something strange is happening in my tank,

[Beam]

Hi all,
my tank is now more than a year old, started with dry rock, and bacteria in bottles. it took some time to stabilize the parameters, but since several months, everything is ok, and i see more and more coraline growing on the pumps, the rock and the backwall. fish and inverts are doing great.

my ph is stable around 8.00 - 8.3 temp 78.5 - 79
alk at 9.3 dkh calcium at 440, mag at 1400 phosphate and nitrate all near zero.
it's a red sea reefer 350, i have 2 Wav for the water flow, + 1 reefwave and another pump, and i have 2 reef led 90 for lightning

but, something really strange is happening, i had some corals in my old tank, which was lighted in T5 and all my old corals are doing pretty bad in the new tank i had an acropora which was doing pretty good, but now, from time to time, a branch bleaches suddenly and dies. i tried to move it to another place, without success. i had a candy cane, same thing, it almost doesn't inflate anymore, i even have zoas that are not as beautiful as before.

what is strange is that i also bought some new corals, acan, pocilliopora, zoa, cheap one, just for testing my tank, and they are doing very well.

so why are my old corals dying and the new ones doing well? i just don't understand, any ideas ?

 

[vetteguy53081]

Did you acclimate them to new tank and start with low light?

 

[Beam]

yes i did acclimate them, like i always do , and i used the 30 days acclamation schedule on the reef beat app

I also watched both day and night to see if there were any parasites and I didn't see anything at all that could bother the corals, and anyway, how could it reach my old corals

 

[Timfish]

First thought is did you match the PAR levels for the old corals? 2nd is what was the PO4 and nitrate levels in your old system? A sudden drop or imbalance in nitrogen and phosphate can shift the mutualistic relationship bewteen corals and zooxantheallae to a parasitic one to the detriment to the corals.

Fig 1 from thsi paper:

Nutrient Availability and Metabolism Affect the Stability of Coral–Symbiodiniaceae Symbioses

Coral reefs rely upon the highly optimized coral–Symbiodiniaceae symbiosis, making them sensitive to environmental change and susceptible to anthropog…

www.sciencedirect.com

 

[Glenner’sreef]

T5s in the old tank, old corals doing great! Leds in new tank old corals not doing great. Your new coral are doing well and maybe came from a similar lighting setup. Maybe lighting change?

 

[Beam]

thank you, it makes a lot of sense, i will read the article carefully.

i am not able to know the nutrients in my old tank because it has been closed for more than a year. but it was probably higher than in my current tank. as it was running for around 10 years, also, i did not keep any of the live rock from my old tank, because there was too much green air algea, turf algea, aptaisia and other undesirable. so, even if i seeded some different strains of bacteria, pods, and dose some phyto, the biodiversity is probably much lower.

The PAR was probably a little lower, because I only had 4 T5 on a 50 gallon tank.

I plan to add corals in the next few months, and with that in mind, I will soon rent a par meeter and take measurements of my new tank. I will have a better idea then.

 

[Beam]

T5s in the old tank, old corals doing great! Leds in new tank old corals not doing great. Your new coral are doing well and maybe came from a similar lighting setup. Maybe lighting change?

that's what I'm inclined to believe too, maybe also the change of water chemistry, nutrients etc.