s tank is all I knew at the time. I put it in and noticed some Algea growth increase after some time. Another reefer suggested it may have phosphates so as an experiment I took it out and put it in a bucket of ro water and when tested the next day it had high po4. What I did was keep it in the bucket and put gfo and every week changed the ro water & gfo. It got better over time to the point where I put back in my main tank but if I recall it took almost 4-6 months to get it to 0. It’s been a few years so I don’t recall the actual starting numbers and wish I was in this site then where I could have documented it. Im a believer po4 can be trapped and released unknowingly from rocks.

 

[KrisReef]

"3. Mined rock that has been exposed to terrestrial phosphate in runoff may have a lot of phosphate permeating it. An acid treatment might not be optimal for this as the phosphate may also be deeper inside of it, and treatment in low phosphate water for an extended period might be best."

Acid treatment is not a sure-cure for PO4:

I am planning on changing out my live rock for re-scaping and algae removal in my main tank. I acid washed a collection of live rock (some from other peoples tanks and some I've collected on vacation) and that rock collection has been in a dark barrel for months with a powerhead for circulation. I tested the water (Hanna URL) last weekend. The first test vial turned a beautiful blue that pegged the Checker at flashing 200, somewhere above the meter 200 ppb limit! To retest, I diluted 1ml of barrel water with 10 mls of reef tank water(.03ppm Po4), and used 10mls from that dilution mix to get a calculated 0.14ppm reading from the Checker, which means I had ~14.1 ppm PO4 that had leached from acid washed, bleached, and triple rinsed old tank rock.

I have done two water changes with NSW in the last week, I have not remeasured the barrel water PO4 level, but I am guessing that it will creep up over time as it is probably not exhausted simply by changing water twice.

 

[Will Milberger]

Seeing where this goes...

 

[Randy Holmes-Farley]

What about man made rock, such as Real Reef rock? Do you think man made rock can leach phosphates?

ALL calcium carbonate rock can bind a large amount of phosphate, and it can release it back to the water. There is zero uncertainty in that statement, the issue is only one of what the exposure history of the particular rock is.

Nitrate does not ever bind to calcium carbonate surfaces.

If there is organic material stuck to rock surfaces, it can slowly be released as it breaks down into available N and P.

 

[Randy Holmes-Farley]

deleted

 

[Reefin Dude]

acid bath only removes the P that is attached to the calcium carbonate that was removed by the acid bath. the parts of the structure that are now exposed will still have bound P to it. the acid is not going after the P, it is going after the calcium carbonate. when we acid bath "used" rock it is the outer layers that contain the higher concentrations of P. getting to older parts of the rock hopefully expose less P laden calcium carbonate.

i think that there is some confusion about what is going on. some leaching does occur, but that is not how the majority of the P is removed from the calcium carbonate structure. bacterial action is the primary remover of the P. that is why "cooking" works. the act of "cooking" is not using leaching to remove the P, but the bacteria utilizing the P. the bacterial flock on the bottom of the "cooking" container is the removed P from the calcium carbonate structure.

there is a constant give and take of P between the calcium carbonate and the bacteria. the better the flow around the calcium carbonate structures the lower the local equilibrium level of P.

are links to other forums allowed for additional information?

Adsorption of Phosphate on Calcium Carbonate

Phosphate solubilizing bacteria

Uptake of phosphate ions by calcium carbonate

DYNAMICS AND DIVERSITY OF PHOSPHATE MINERALIZING BACTERIA IN THE CORAL REEFS OF GULF OF MANNAR

G~

 

[ELChingonsReef]

I have a question. So I have been trying to figure out why I've been getting dynoflaglates so often. I have a 1.5 year old tank fully stocked started with dry marco rock from my LFS. I also have a large carib sea rock tower. This was my first time starting a tank with dry rock. I herd it takes longer to cycle but if it was going to help eliminate pests it was worth it to me. Well 1.5 years later I still have pests like vermented snails etc. My point is I think im getting dynoflaglates often because I have a hard time keeping up my phosphate. I have to dose 40 MLS a week to keep phosphate at 0.03 . If the dry marco rock is binding phosphate when it stops will I have a huge explosion of excess phosphate I can't get rid of fast enough? I don't know what would be worse not being able to keep up phosphate or not being able to get rid of them but eventually the rock will reach its limit of phosphate and leach it back into the water column I would think? Am I right ??