All my corals are dying all at once!

[Amysan]

All my chemistry in my tank totally checks out as a healthy tank, even when checked at the same time of day! But, my corals are turning white and eventually dying what is going on? Help! I also have what I think is red algae in the tank which I had never had before! I have softies and hard corals! I also have reef safe fish that I don't want to die! I am using a protein skimmer on my 79 gallon tank which has always supported my corrals, but I don't know what happened! What steps should I take? Pictures of the healthy tank and now the sick tank!
Any and all help would be much appreciated, new to this website!

 

[Elitehunter1]

Did u recently change/add something? Lighting, fish, rock?

 

[Elitehunter1]

Kinda looks like cyano or red slime.

 

[Amysan]

None of the above added!

The only chemical added was a buffer to get the PH to a good number
but other than that nothing! I can only imagine that in some
way the buffer had something to do with it even though we
followed the directions exactly! The addition of the buffer is the only
event that seems to somewhat correlate with the massive coral
Death, but I don't know if this is possible or even probable!
Thanks

 

[Amysan]

How do you go about treating red slime or cyano and are the different?

 

[Elitehunter1]

Well first thing for your situation I think most would recommend a good water change. How often do you do water changes? And then as far as the cyano- I had a bad problem with it in my reef tank and another 55 g system I use for seeding live Rock. I used chemi clean, you follow the directions, wait like 48 hours and do a water change. It worked like you wouldn't believe. 100% eliminated, I think it was like 25 bucks

 

[joy13]

I have more problems with adding buffers and get the the same effects on my corals. Instead of using buffers I do water changes and it helps with the ph and the cyano. You do want to either use chemi clean to get rid of it or do water changes sucking it out as much as possible.

 

[ccCapt]

You have a very high nutrient level in the tank just by looking at the "now" pic and seeing the cyano and nusiance algae.
What, exactly, are your water parameters?
nitrate -
phosphate -
alkalinity (since you are adding buffers) -
pH (since you are adding buffers) -
salinity -
How often do you do water changes and how much do you change? Do you use RO/DI water, tap water, well water, etc. for water changes and top offs?

 

[TeamTrash]

The only chemical added was a buffer to get the PH to a good number
but other than that nothing! I can only imagine that in some
way the buffer had something to do with it even though we
followed the directions exactly! The addition of the buffer is the only
event that seems to somewhat correlate with the massive coral
Death, but I don't know if this is possible or even probable!
Thanks

Be careful with the buffers. It increases your alkalinity, which in turn will lower your calcium. I'd check your calcium levels and take it from there. Personally, I did a big (40%) water change to get my alkalinity from 13 to 10. Now I'm keeping my eye on calcium that was at 300... oh, and after the large water change my ph magically stabilized at 8.0.

 

[joy13]

You don't want to change your ph or any of the parameters to fast, it can make things worse.