coraline algae turning white quickly? help!

[confusedfishy]

Hi,
Any help would be great, I have a tank that I have had for 2 months, it was bought from another person, so it was established. I have live rock that is covered in coraline algae. It has been increasing all over the rocks, tonight, over the last 2 hours I have noticed alot of areas turning white. Nothing has happened inside, I did the last water change nearly two weeks ago. I tested everything and the levels are:
salinity-1.022
calcium - 500
nitrite-0.0
ammonia-0.0
phosphate-0.0
nitrate-10.0
ph-8.4
temp in tank is about 79 degrees

 

[stephish]

When you top off with straight RODI (no salt in it) does it come in contact wtih the LR? I've had this cause what you're describing when I got a bit over zealous pouring the top off water in.
Also, what are your tank inhabitants? urchins and some other critters will eat your coraline.
Is your pH normally 8.4? it's just a touch on the high end of the scale.

 

[stephenthefish]

if the coraline comes out of the water for too long it will turn white. Happened to my power head during a water change when i had to fix it. RO water makes sense if it hits it hard too

 

[confusedfishy]

We have a RO system that we use and we have been using a Kalkwasser system. The water is alittle too high right now, we are trying to establish a good constant flow amount.
The Ph is normally about 8.4, it has been that way for at least a month or so for sure.
The inhabitants are: 4 snails, 2 shrimps, 1 mushroom coral, one clownfish, hermit crabs, 1 starfish, and some other type of small crab. These have all been part of the tank for some time, the mushroom coral and starfish are new by about a month.

 

[ibew]

whats your alk/dkh reading your alk probalbly is low being that your calcium is high at 500 they work hand an hand. If calcium is to high alk will be to low an vice versa. But you will from time to time have alittle die off of coraline

 

[dennis210]

Using Kalkwasser - if you did "drip" it in too fast and raise the level of water that is too muck kalkwasser to quick. pH could have gone up and bounced back. Really need to know your alk / dKH reading.