SPS need some help/input

[Dr. Reef]

Guys i have 2 yrs old setup. its a 300gal total with 250gal tank + 65gal sump.
I have bermuda pink aragonite substrate. 2" deep. I have 150lbs of dry rock in main tank and about 50 more in rubble in sump. i run a reef octopus recirculating skimmer rated for 300-400 gals. i also run reef octopus dual chamber cal reactor along with 2x brs carbon and 3x brs gfo reactors and almost 2 basket all size chaeto algae in sump/refuguim.
I run a steady paramters of:
temp: 79F
salinity: 1.024-1.026
ph: 8.2-8.3
ammonia 0
nitrite 0
nitrate 0
Cal 420-440
alk 7.5-8.3 dkh
mag 1260-1300
flow: 4800gph reeflo return that puts out 4x800gph sea swirls. closed loop run by 2600gph reeflo dart and 3600gph reeflo dart for manifold to run all equipment. so i have a total of 10400gph which is 43 times the volume.

I use red sea regular salt. i do 35 gal water change every week.
lights: i have 5 Sol blues at 50% for 8 hrs a day and then i switched to vega color that are set to 30% for same 8 hrs.
i have few frags of SPS acros that have been in my tank for several weeks to months that never showed any sign of stress or problem but suddenly they start bleaching white from base up.
not all SPS are doing this but just a few frags.
i am an advanced reefer been in hobby for over 15 yrs and i have my basics covered like test kits and results errors etc. or any common newbie mistakes. so i need input..
Thanks in advance
Mike

 

[Dr. Reef]

phos is 0.03-0.09 range.

 

[Smnparish]

Big difference between .03ppm phosphate and .09...you want less than .03 ppm, I learned the hard way that high (over .03) will slowly kill sps, killing faster the higher the phosphate is.

 

[sirreal63]

Mike, does it coincide with the change in lighting? While I don't think it is the issue, you did change spectrum in intensities the corals are not acclimated to. FWIW I do not think it is a PO4 problem or it would be more widespread.

 

[Dr. Reef]

Mike, does it coincide with the change in lighting? While I don't think it is the issue, you did change spectrum in intensities the corals are not acclimated to. FWIW I do not think it is a PO4 problem or it would be more widespread.

Jack
i was also leaning towards light fixture changes. sols at 50% may not have had same par as Vega 50%. and like u said if it was parameter related it would be more wide spread. i have several sps corals doing great and a few not.

 

[sirreal63]

I only pose the question because I see something similar in my own tank. I typically run two bulbs, a 150 watt Radium on M81 and a 10K either on M81 or a 175 watt electronic. The difference in Par isn't great but the spectrum is vastly different. When I rebooted the tank after a move, I went to the Ushio 10K on the 175 electronic, the par went from 47 to 61, based on Sanjay's testing but the peaks in spectrum changed. I raised the fixture, moved the SPS to the sand and still bleached like crazy. I raised the fixture to where it was at least 30" from the corals where is usually 20". That should have more than made up for the difference in Par, but not the change in spectrum.

I wonder if the same is happening for you? We know the Vega has a more robust spectrum than the Sol, and corals do react to changes in spectrum as well as par. Mine are just now recovering from the change so I wonder if it would be wise to lower the intensity on the Vega's extra spectrum and raise it slowly? I know we don't have any testing on the spectrum of the Vega but I am sure it is a lot different (read as better) than the Sol.

I don't even know if it makes a difference, but it may explain why so many people bleach corals with the addition of LED's, not from a massive change in overall Par, but a change in areas of spectrum that the corals are not acclimated to. Something to think about, and I hope they recover.

 

[Dr. Reef]

Jack it all makes sense. i reduced the intensities to 30% on vega but i think i need to goto like 5% on the added colors of vega and leave the white blue and royal blue (3 common in sol and vega) at 30% for now and increase colors over time gradually.
you are right par may or maynot be the same but spectrum definitely is not with all the added colors.