Very old Ducan now opening only half? Why?

[daniel_mourra]

Ive had this duncan for about 2 years now. Its always been opening up great and always in the same tank spot. But about 3-4 weeks ago, only half of it opens as usual, the other half refuses to open. Any idea why only half my coral is opening? I have never moved it. NO changes to light or flow in the last 12 months…. NO NEW FISH OR INVERTEBRATES in the last 8-10 months.

Water parameters are:

Salinity 1.022 three weeks ago; brought it up to 1.025 in 3 weeks. Now 1.024.

Dkh: 8.4-8.5 very very steady.

Ca: 420-440 steady.

Mg: 1500 (went up due to bringing salinity up. Now in the process of going down. Now at 1480).

Nitrates: 5ppm very very very steady.

Phosphate: 0.15 steady.

Temp: 25.5 C (78F)

Par: 120-180 in that spot. Its always thrive in there.

 

[mcarroll]

Salinity 1.022 three weeks ago; brought it up to 1.025 in 3 weeks. Now 1.024.

Off the top I'd have to say this at least relates to the cause....was the salinity drop a mystery or do you know what happened?

Its always thrive in there.

It looks like the downstream side of the coral is what's closed...maybe consider a flow rearrange or maybe even adding a pump?

 

[daniel_mourra]

Off the top I'd have to say this at least relates to the cause....was the salinity drop a mystery or do you know what happened?


It looks like the downstream side of the coral is what's closed...maybe consider a flow rearrange or maybe even adding a pump?

Yes i know the cause. I use chris meckleys kalkwasser method which adds alot of kalkwasser (more than evap) so it drops salinity if i am not vigilant. Every week it goes from 1.026 to 1.025 in 7 days and then i do a water change and bring it back up to 1.026 as i change with new “saltier water”.

 

[Piotrek]

Not 100% sure, but might be flow or light related due to coral growing. Maybe the closed side isn't getting enough light anymore due to the other side covering it?

 

[Jimbo327]

How often do you do water change? And how much water do you change?