Acropora dying, out of nowhere, and quickly. What is going on?

[mhart032]

I think the ICP will be a big help. 

[+BobcatReefer]

Really?  Not sure these guys have ever been considered helpful:

 

 

....I'll see myself out...

 

[eddius-maximus]

ICP results arrived. Everything green except this. 1.2 mg/l phosphate. And this is after quite a substantial amount of water changes. 

I’ve been testing po4 with a Hanna and never got a single reading over 0.03. Bad reagent. 

Im thinking maybe my new rock on the right has been leeching phosphate. I’ve never in my life seen phosphate this high before and I am assuming it could cause some death. 

[victoly]

Before you do anything drastic, get some new reagent and recheck with your hanna. Its possible that the lab test was off and yours was right....

[eddius-maximus]

Same page. I ordered a Salifert test. 1.2ppm. Went back to my old Hanna. 0.015 ppm. 

[victoly]

huh. weird. was the reagent expired? Glass on the cuvette chewed up? junk on the photometer sensor?

[jolt]

Eddius if you want to swing by and do a test with my hanna low range I am around today and tomorrow

[eddius-maximus]

I appreciate it! I actually have two new po4 kits here. Both read 1.2. I’m slowly bringing it down now. 

Would phosphate reading that high cause rtn in acros? 

[jolt]

I have no idea on what happens with phosphate that high

[mhart032]

I believe it would. I believe there is a fine line between what they love and hate. We all know sps is very finicky, there kind of like a naso Tang you look at it sidways and it gets sick. It's very possible it bleached losing all the  zooxanthellae and not actually rtned at first just gave the appearance. 

We also don't really know how quickly the rise was in the p04 either. (Spell check sucks) 

[+Dogfish]

http://www.reefkeeping.com/issues/2006-09/rhf/

[Timfish]

On 5/26/2019 at 1:54 PM, eddius-maximus said:

I appreciate it! I actually have two new po4 kits here. Both read 1.2. I’m slowly bringing it down now. 

Would phosphate reading that high cause rtn in acros? 

No,  watch Richard Ross' video   At 5 mg/l your nitrate I think equals 80 µmol.   This is double the levels found to have a negative impact on skeletal growth in this paper.  This problem appears to be corrected in part by increasing DIC, alklinity, which you are keeping at 8.5 dKH.   My questions would be is that high enough for the nitrate levels you've been keeping.   What happens if there's a drop for a short period of time or fluctuations in the alkalinity?  What are the long term ramifications, it takes years for a coral colony to mature so how does keeping high nitrates affect it long term?  Much like the research done by SOuthampton university showing we need to keep PO4 levels higher than what's found in nature to prevent PO4 deficiencies that make our corals very sensitive to changes when we start messing with nitrates what do we have to do to compensate and what happens if there's changes in the organic forms of nitrogen we can't test for which corals will use (and prefer) instead of nitrates?

 

One of the scary things about the research I've read on coral disease is often the pathogens are found on healthy corals, the corals are already infected.  WHat kills the corals is stressors in the environment that reduce or alters the corals mucus production and/or associated beneficial microbes which provide protection.  In the paper above the negative effect high nitrates had on skeletal growth was caused by a reduction in the photosynthates released by the zooxantheallae to the coral.   Since these photosynthates are responsible for a significant portion of a corals mucus production and teh mucus chemical composition is dynamic and a harbor for beneficial microbes how is it affected when zooxantheallae reduce it's availability because of high nitrates?