Phosphate in GAC
- Thread starter NormanB
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Bucs20fan
Valuable Member
Theres a hundred different kinds of GAC that all say they dont leach phosphates, they all will eventually if you dont change it with a proper maintenance procedure. Pick which kind you like, reactor or not, and change it accordingly.
NormanB
Well-Known Member
Thanks for your quick response.
I currently use Marineland Black Diamond, mixed with Phosguard in a reactor. 0.5 cup of Phosguard and 0.25 cup of Black Diamond. This is normally changed weekly or more often depending on phosphate level in the tank.
Just for Ha Ha's I've got 0.25 cup of Black Diamond in RODI water, will let it sit for 24 hours then test for phosphates.
I'll report back what I find.
Thanks again!
I currently use Marineland Black Diamond, mixed with Phosguard in a reactor. 0.5 cup of Phosguard and 0.25 cup of Black Diamond. This is normally changed weekly or more often depending on phosphate level in the tank.
Just for Ha Ha's I've got 0.25 cup of Black Diamond in RODI water, will let it sit for 24 hours then test for phosphates.
I'll report back what I find.
Thanks again!
Bucs20fan
Valuable Member
If you change your carbon weekly and dont have a phosphate level of like 3.0, you shouldnt have any leaching.
Bucs20fan
Valuable Member
I dont run carbon anymore, my preference has changed to chemipure elite. And I change that every 2 weeks.
NormanB
Well-Known Member
Thanks for your input.
After 24 hours of the GAC soaking the PO4 was 0.09 ppm. I'll maintain the water volume and check again after 7 days.
I picked 7 days as that is when I normally have to change the Phosguard.
After 24 hours of the GAC soaking the PO4 was 0.09 ppm. I'll maintain the water volume and check again after 7 days.
I picked 7 days as that is when I normally have to change the Phosguard.
homer1475
Figuring out the hobby one coral at a time.
Ummm.... chemipure elite, is just carbon and GFO. So you still do run carbon.
Bucs20fan
Valuable Member
Yes, I meant I dont run just plain carbon anymore, I should have specified.
Randy Holmes-Farley
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I’ve never seen any evidence that GAC has enough phosphate to worry about.
This has more:
reefs.com
From it:
The same sort of calculation applies to analyzing other phosphate issues, such as the GAC in scenario three. The issue of finding “high” phosphate in GAC soaked in fresh water was frequently quoted as a reason to use one or the other brand of GAC, and probably still is. But simple analysis as shown above for the food rinsing puts the lie to this being a big problem.
One needs to consider how much GAC one will really use in the aquarium and how often it is added in order to interpret how important the added phosphate is. A typical recommendation might be 1 cup of GAC per 100 gallons of aquarium water, and to change it in 4-6 weeks. Let’s assume we detect 0.5 ppm phosphate when a teaspoon is placed in a cup of water, and we get scared by the dark blue color during the test. Is this reasonable? That 0.5 ppm from a teaspoon in a cup of water translates to 0.015 ppm phosphate when a cup is used in 100 gallons.
That 0.015 ppm may be significant, being a typical target concentration level for reef aquaria and amounting to about half to a twentieth of the amount added daily in foods, but remember, it is used for 4-6 weeks. During those 4-6 weeks before the next replacement, foods add 50-700 times as much phosphate. So while it is not unreasonable to look for another brand of GAC, to blame phosphate or algae issues in the aquarium on its use would stretch credibility because it is a very tiny portion of the total phosphate being added.
This has more:
Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both
Foods are by far the most important source of phosphate in most aquariums. In considering whether sources of phosphate other than foods are important, one must carefully look to the actual amounts involved to determine whether other sources are even worth trying to minimize.
reefs.com
From it:
The same sort of calculation applies to analyzing other phosphate issues, such as the GAC in scenario three. The issue of finding “high” phosphate in GAC soaked in fresh water was frequently quoted as a reason to use one or the other brand of GAC, and probably still is. But simple analysis as shown above for the food rinsing puts the lie to this being a big problem.
One needs to consider how much GAC one will really use in the aquarium and how often it is added in order to interpret how important the added phosphate is. A typical recommendation might be 1 cup of GAC per 100 gallons of aquarium water, and to change it in 4-6 weeks. Let’s assume we detect 0.5 ppm phosphate when a teaspoon is placed in a cup of water, and we get scared by the dark blue color during the test. Is this reasonable? That 0.5 ppm from a teaspoon in a cup of water translates to 0.015 ppm phosphate when a cup is used in 100 gallons.
That 0.015 ppm may be significant, being a typical target concentration level for reef aquaria and amounting to about half to a twentieth of the amount added daily in foods, but remember, it is used for 4-6 weeks. During those 4-6 weeks before the next replacement, foods add 50-700 times as much phosphate. So while it is not unreasonable to look for another brand of GAC, to blame phosphate or algae issues in the aquarium on its use would stretch credibility because it is a very tiny portion of the total phosphate being added.
Goodersgold
Active Member
This article explained so much to me. I have been tackling high Phosphates for a good few months now, the best thing that has helped bring this down is reducing the pellet food. Even Rowaphos and Lanthanum Chloride used alone has little impact IMO.
Randy Holmes-Farley
Reef Chemist
Staff member
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Excellence Award
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You're welcome, folks.
Happy Reefing!
Happy Reefing!
