Sps dying from the bottom ????

[malira]

For about 2 to 3 months the sps have been slowly dying from the bottom up. It takes about 3 to 4 weeks but it final takes the whole frag. At first I thought it was only the frags on the racks but now it's begun on the rocks too.

Alk - 9 to 9.5
Cal. - 420
Mag @ 1300
No3 - 2 to 5

 

[sinekal]

How stable is your alkalinity. You say it tests 9-9.5, does that mean it swings between the two readings, and if so how quickly.

Unstable alk can absolutely causere tissue recession like you are seeing, and a variance from 9-9.5 over a short period is enough to cause it

 

[malira]

How stable is your alkalinity. You say it tests 9-9.5, does that mean it swings between the two readings, and if so how quickly.

Unstable alk can absolutely causere tissue recession like you are seeing, and a variance from 9-9.5 over a short period is enough to cause it

Since the coral have started dying my alk, calcium consumption has decreased so the alk has steadily started to rise but the swing isn't but 2 to 3 ppm per day

 

[SamsReef]

here are some common reasons for base up STN:
Water chemistry - two common ones are alkalinity swings and high phosphate. CHECK these two with reliable means(salifert and Hanna is what I trust)
Pest - aefw and red bugs are two common sps pests that you should look for...

Other than these just rule out common gotchas - salinity swings, temp, ammonia and stray current.

Sam