Calcium carbonate phosphate removal

[Cory]

I want tk remove po4 with calcium carbonate but was wondering if i could use limewater as the calcium?

My idea is to bubble it until all the calcium hydroxide is converted to calcium carbonate then filter the sand out, rinse it and dose the sand to see what effect it has on po4. Feasible?

 

[Garf]

Years ago folks said that just adding Kalk to the tank would bind up a certain amount of phos theoretically. Don’t know if it was ever proved though.

 

[Cory]

I put a cup of calcium hydroxide into 3 gallons of ro water. And i have an air stone bubbling into it. Conductivity is 9.3 ms/ C, what Conductivity would indicate all of it was converted to calcium carbonate?

 

[Randy Holmes-Farley Verified Community Expert]

I want tk remove po4 with calcium carbonate but was wondering if i could use limewater as the calcium?

My idea is to bubble it until all the calcium hydroxide is converted to calcium carbonate then filter the sand out, rinse it and dose the sand to see what effect it has on po4. Feasible?

Yes, but it seems like a lot of work to make powdered calcium carbonate.

 

[Randy Holmes-Farley Verified Community Expert]

I put a cup of calcium hydroxide into 3 gallons of ro water. And i have an air stone bubbling into it. Conductivity is 9.3 ms/ C, what Conductivity would indicate all of it was converted to calcium carbonate?

All converted?
0 mS/cm lol

 

[Dan_P]

I want tk remove po4 with calcium carbonate but was wondering if i could use limewater as the calcium?

My idea is to bubble it until all the calcium hydroxide is converted to calcium carbonate then filter the sand out, rinse it and dose the sand to see what effect it has on po4. Feasible?

If you are interested in using calcium carbonate to bind PO4, pass aquarium water through wash aragonite sand.

 

[Cory]

Yes, but it seems like a lot of work to make powdered calcium carbonate.

The purpose is using phosphate free calcium carbonate. This way it would work better no?

 

[Cory]

All converted?
0 mS/cm lol

But to measure that id need to have clear settled calcium carbonate water? Suspended calcium carbonate would effect conductivity?

 

[Cory]

If you are interested in using calcium carbonate to bind PO4, pass aquarium water through wash aragonite sand.

I have a 40lb bag of oolite aragonite. My concern is it might be saturated in po4 already.

 

[Dan_P]

I have a 40lb bag of oolite aragonite. My concern is it might be saturated in po4 already.

Test your hypothesis. Soak a sample of the aragonite sand in freshly made salt water, measuring the initial PO4 and then PO4 after a week.

 

[Randy Holmes-Farley Verified Community Expert]

But to measure that id need to have clear settled calcium carbonate water? Suspended calcium carbonate would effect conductivity?

Not really. Suspended particles aren't a big deal. Maybe they push the value down a tiny bit.

 

[Randy Holmes-Farley Verified Community Expert]

The purpose is using phosphate free calcium carbonate. This way it would work better no?

I don't know.

 

[Cory]

Fwiw my home made limewater calcium carbonate didn't reduce po4 at all. But adding some new dry rocks made from dead coral skeletons clearly did by about .20ppm.

 

[Randy Holmes-Farley Verified Community Expert]

Fwiw my home made limewater calcium carbonate didn't reduce po4 at all. But adding some new dry rocks made from dead coral skeletons clearly did by about .20ppm.

Thanks for the update.

 

[Garf]

Though not exactly was this thread was about, Did anyone get any further with this? (Adding clean aragonite into a filter), I imagine as long as the source of sand was clean, it could bind lots of phos. On my recent tank I had no sand but non porous dry rock and it took months to see any phosphate, even with a bit of TSP dosing and F/2 fertilizer. Them days are behind me now, so now would want to try and reduce phos, lol. Normal service has resumed
Failing any testing, I will just throw some in a mesh bag and see what happens. I never got on with GFO, not sure about Lanthanum and am not doing an algae scrubber again. TIA

 

[Garf]

For what it’s worth, I’ve been putting 3 massive spoons of a certain sand in a mesh bag in my sump, each week (3 weeks so far). It clouds the water for an hour (I do this while the filter sock is dirty) to maximize fine particulate filtration. The phos level in my tank has reduced (salifert), weekly 10% waterchange, barebottom tank.

 

[Randy Holmes-Farley Verified Community Expert]

For what it’s worth, I’ve been putting 3 massive spoons of a certain sand in a mesh bag in my sump, each week (3 weeks so far). It clouds the water for an hour (I do this while the filter sock is dirty) to maximize fine particulate filtration. The phos level in my tank has reduced (salifert), weekly 10% waterchange, barebottom tank.

It's an inexpensive version of the "coral snow".

 

[Garf]

It's an inexpensive version of the "coral snow".

Yep, and the water is crystal clear afterwards.

 

[Midrats]

Why not just throw in a couple of scoops of calcium carbonate powder?

 

[Garf]

Why not just throw in a couple of scoops of calcium carbonate powder?

Haven’t got any of that. I do have a 20kg bag of sand, lol.

Edit - my initial assumption was that the phos would bind to the sand in the bag, perhaps it is, maybe it’s not, dunno.

Edit 2 - however, I do have a mortar and pestle