I recommend using Phosphat-E Phosphate remover and dosing at half the recommended dose 2-3 times within a week span. It will allow slow lowering but nothing too abrupt. I recently went through this. I was at 0.3 and I brought it down to 0.5, there will be a slow creep but its at a healthy number.
Here is Larry's phosphate remover calculator for many different products:
Here is Larry's phosphate remover calculator for many different products: