Hi Jim;

The CuLater is as easy as it gets -- if it works.

The cal hypo method depends on simultaneously oxidizing the metals and precipitating calcium carbonate onto the filter to trap the metals. It will NOT work while you have functional levels of phosphonates in the water. It WILL make things go 'BOOM' if you have a feeder or something else that allows undissolved cal hypo to contact almost any other pool chemical.

One more point to consider: if you do have an input source of metals, the phosphonates will eventually fail. If you don't have an input source -- you may have ALREADY removed the metals, and don't actually need the phosphonates any longer.