SPS Tips Dying!!

[Whitebird1]

New frag Tank
Plumed in a loop into the main system= same water
Same lights, T-5, 2x 6500K 1xfiji pink 1x antinic but the frag tank is more shallow.
perhaps more current, water movement.
The tips of pink birds nest and a few green birds nest in the frag tank are dying at the very tips and growing black sh#t and green on them. None of the same in 2 other tanks in the system are doing this! Any Ideas???? Greg

 

[dun2run]

bump

I have an acro frag that has a black "mold" looking spot on it too. Been wondering what that is. Anybody seen this stuff before?

 

[Whitebird1]

Some of the guys stopped by and the idea was alk swings causing the tips to burn. I balanced the Alk and Cal and upped the Mag to help stabilize the Alk, it seems to have worked. I cut off the damaged tips and the are healing now with no further problems.
Here a calculator that is a big help.
http://reef.diesyst.com/chemcalc/chemcalc.html
Hope this helps.
Greg

 

[mike_cmu04]

I would also guess alk burn like said above get your parmaeters stabile and cut off the dead tips and it should start growing again.