If you really think water chemistry is the issue, I think escalating water changes is a good idea. Agree with the guys above.
Is it possible they are getting TOO much flow? I only have a few hammers in my tank but they are only happy in pretty low flow, and the amount of flow pretty much correlates inversely to their polyp extension.
Thanks everyone for all if the feedback it's been helpful with making me consider more possibilites.
I haven't yet fully manipulated flow to all extremes. yet i started the hammers higher up with more flow than I put them down just above then crushed coral substrate with lower flow.
The mp40 I had on the tank since i started it. I started with 40% max output. Than 3 weeks ago I brought it down too 25% max output.
I originally only had the mp40 and s1 vortec return line, mounted on the right side of the tank both blowing right to left. The flow seemed enough to cause a slight back and forth motion of the coral.
2 weeks ago I was able to get a 2nd mp10 running and put it in my main tank across from the other mp10. That allowed me to take the hygger out and put it on the left side of this tank.
None of those changes: moving coral, lowering mp 40 output, or adding the hygger made any noticeable difference in the hammer's extension.
*I just lowerd the mp40 down to 10% to see if it makes a difference.
This is less flow than the mp10 and hygger had in my 32biocube where the hammers originally were. If you think I need go lower than 10% should I probably just try turning the mp40 off?
**I will probably have to buy 15 gallons of ro from Neptunes in order to try a 15 gallon water change. By the numbers that should be 20%. In truth it may even be closer to 30%. If factoring in the volume taken up by rock, substrate, sump biobmedia, and equipment inside the water.