What’s wrong with my coral

[Bradsreeftank21]

Please help to identify what my coral is doing, it was growing rapidly and super happy and then today I see this weird spot where the polyps arnt our?

 

[WIReefer]

Could you tell us a little more about your tank how long has it been running, parameters?

 

[Bradsreeftank21]

It’s been running for 4 months now
Here is a pic of recent parameters

 

[WIReefer]

It’s been running for 4 months now
Here is a pic of recent parameters

What are your no3 and PO4? Maybe try dropping that temp down.

 

[Bradsreeftank21]

What are your no3 and PO4? Maybe try dropping that temp down.

My nitrates are 15 and I don’t have anything to test for PO4. I can try to lower temp I added him in the tank when my tank was only about a month old and he was massive and doing great and nothing changed parameters wise other than my nitrates went from 40 down to 15.

 

[WIReefer]

My nitrates are 15 and I don’t have anything to test for PO4. I can try to lower temp I added him in the tank when my tank was only about a month old and he was massive and doing great and nothing changed parameters wise other than my nitrates went from 40 down to 15.

I would invest in a nice phosphate test kit. What kind of coral is it?