Trying to figure out what killed my SPS corals:2 much light or high Ca and Alk levels

gavij012379

New member
I moved live rocks and corals from my 60 gallons into this 180-gallon tank and been running it since end of March this year. The SPS frags I had were doing great except some of the corals (zoas and sps) were bleaching most probably because I was trying to run two Kessil AP700 over a 6 feet tank at 90% and 10" off water surface. I would constantly run it at acclimation mode for 14 days (can't go more than that) and try different settings. I lost some corals mostly zoas but most were doing okay.
I started adding more SPS around end of April and more in June and they were doing fine as well. Around June I decided to maintain my Calcium at 470 ppm and Alkalinity at 12 dKH per Red Sea SPS accelerated growth value. My alkalinity and calcium were probably already there since I was dosing but in hindsight the old test kit I was using was giving me a lower reading of like Ca 410 ppm and Alk 10.1 dKH. When I bought a new test kit, I doubt the result I was getting since my Mg was like 1600 ppm without dosing for it (looks like Red sea coral pro and liveaquaria salt are pretty high in Mg and Bi-ionic 2-part soln I was using had Mg as well). So, I started dosing more and my Ca was probably at around 520 and Alk at 11.5 dKH around the end of August when I saw one of my very old SPS starting to bleach in an unusual way and also in areas where it gets less light. I was out on vacation for the next 5 days and didn't dose the tank (Ca and alk level decreased as expected) and when I came back on 8/31, I noticed the same thing in a lot of the SPS. Basically, I saw that there was decreasing polyp extension, coral color looked fading and after a while the tissue will be gone and the coral white and get covered in algae soon after. It took around 7 -10 days for the process. Now in a little over 2 months I have lost around 40 sps, mostly frags but still around 1200 bucks. Most of the LPS were doing fine but I lost some towards the end as well.
In the beginning I thought it was the light that caused the corals to die even though I had dialed it down to 65% from 90% before. But now I think it is the high Ca and Alk level that killed the corals. I am sure the light was bothering them as well. I am just trying to see if anyone has experience something similar or has an opinion since I don't want to spend another 1200 just to lose it in a few months. Lately it feels like too much hassle to keep these things alive.
 

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Timfish

Timfish
Premium Member
What are your other water parameters? Particularly phosphate, phosphate deficiency in corals will make them very sensitive to the changes you've made with lighting. In the future I would strongly recommend getting a PAR meter to see what your corals are actually getting. Here's some links on phosphate and corals:

https://www.cambridge.org/core/jour...reef-corals/AFB1CF4CB68823BD13AD254623FD3C7C#
An Experimental Mesocosm for Longterm Studies of Reef Corals

Phosphate Deficiency:
Nutrient enrichment can increase the susceptibility of reef corals to bleaching:
https://www.nature.com/articles/nclimate1661

Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:
https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full

Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
https://www.sciencedirect.com/science/article/pii/S0025326X17301601?via=ihub

Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach
https://www.sciencedirect.com/science/article/pii/S0022098111004588

High phosphate uptake requirements of the scleractinian coral Stylophora pistillata
http://jeb.biologists.org/content/214/16/2749.full

Phosphorus metabolism of reef organisms with algal symbionts
https://esajournals.onlinelibrary.w...98e60zfBEvx5IcIVGhmlpUYmzIJuqUNVm0sG8_0vth6lq
 

Oldreeferman

New member
Sorry to hear of so much live stock losses, that just blows and i experienced that once myself tho at a much lower lvl of loss.
I learned after the fact that it was caused by parameter swings that i was not monitoring like ALK, MAG, and CAL as well as PH close enough. It was mainly caused by Alk issues mostly and once i got everything balanced all the corals were healthy again with NSW params holding steady.
Too high above normal sea water or too low then quickly re-adjusting back to normal lvls is a ticking bomb with acropora as they demand pristine water conditions all the time & the big word STABILITY. Even easier to keep SPS corals demand it but unlike the acroporas they usually just stop extension & stop growing and go into a safety mode but recover if the issue is caught & fixed, good examples are Pavona, lepos, passamacoras, etc.. but they are hardier & usually will recover. Lowering the lighting is a good move start low & up the lighting after watching how the acros look, lighting shock is worse then too low a light on them. Now that the lights are turned down id focus on precise stability maintained just a tad above new sea water lvls if you can get that spot on & stable i will bet everything will start to be happy just don't do any fast adjustments better to change things slowly then too fast as any fast changes also cause shock on delicate acros. I also had the bad exp of the algae starting to grow on the dead parts of my corals again it was due to params out of whack, in the end i eventually had to cut away the offending algae from my corals & do some re-fragging to rid my DT of it , I also now dose NOPOX that lowers Nitrates & phosphates to a lvl sustainable for all SPS & acros. im at .2 on nitrates & almost no Phosphates to measure. Great stuff if these are of any issue i highly recommend it. Good luck and be patient takes time for corals to recover but they will if its just params issues & its resolved. Took me 6 months to get back to a normal clean tank once i focused on keeping the tank stable.
 

gavij012379

New member
Thanks for your feedback guys. I did large water changes to bring the Ca and Alk level down. Now it's just waiting to add corals until I can maintain the levels.
 

nhutwu

New member
I moved live rocks and corals from my 60 gallons into this 180-gallon tank and been running it since end of March this year. The SPS frags I had were doing great except some of the corals (zoas and sps) were bleaching most probably because I was trying to run two Kessil AP700 over a 6 feet tank at 90% and 10" off water surface. I would constantly run it at acclimation mode for 14 days (can't go more than that) and try different settings. I lost some corals mostly zoas but most were doing okay.
I started adding more SPS around end of April and more in June and they were doing fine as well. Around June I decided to maintain my Calcium at 470 ppm and Alkalinity at 12 dKH per Red Sea SPS accelerated growth value. My alkalinity and calcium were probably already there since I was dosing but in hindsight the old test kit I was using was giving me a lower reading of like Ca 410 ppm and Alk 10.1 dKH. When I bought a new test kit, I doubt the result I was getting since my Mg was like 1600 ppm without dosing for it (looks like Red sea coral pro and liveaquaria salt are pretty high in Mg and Bi-ionic 2-part soln I was using had Mg as well). So, I started dosing more and my Ca was probably at around 520 and Alk at 11.5 dKH around the end of August when I saw one of my very old SPS starting to bleach in an unusual way and also in areas where it gets less light. I was out on vacation for the next 5 days and didn't dose the tank (Ca and alk level decreased as expected) and when I came back on 8/31, I noticed the same thing in a lot of the SPS. Basically, I saw that there was decreasing polyp extension, coral color looked fading and after a while the tissue will be gone and the coral white and get covered in algae soon after. It took around 7 -10 days for the process. Now in a little over 2 months I have lost around 40 sps, mostly frags but still around 1200 bucks. Most of the LPS were doing fine but I lost some towards the end as well.
In the beginning I thought it was the light that caused the corals to die even though I had dialed it down to 65% from 90% before. But now I think it is the high Ca and Alk level that killed the corals. I am sure the light was bothering them as well. I am just trying to see if anyone has experience something similar or has an opinion since I don't want to spend another 1200 just to lose it in a few months. Lately it feels like too much hassle to keep these things alive.
I never keep alkalinity that high my always at 8.0-9.0
 
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