Phosphate Reduction - Intentional "Binder Rocks" in Sump?

[GotCrabs]

Question:
Does the idea below make any sense?

Idea:

• Calcium Carbonate based "rock" left in sump. Phosphates bind to the rock.
• Remove rocks from sump. Assume some easy handle around/through rock. Or maybe a basket of scraps.
• Soak over night in liquid X to remove phosphates on surface. (Please tell me what X should be. Preferably "home chemistry" type material.)
  • Ideally just a dip, rinse and back in the sump...but maybe an overnight soak.
  • Ideally I reuse the X material. Leave it in a tub with a lid.
• Put rocks back in sump for Y time. (Estimate how often I'd need to do this assuming it's a phosphate maintenance tool, not a major phosphate removal tool.)

Assumptions:

• "Rocks" could be some other high surface area material.
• Assume Phosphates are typically "low ish".
• Assume pH 8.4 as I've read this is the ideal pH for phosphate binding to Calcium Carbonate.
• 150g system

Does this make any sense? Would it be effective? Estimates on how effective?

Proposed "rock" materials?

Proposed soak material X?

On the surface this sounds like the "rock" is GFO in a reactor. Same process...except the idea above is intended to be minimal cost and only just be "another rock" added to the system.

Feel free to tell me this is crazy. I'm just looking for alternatives to lanthanum chloride for the future.

 

[Saltyreef]

Sounds good in theory but it would likely be 100x less work to just add some gfo to the sump to soak up the po4.
And a lot quicker too.