Acro bleaching

[msantama]

Hello
I have this acropora in my tank about 2 month
It appeared a white spot since 2 week ago

The tank is 75gallons
biopellets (since 1 april)

D: 1023
KH: 9
Ca: 400
NO3: 10
PO4: 0,045
Mg: 1200

Light: 2 150W HQI and 4 T5 54W

I add 3 times a weeks zooplacton and phytoplacton Brightwell
I add 6 drop of Koralcolor brightwell once a week




Anyone can help me???

 

[MHG]

Biopellets and your nitrates are 10? I would try another test kit. The parameters look fine. Photos don't show much. Any changes in lighting? Is it bleaching or STN?

 

[jcarbone61]

What are you doing for a protien skimmer ? Even nitrates of 10 ppm are way to high , has there been any polyp extention ?

 

[shih87]

How old this tank is? Are these parameter steady enough? especial KH?

Hope you figure it out soon. Good luck.

 

[msantama]

Hello

I´ll buy another NO3 test kit to confirm this parameter.

Probably the problem is STN.

I changed the lights in January

The Kh is stable, I ckeck it in the evenings.

My protein skimmer is an Vertex Alpha 170. I clean the cup once a week.

The polyp extension of acroporas is not full.

The reef tank is 4 years old

 

[MHG]

Well if its stn, its likely an alk issue so confirming your alk is the way I would go... With nitrates in the detectable range you would be fine with higher alk. but if the alk is low you will get stn... I found several kits on the market measure the alk way higher than it is. IMO RedSea Pro and Hanna are the best. The elos is OK but there is some interpretation on the color shift if you are one of the unlucky folks who get green when you are looking for yellow...