View Full Version : Aluminum phosphate removers

Big E
07-07-2005, 04:26 AM
I'd like to add a small reactor to reduce the phosphate output of my calcium reactor.

I read comments recently that the aluminum based removers won't leach any aluminum at the lower effluent ph produced by a calcium reactor. Is this true? If so, at approx. what ph level would this leaching occur?

Thanks, Ed

07-07-2005, 11:28 PM
my understanding about the phosphate buffers is that the old-school aluminum type have a tendancy to leach phosphate back into the water, though I think they are quicker at reducing levels. They become saturated quicker however, and thus must be changed much more frequently. The new iron based products (Rowaphos and Phosban) have a more prolonged action and are a bit more safe and "sturdy" if that makes any sense. They also are less likely to leach phosphates back and don't have the posibility of leaching any aluminum into the tank.


07-10-2005, 11:16 AM
Ed where did you see that alluminium doesnt leach into the tank?? From what I read it does and has a direct toxic effect on corals and other organisms.


07-10-2005, 02:21 PM
It is the Al we are worried about that does the leaching. Also, if you are one of those guys that says, " hey lets put in extra" you may be in big trouble, as it may suck the alk out of the water and crash the pH. Once phosphate gets down to low levels activated alumina, which this stuff is, feeds on alk. We had a large thread on it on our chem forum. The director of SeaChem was there and he lost the agrument, as Randy posted data and SeaChem said they may have to rethink things. Even the presence of this stuff in the water has some bad effects on some corals.

Big E
07-11-2005, 04:04 AM

I've read this on a few recent threads about the subject from reefers. Most notably users of the Bio phos 3 (Al based) that some zeo reefers are using after their reactors to reduce phosphate.

I'll post a thread on the zeo forum & ask them to offer some info here. I'm not sure where the original thought of this low ph-no leach idea came from.

Thanks for the info Boomer

07-11-2005, 10:52 AM
Yea from My understanding the AL does leach and even worse the small particles that come from it make it even worse. I would look more towards a iron base product such as Rowa or simular.


07-11-2005, 04:28 PM
.We had a large thread on it on our chem forum. The director of SeaChem was there and he lost the agrument, as Randy posted data and SeaChem said they may have to rethink things.


Dou you have the link ? I was trying to look for it but I couldn't find it.


07-11-2005, 06:45 PM
I have a question along these lines....will activated carbon absorb aluminium? I know it absorbs copper, I was wondering if the same would be true for Al.....


07-11-2005, 07:49 PM
Fatboy this was one of them


Others on the NG RAMR, look for Criag Bingman and Leo Morin a few years ago


Let me go throguh my ga-zillion links. I have one on what GAC removes :D

07-11-2005, 07:56 PM
it is not there....still lookinfor more


.........not one hit on aluminium absorption by activated carbon. Particles need to be hydropohobic and Al + has not such proeprties would be the key

07-11-2005, 10:17 PM
hmmmm...I'm going to take that as a "probably not"? :D


07-20-2005, 12:11 AM
Along the same lines....what do you think?

Use of Steel Slag to Remove Soluble Phosphorus from Closed Marine Systems

Serge Parent1, Jean Bouvrette1, Rachel Léger1, Yves Comeau2
1Biodôme de Montréal, Montréal, CANADA H1V 1B3
2École Polytechnique de Montréal, Montréal, CANADA H3C 3A7

The accumulation of soluble phosphorus is a major problem in closed marine systems as it favors excessive algae growth, requiring constant efforts to maintain water quality. Experiments recently showed that steel slag produced in electric arc furnaces (EAF) retained up to 6 g P/kg slag in bench scale tests and efficiently removed phosphorus from the effluent of a freshwater fish farm. Our goal was to determine whether EAF slag could also be used to remove soluble phosphorus from a large marine aquarium. The study was conducted in a 3,000 m³ marine system at the Montreal Biodome. The system contained 20 mg P/L of orthophosphate (60 kg P). A 10 m³ pilot unit was built and filled with 9,500 kg of slag gravel 2-5 mm in size. Water was gravity fed into the unit and flowed through it in upflow mode at rates between 3 and 9 L/min. The unit removed 7 kg P (0.75 g P/kg slag) during its first two months of operation. Maximum daily removal was 165 g P/d at a flow rate of 9 L/min. Slag cementation and channelling were observed 30 days after startup. Operation of the unit had little impact on aquarium alkalinity and no adverse effect on fishes and invertebrates. Given a net annual input of 4 kg P, complete removal of soluble phosphorus from the system would take two years using four slag batches. The use of steel slag offers a promising solution to reduce soluble phosphorus accumulation in closed marine systems.

07-20-2005, 12:21 AM
Here is an assay of steel slag what do you think :D



07-20-2005, 12:42 AM
Thanks for the links Boomer...

Basically a big wad of impurities from the steel refinement process, I'd say it's likely got too many different potentially detrimental things in it and too inconsistant to be any kind of feasible long term phosphate removal media...

(unrelated side note, I work for the state DOT in highway construction, I know they commonly use blast furnace slag as an ingredient in Portland Cement...a common ingredient in artifical live rock...hmmm...yet another reason to avoid "aragocrete" IMO... :lol: )