carbon and phosphates, and phosphate removal.

[Liz]

So I know poor quality carbon can release phosphates into the water, and only "High quality GAC (granular activated carbon, right?)" or whatever doesn't because it is processed differently, without arsenic.

Something like that.

Anyways, I've had algae blooms, and they do seem to go away when I remove the carbon, however I like to use carbon to polish up my water and clean it up since I use tap water, not RO water.

I have been using "aquarium pharmaceuticals activated filter carbon", which is a cheapy I think. On the back, it says it "will not elevate phosphate levels when used as directed". Which I guess means it can release phosphate... but only under certain circumstances? Is there any way I can prevent it from releasing phosphate, so I can use it up? What circumstances cause it to release phosphate? It was my understanding that carbon either does or doesn't release phosphates.

I also have "aqua pure" phosphate removal pads to put in my filter... do these work? How often should they be changed out?

 

[TwoTankAmin]

This comes from thekrib.com

Some people (especially those with reef aquaria) are concerned about phosphate leaching from activated carbons. As a rule, buy only carbons made by reputable aquarium supply companies which have been acid washed during manufacture to minimize ash content. Carbons low in ash also help reduce the chance of undesirable pH shifts. Low ash carbons typically have lower phosphate leaching levels too.

The phosphate in GAC stems from the fact that activated carbon is manufactured from coal, which was once living plant matter. All living matter is high in phosphates. The leaching of phosphate from GAC is known to be high initially and to decrease over time. This problem can be mitigated significantly by presoaking your activated carbon for a few weeks before use.

 

[Liz]

Okay, so I could soak it first.

but how could a brand of carbon only leech phosphates under certain conditions? It says it won't when used properly but it doesn't say to soak it.

and "I also have "aqua pure" phosphate removal pads to put in my filter... do these work? How often should they be changed out?"

 

[mysis]

I run carbon on my reef and phosphate = 0, i think a lot to do with it is the biological filter my DSB. If you are concerned about phosphates and you do infact have phosphates in the tank, you could run rowaphos or phosban through a cannister filter, or even buy a RO filter.

You can also grow macro algae for absorbing nutrients aswell, have you actually tested for phosphates in your water?

 

[gomrjoe]

I have had some bouts with phosphates myself over the years, I have used Phosban, it works fairly well. I have had mixed results with it.

For the past 18 months I have switched to Phosphate and Silicate magnet, from Marc Weiss Companies, Inc. it has worked very well! I am very happy with the results of this product. You just put it in a media bag, dump it in your sump and within 72 hours, your phosphates and silicates are undetectable. You can get it from Dr. Foster&Smith or any of the large online warehouses.

If you can't do a refugium, this stuff works well. UV Sterlizers will also help keep some algae under control, as well as parasites, but most people I don't think have them on their setups.

 

[Liz]

I run carbon on my reef and phosphate = 0, i think a lot to do with it is the biological filter my DSB. If you are concerned about phosphates and you do infact have phosphates in the tank, you could run rowaphos or phosban through a cannister filter, or even buy a RO filter.

You can also grow macro algae for absorbing nutrients aswell, have you actually tested for phosphates in your water?

No, I haven't tested for them. I was just assuming, since it seems when I take the carbon out a lot of the nuisance algae clears up. I would like to actually test to make sure, though, before making an investment in higher quality carbon and/or more effective phosphate removal.

 

[mogurnda]

If you are worried about phosphate, it's probably worth testing for it. Both the tank and the carbon. Sprung and Delbeek recommend running a PO4 test on RO water, then adding some of your carbon to see what leaches out.

The Krib article is not quite right. There may be some PO4 from the organic material, but most of the phosphate in cheap carbon is there because it is treated with phosphoric acid to increase its porosity.