Hi Saltgater,
Sorry to hear of your issues. If you can confirm that your PE issue is not due to a pest, then there are three issues IME that can/will cause a lack of PE.
1) low flow. If your flow is not sufficient to constantly move all of the polyps, then you can have issues with PE. The goal is to have flow strong enough to ensure polyp movement, but not strong enough to make the polyps look like they are in a wind tunnel. I have experience with stunted growth due to over powering laminar flow.
2) lighting. As a previous poster stated, you can place a coral in lower light to see if it will improve. I have a echinata in my tank that will show PE on lower shaded branches, but will not show PE on the brightly illuminated branches. At night, all polyps are extended.
3) starvation. A lack of nutrition (such as 0 phates and trates for an extended period of time) can cause lack of/no PE.
one additional possibility, but I doubt that it is impacting your PE
4) low potassium. As a ZEO user, I experienced this first hand. The ZEO media removes potassium along with ammonium. When my K+ levels were close to 320, I experienced slow to no growth and retracted PE. Of course my tank was being starved at the same time, so that also didn't help any.
Good luck with your issue.
James