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So we all need to buy phosphate media but the fish stuff is a rip. I want to buy 40 pounds of it and split it up. This is the commercial grade stuff they use in pro setups. GFO etc. costs 50-60 bucks a pound. This would be 3.75 a pound! We have to order 300 bucks worth of it. Who needs some phoslock! I will commit $50 bucks take care of the order etc.



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Its used in lakes and large ponds, but i couldn't find any data if it is reef or saltwater safe. GFO has been in use in reef tanks for many years and its safety has been well studied. Phoslock is a completely different chemical. You don't know if its going to be toxic to any of the corals, or if it will change your water chemistry in any other way (hundreds of possibilities... it could deplete oxygen, change viscosity, change pH, change alkalinity, precipitate out major elements or trace elements, mess up your skimmer...). Without proper experimentation, and without first hand experience of hundreds of other reefers, I would be very careful of introducing an unknown chemical into my reef tank... even if the company claims its marine safe.

You may be confusing it with marine products like this: http://www.marinedepot.com/PURA_PhosLock_GFO_Phosphate_Removal_Media_150_gram_Phosphate_Remover_Chemical_Filter_Media-Magnavore_%28PURA%29-MN3111-FIFMCHPR-vi.htmlwhich are basically just higher quality GFO. Same chemical composition. The Sepro stuff is something else.

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Researching now.

The phosphorus bond with Phoslock (lanthanum) is permanent. Solution based lanthanum products can be dangerous due to free floating lanthanum but this is bound to media so should be much better. Probably great for curing live rock etc. at the very least. My father is a chemist so I have him on the job for possible side effects in salt water :) It is very simple chemistry at work here.

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Adding LaCl3 directly to the fish tank is not a good idea Therefore, I thought you might be interested in these articles:. http://www.phoslock.eu/media/7464/lanthanum-and-human-toxicity.pdf, http://www.phoslock.eu/media/7407/Eco-toxicity-Assessment-Report-May-2009.pdf which describes the human and fish toxicity of a La/clay complex in the form of granules (http://www.phoslock.eu/en/phoslock/about-phoslock ) that was developed by an Australian agency to control algae growth in commercial fish farms by reducing the available phosphate through the formation of highly insoluble LaPO3. The Ksp is so small you wouldn’t have to worry about it (see below at bottom of e-mail.

If you want to get sophisticated you could place the granules in a pumped flow through cylinder capped at each end with a particle filter of your choosing. Or you could use a “media reactor” which is another form of a fluidized bed. As the aquarium water flowed through the filter the formed lanthanum phosphate would probably remain absorbed on the clay/La granules. Any unbound lanthanum phosphate particulate could be stopped by the filter caps. Once the filtration column was exhausted (as measured by the appearance of soluble phosphate in the bulk aquarium water) you could just empty out the saturated material and recharge.

You can buy it on the internet. http://www.forestrydistributing.com/en/phoslock-phosphorus-locking-granules-technology-sepro.

You can also get an iron based absorbant GFO (Beta-GFH (Beta Ferric Oxide Hydroxide), PhosLock on the internet (http://www.marinedepot.com/PURA_PhosLock_GFO_Phosphate_Removal_Media_Phosphate_Remover_Chemical_Filter_Media-Magnavore_(PURA)-MN3111-FIFMCHPR-vi.html ); but I haven’t seen any detailed studies on it. The movie on the site is interesting.


pKsp = -log Ksp = 26, or 10-26 = Ksp = [La+3] X [PO4-3] where [..] is concentration in moles/liter. See two attached articles.

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"Once on the sediment, Phoslock, and the lanthanum phosphate within it, remain as in inert mineral component of the sediment. The nature of the bond between lanthanum and phosphate is such that it will not be broken under a pH range wider than found in almost any natural lake (pH 4-11). Even more importantly, the bond will not be broken under anoxic (low redox potential) conditions, which are prevelant in most lake sediments and many overlying waters. Most other phosphorus binders, especially those containing iron, will release phosphate under anoxic conditions."

The fish you ate yesterday was raising in farm using this stuff. Seems better than GFO to me.

Many eco-toxicity tests have been undertaken on a wide range of test species by a variety of independent academic and government research institutions over the past ten years. Collectively, these reports demonstrate that Phoslock has a very low toxicity and is safe to use in naturally occurring environmental conditions at recommended dosages. A detailed overview of these studies (pdficon_small_10x10.jpg 800 Kb) has been produced by the Technical Department of Phoslock Water Solutions in Australia. In addition to this overview, several of the most important eco-toxicity assessments conducted by external agencies and institutions can also be downloaded from the Publications Page.

Furthermore, over the past four years, more than 100 Phoslock applications have been completed in over 20 countries with no evidence of toxicity having been observed in any of the species of aquatic flora and fauna that have been tested.

Edited by barderer
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Marine geochemistry is pretty complicated, and when you throw in livestock with a wide variety of specific needs, I would use an abundance of caution. The problem here is even just the lanthanum, that has been used with some success in reef keeping. The problem is the rate at which the phosphate is removed, the fact that it can precipitate out alkalinity, and any other unknown reactions that can affect reef inhabitants. I'm not saying this won't work, I'm saying extensively test it before putting it into use on a closed reef tank system.

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