Coral dying

Carl C · Jun 6, 2021

my coral I’ve had for 2 plus years is suddenly experiencing necrosis or at least whitening
Hard to tell from pic ; literally was fine yesterday

my parameters are fine … calc 408, alc 10, nitrate 1.2 , phosphate 0

the changes recently are

1) I put my arm in the tank with sunscreen on (yesterday) i immediately noticed a oil slick in the water

2) I’ve had auto water change off for 3-4 weeks to try and get some nutrients going
Gonna turn it back on

thank you

Uncle99 · Jun 6, 2021

Phosphate of zero is not a good number, even nitrate is maybe low at 1.2ppm.....I’d dose that phosphate up to. .08ppm and nitrate to 5-10ppm, otherwise corals starve.

Carl C · Jun 6, 2021

Uncle99 said:
Phosphate of zero is not a good number, even nitrate is maybe low at 1.2ppm.....I’d dose that phosphate up to. .08ppm and nitrate to 5-10ppm, otherwise corals starve.

Super good point; however I’ve been 0/0
For over 2 years with this and all my corals; I’ve just learned about keeping nutrients up recently (still learning obviously) but literally this happened overnight ; I’ll dose phosphate now just in case
Thank you

Uncle99 · Jun 7, 2021

Yup, overnight, low nutrient would not kill.
But 0/0 for 2 years, wow, you must have extreme filtration.

I have always understood that low nutrient systems is a good thing, but, in my system, my corals reacted positively in terms of extension, colour and growth when provided an elevated and balanced amount.

Anything below 5ppm nitrate (Salifert) and lower than 0.08ppm phosphate (Hanna) is the point where my corals look hungry.

My nitrate is stable in the 5-10 mark.

I have to dose phosphate daily to maintain just under .1ppm, otherwise corals use it and it drops to 0.02ppm.

jeffchapok · Jun 7, 2021

The sunscreen would be my bet.

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ScottB · Jun 7, 2021

I am with @Uncle99 on nutrient deficiency. Your rock and sand naturally bind phosphates and release some into the water. But there can come a time where there is nothing left to release.

That said, some sunscreens are worse than others. There are many dive operators now that prohibit the application of sunscreen. These active ingredients seem to pop up on the "really bad for corals" lists. Very common in spray on formulations.