Coral bases bleaching, why? HELP!

[acallen]

I have a saltwater tank that I bought off of a friend of mine who propagated the coral himself. I've had it for about a year now, with no problems. No changes in chemistries or temperatures, coral healthy, and fish happy. I am starting to see however, the coral is bleaching at the base. What could be causing this?

Again, no changes in temp, chems, etc.

Thanks:bowdown:

 

[valasaraptor]

pics,types of coral,lighting,placement and perams please....

 

[acallen]

3-T5s, and 8-blue LEDs (at night).

T5s are on 7am-6:30pm.

Corals in question are:

Green birdsnest
Green Acropora
Montipora Digitata
Orang Digitata

They are spaced throughout the tank, in different areas, so I dont think it is a water-flow issue. My tank is a 65-gal saltwater (RedSea).

 

[valasaraptor]

what kind of bulbs and wattage? IMO 3 t5s over a 65g isn't sufficient lighting for SPS corals

 

[acallen]

3 - T5, flourescent lights (234 total watts)

 

[acallen]

If its a lighting issue, why is it bleaching at the base all of a sudden? I've had the tank over a year, and its just now become an issue~ all i can think is its a bacterial infection?

 

[valasaraptor]

Thats about 3.5 watts a gallon id shoot for 6 or more for SPS maybe a lil less because there easy SPS but I really don't think the lighting is adequate.

 

[valasaraptor]

how big are they? whats your calcium at? and other parameters

 

[acallen]

Ammonia = 0
Nitrate = 0
Nitrite = 0
pH = 8
Temp = 80
Ca = 350
Mg = 1200
they're maybe 5-7 inches tall

 

[valasaraptor]

Hmmm im not really sure then? pics might help but I only have basic knowledge on SPS
others will chime in soon.

 

[fastrd400]

Are there any other corals around them/touching them? Mushrooms, etc?

 

[Marines_Wife]

Were they just fragged out??

 

[acallen]

They were not fragged, nor are they touching the glass or other coral species.

 

[Northstar24]

How old are the bulbs in your fixture? The spectrum in T5 bulbs changes, and the output fades as they age. Depending on who you talk to, you'll hear that T5's should be changed somewhere between every 6 months to a year. I think the better quality bulbs can go more towards the 12 month mark, while the cheaper bulbs are more towards the 6 month mark.

 

[acallen]

I'll change my bulbs, its probably been a little over 6 months~

 

[BL1]

What is your Alk readings? I believe I remember another thread where someone attributed SPS bleaching at the base due to low Alk readings.

 

[Smitty]

What is your phosphate level reading?

 

[sen5241b]

1+ Smitty I DO NOT SEE A PHOSPHATE TEST! One part per four million will cause acropora and your other corals to bleach!

 

[parrotchute]

How big are the corals? Another possible explanation is that if they are growing and shading their base, it could be bleaching due to lack of light.

and the watts per gallon rule makes no sense - the depth of the water and the surface area vs. the PAR is really what is more important.