Hard COral Diseases?

[Nexus13]

tank is over a year and half old

the hard corals that died have been in there for over 5 months

all my parameters are good (or so i thought)
pH = 7.9
Ammonia = 0
nitrate = 0
nitrite = 0.1
phosphate = 0
calcium = 380mg/L

yah all my fish are good,
soft corals are fine
just the hard corals all died very quickly.

i looked it up on the net and it sounds like
Rapid Necrosis.

anyone else had or know of this?

in terms of changes:
i did add a neon dottyback
and some porcelain crabs that didn't make it.

[Nexus13]

tank is a 29 gallon with a 10 gallon sump underneath

[fencer]

Yes it is RTN. There is another thread about this happening in the spring. I recently lost two colonies for no reason. Others have had similiar happenings and those people know how to keep SPS's

[findingnemo1]

What is your DKH at?

What do you dose to keep the DKH,Calcium up?

[banditpowdercoat]

You don't have an anemone by chance, do you? My Anemone just made half my Hydno dissapear. Apparently they dont get along LOL

[whatcaneyedo]

How much flow and what kind of light do you have? I've lost hard corals that were receiving inadequate light and flow before. In some cases it took months where the coral barely or didnt grow before it shed off all of its flesh starting at the base.

[Nexus13]

I do have a bubble tip anemone that is pretty small but would have to sting the hard corals wouldn't it?

and it hasn't come near the hard corals

I dont' have a kit for measuring DKH.

I dose with Purple Up maybe every 2-3 days.

I have quite a bit of flow and two T5HO's on it and my corals had been growing quite well with all their polyps out until this sudden dissappearance.

[Marlin65]

Could be a DKH problem you should check that for sure. That being said I lost two out of three caps this spring for no reason at all. Seems to be going around.

[Nexus13]

is DKH the same as KH?

i just was searching through my bucket of aquarium stuff and found a Hagen KH test kit

the KH for my tank was 80mg/L as calcium carbonate

apparently that's low according to this kit.

i'm supposed to be in 105-125

is that accurate?

[whatcaneyedo]

I'm not a big fan of Hagen... A different test kit with units in ppm, dkh, or meq/L would make this a little easier. Also, make sure that your test kit isnt past its expiration date. Are you sure the test kit didnt mean ppm? If its 80ppm then your alkalinity would be 4.48dkh which is really low. You can boost it with baking soda using this online calculator http://reef.diesyst.com/chemcalc/chemcalc.html


"Alkalinity is a measure of the amount of acid necessary to reduce water's pH to the point where all carbonate and bicarbonate have been converted into carbonic acid (about pH 4.2 in seawater). In seawater, bicarbonate and carbonate provide nearly all of the alkalinity. Consequently, reef aquarists can use it as a surrogate measure for bicarbonate and carbonate which are taken up by calcifying organisms (Figure 1). The units of alkalinity can be meq/L (milliequivalents per liter), dKH (degrees of carbonate hardness), or ppm (meaning ppm of calcium carbonate equivalents). One meq/L = 2.8 dKH = 50 ppm CaCO3 equivalents. Seawater has an alkalinity of about 2.5 meq/L = 7 dKH = 125 ppm CaCO3 equivalents."

From: http://www.reefkeeping.com/issues/2005-08/rhf/index.php