Raising Magnesium

[JayA]

My hammers (both of which are newer) seem to be regressing a bit in polyp size, although one of them for the first few weeks looked lovely.
My current tank parameters. 20 gallon tank with 8 and 1/2 hours of AI Prime 16 on approx 78% blues/uv/purple.
mild dinos (prorocentrum).
nitrate=50ppm (high, but stable... for months)
Ca=420
phosphate=0.25
pH=8.15
KH/Alkalinity=9.9
Mg=1260
SG=1.025

Should I try raising Magnesium? Will it be safe/right if I don't change anything else? I have only softies/LPS. Am I right to think this may be what is happening with the hammers? I have them in low-mod flow, and maybe mod light.

 

[PeterC99]

I find that my hammers do better with a little more flow. Have you tried moving them to new locations?

 

[JayA]

I find that my hammers do better with a little more flow. Have you tried moving them to new locations?

I have not moved them yet. I did try redirecting the flow onto them but they seemed to shrink even more? Maybe I just did not give them long enough...

 

[PeterC99]

Seems like you haven’t found the right spot yet.

 

[JayA]

Seems like you haven’t found the right spot yet.

How long do you observe them before moving or changing things again?