Coraline Algae Die off

[fpats]

Hi all,
Wierd stuff is going on, My tank is about 6 years old and has gone through quite a few transitions. Well I notice something the other day and it seems to be spreading. I saw what looked like light pink coraline algae but what it really was is die off because over the next day or so it turned white.
Now I checked all my params. yesterday and they are all fine PH 8.1-8.2, Amo. 0, Nitrite
0, Phos. 0 Nitrate 30ppm to 40 ppm. (iknow they are a little high but have been dealing with this for years)Cal. 400ppm. Salinity 1.022-023
Now I have never really had a coraline die off before. Does this happen as a normal occurance?????? With Age?????????
This stuff has completely covered my back wall for 3 to 4 years and now it seam to be dying off, I have a little concern. I know it isn't the Nitrates because like I said before
I have always had higher nitrates and it never effected this stuff for all these years. SO any help would be appreciated.
Thanks
FP
Tank: 45 Gal
Fish: 2 percs, 1 blue damsel (gold Tailed)
Inverts: Button Polyps, 1 colt, 1 green brain
Frilly and metallic Mushrooms, Green Star polyps, 2 cleaner shrimp, bunch of snails and crabs and 1 brittle star
Rock: 50lbs assorted LR
Equip: Lights: 96 watt 8800k daylight PC, 60 watt no flor. ACTINICS
fILTER: 10 gallon sump, 20lbs LS, Refugium, mag7 return, CPR Bac Pak, Coil Denitrator

 

[burnnspy]

You didn't mention the second most important factor in coraline algae survival, Alkalinity.
BurnNSpy

 

[seabass]

This might sound funny but I used to have 2 75 watt MH and 1 floresent 50/50 and 1 40 watt floresent 40 watt. I than changed my 50/50 to a blue and WOW did I ever notice the diffrence in growth of corline algae in the first two weeks. My point is did you do a change in lighting.

 

[starfishjackedme]

Something else not mentioned is that new commercial salts have 1/2 the magnesium in the mix so it will disolve faster (Instant Ocean incl). After finding that magnesium is direclty responsible for the solubility of calcium I added a magnesium supplement. The Purple has to have this to sustain itself. Anyway, I could not figure out why purple wasn't spreading in my tank even when dosing Kalk, until I added a magnesium additive, then it grew like crazy.
[ December 13, 2001: Message edited by: starfishjackedme ]

 

[fpats]

my alk was 2.9 but I did buffer a little tonight, like I said I have never had this happen before and I do have about 6 years of experience to boot. I Love this hobby learn something new every single day.
Any more thoughts would be appreciated.
Thaks Again
FP