KH Issue

[megos1]

A friend of mine has a 90 gallon reef. The tank is well established but he is all of a sudden running into a KH problem. Every time he tests his KH he gets a reading of 9, (90). He is adding Seachem's Reef Builder (1 tsp/40 gal) so 2 tsp at least 3x week and his KH never reads differently. His Ca is 450 and we are currently unable to test the Magnesium until the test kit comes in but he is adding some just incase. The pH maintains itself at 8.3-8.5 despite the KH trouble.

Any suggestions would be greatly appreciated! (Especially by the dying pink birdsnest coral )

[sooju]

The target range for alkalinity is 7-11, what is the problem with 9?

[megos1]

I just did some research and you're right about the target alkalinity. We read elsewhere that the target should be between 12-14 and aimed for that for the past few (years, lol.) Any ideas as to why the SPS are dying? Lights: 2, 250W halides, (4) 65W actinics. Plenty of flow. All other parameters are perfect.

[Kurt_Nelson]

Originally Posted by megos1

... All other parameters are perfect.

How about some real numbers? As you found out first-hand with your KH question, some folks' definition of "perfect" are different than others! Also... what specific SPS is your friend having a hard time keeping alive and is this a sudden/recent thing?

[megos1]

pH: 8.3
NO2: 0.1
NO3: 5
Today the KH was 11, Magnesium 1600 and Calcium 600 from adding everything to try to get the KH up. Sigh.
He's new to SPS and is losing the birdsnest he's had for about 2 weeks. All of the fish, LPS and soft corals look fine. This is all a sudden problem.

[Kurt_Nelson]

Hmm... y'know that ANY detectable nitrItes aren't good for coral, right? Maybe a testing error?

That calcium is really really high and way out of balance with the kH. I don't think it has the potential to kill off coral, but it does lead one to wonder about other things that may be out of balance too. Yeah... I know he's been adding stuff to get the kH up, but it just may have thrown everything out of whack. I'm not an SPS guru, but I know they're a bit more finicky than LPS. You might forward this link along to help him get his water parameter back in line...

Chemistry and the Aquarium

Better yet... have him join the site so you don't have to be the "in between!"

So it sounds like it's just one SPS (the birdsnest) that's dying? If so, and he's only had it for 2 weeks, I wouldn't necessarily assume something is bad with the tank/water. It could just be bad luck, or poor acclimation/shipping. How exactly is it dying? Or is it just bleaching? If it went from one type of lighting to a much brighter lighting scenario, it could just be stressed due to the sudden change.

I'm assuming salinity is around 1.025 and temp around 78-80 or so, since the LPS are all doing fine?