I'm pretty sure that the brightwell aquatics liquid phosphate remover is Lanthanum chloride based. Just like the Seaklear pool phosphate remover some reefers use. From what i have read so far. It works very well but you have to be carefull not to over dose or you'll get some precipitates in your tank and it might be harmfull to your fish. Also, most use it with some kind of filter to take out the precipitate. A good way to dose it is to dose in the overflow and put a filter sock on return pipe to your sump. The filter sock should be of no more than 10 microns to catch the fine particules. Some use a Diatom filter too. And some add the dosage to the skimmer. Went you start dosing, start slow and adjust your dosage slowly.
I should be trying this with the seaklear Aquaria phosphate remover in a few weeks.
I will try it because i've got lots of phosphates leaching from my live rocks. When my phosphates are low enough, i'll switch back to gfo.
Keep us posted on how you do with it.
The one I'm talking about here is the white pellet kind that you'd run in a reactor like GFO. I've heard it might put some aluminum in your tank, but only some tanks will have a problem with it.