Corals dying - Any Ideas?

[DC_40gallon]

I have had an Acropora die and a healthy birdsnest that was erupting in growth suddenly go south and slowly dying. I do a WC weekly at 5 gallons for a 40 breeder tank, 0 nitrates, 1400 magnesium, 480 calcium, 9-10 dkh alkalinity, salinity 1.026 and temp 72-74 during the night and 76-78 during the daytime.

I'm running T5's with 4 month old bulbs now, K2 and a K3 each on opposite ends for flow, and a Octopus LX 1000s skimmer.

Oh and occupants are: 1 urchin, 1 peppermint shrimp, handful of snails and blue and red leg crabs, 2 mated clowns, 2 firefish. I feed the fish daily with a quarter cube of mysis shrimp and the corals get feed weekly with target feeding of Coral Frenzy.

I've had the lights on a timer from 10:30 am until 7:30pm for 6 months.


I haven't figured it out, but afraid for the other corals, any ideas folks?

[DC_40gallon]

Bump

[wrott]

More WCs? How do you dose alk/CA? Once you see a decline in an Acropora it is usually too late by about 3 weeks.

[DC_40gallon]

So do more than a 5% water change weekly?

[dead beat reef]

Hey DC
Based on the info. the only big change to your reef are the t5 bulbs.
Diff. brand, new kelvin? I do not know what k2 and k3 mean.
Please tell us more about the bulb change. thanks dbr

[iap]

Bugs? Big temp swings.

[iap]

K2 and k3 are koralia 2 and koralia 3, powerheads. Maybe they weren't getting enough flow after growing larger and died from the inside out.

[slakker187]

yes. the temp swings are more than likely what caused the deaths. also 72 is way to low for any acros that i know of. has the aquarium alway had that big of temp swings or did it coincide with the acros death?

[Specialtang]

I agree with temp swings, I would not let my tank get below 76 and not more then a 1 degree swing per day.

[iap]

^ uhh yea

[thebanker]

Good luck with the remaining corals. The temp is the only thing that I can think of, unless your acros got a disease. Did the dying slow down? What sort of death, RTN, bleaching...?

[thebanker]

Please report spammers instead of quoting them~dc

And thanks you for the thanks you.

[Grant W]

I think the temp is too low I keep mine between 78-80and all is well

[TampaReefer79]

Temp swing is my guess.

Is that a bot up a few posts??

[DC_40gallon]

The two corals died slowly and sped up towards the end.

The acro lost all of its outer color. It just shed off. The birdsnest was a frag and grew fabulously for 6ish month then suddenly the polyps from the inside started to disappear and now it's disappearing up to the tips.

I'll keep the tank at a 80 stable and see what happens.

[DC_40gallon]

The bulbs are 2 ati blue +, 1 Fiji purple and and a actinic that I cant recall the name of at the moment.

[thebanker]

Not the T5 expert but is there enough daylight in your mix?

[Ldesp]

What about salinity as a possibility? What are you using to check salinity, possibly a hydrometer? With such frequent water changes it would be easy for your sailinity to be inching upwards if not accurately monitored. I would suggest a refractometer for checking salinity for more accurate readings.