Why is this happening?

Goniapora is swelling up , it seems normal on one side but occasionally it swells up. I have never seen this before and I can't find any info about it. It goes up and down a little today. In a matter of minutes it swells up and the polyps don't move in the water flow or the become almost swallowed up by the swelling, then a few minutes later it gouges back down. I did a 5 gallon water change today. All the water parameters seem good. I did change power heads yesterday because the original ones were wore out and sometimes would not come on when the wave maker commanded them to. I got some 1200 series that are stronger flow then the original JBJ heads. Here is a picture.

If you look closely the left side front of the coral is the part that is swollen in the photo but the right side looks more normal.help!!

Wish I could help. I know very little about their behavior.

I have been told that the coral is probably cleaning itself out or feeding. I was also told it could be I had to much flow from new power heads . I have adjusted them to not be to strong against this coral and it's not puffed up anymore. It seems to be fine again. It may be that it is doing what it is supposed to do and it's normal.

Mine does the same thing, in a couple of days, once it's use to the flow, it should start extending it's polyps again. Scared me the first time too. Have you spot fed it or used reef snow in the tank?

Anthony I have tried to spot feed it some food called Roti feast, and tried some phytoplankton as well. I bought some more powerful return pumps after I found the stock ones not turning on when my wave maker would start them up sometimes. The flow seemed to be to much no matter how I adjusted the direction of the outflow . Itook the return pumps back and bought some MJ 900 and the flow looks better. But now the goniopora does not come out fully now. It's not puffing up anymore but it won't come out all the way. I'm hoping that it just may be adjusting to the changes I have made with the flow. I did a salinity check with m refractometer, it is 1.026. Calcium is 450, magnesium is around 1380 to 1400. The temp is fairly steady at 78.5. The rest of the tests are good.

The first ones I bought were MJ 1200 pumps and they are the ones I took back because of to strong a flow.

Oh yeah I have tried cyclops food as well.

A) Reduce your flow or redirect it.
B) Too much or too little lighting.

Often if you see part of it retracted, it's because something stressed it to retract. In this case you said you had too much flow.