coral fading

[jc]

I have two corals that aren't looking so good. First my blue slimer has lost some color near the bottom of the main branch.
http://i314.photobucket.com/albums/ll412/jc1of2/IMG_0002.jpg

Second, my acropora valida is loosing its blue tips. I have a second smaller piece that seems to be fine.
http://i314.photobucket.com/albums/ll412/jc1of2/IMG_0003.jpghttp://i314.photobucket.com/albums/ll412/jc1of2/IMG_0005.jpg

The only thing I have been doing different is that I haven't used phosban in about a month. However, my cheato has doubled in size.
Here are my parameters as of today: alk 2.25 meq/l, nitrate ~2 ppm
Last week my calcium was 360 ppm.
My ph meter ran out of batteries, but I use top off water with kalk in it. November 2nd was the last date with a ph reading and it was 7.9. Also, my magnesium was 1500 on November 2nd.

Any ideas why this is happening?

[aquasport24]

Check for red bugs..

[glennr1978]

phosphates, nitrates.

[CoryDude]

Check your phosphate levels. I'd also re-check that ph. Then I'd look at things like: age of bulbs/tubes, any water flow changes, pests, etc.

[Jeff]

it doesn't look to be redbugs from the picture as you would see some around the white area. i would change the batteries and get your ph meter back online. also since you are no longer using phosban and your cheato has increased you have a change in nitrates.

[jc]

I checked my nitrates yesterday with a salifert test kit. Nitrates are around 2 ppm. I'm pretty sure my phosphate kit is not accurate so I went ahead and added some fresh phosban day before yesterday. Still not sure about the ph.

[jc]

Just checked my ph and it is 7.9.

[Bill S]

JC, what bulbs are you running? I've found that my Helios 20Ks, while they make corals look nice, I'm losing all my violet colors. My valida is barely blue at all. Under 14Ks, it was deep violet.

[jc]

I use t5's. They are about 4 months old.

[jc]

My xenia are not opening now. They have been closed for 4 days. Could it be related?