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.

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.

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.

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?

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

I can't believe the DkH is that low. I would find a LFS and get them to verify the carbonate hardness. Edmonton water is already hard( unless of course you are using RO/Di water) and plus fact that he is dosing with a calcium additive

The thing that jumped out at me in your posts were that you lost a couple crabs....how old and what brand of test kits are you using? First thing I would do if you wanna keep sps is invest in some quality test kits (salifert or elos) dkh, mg, ca and ph. ( I personally wouldnt bother with a phosphate kit).

yah all my kits are hagen ones.

didn't know those thing expired

:redface:

are Seachem test okay?

this one looks like it would do my Mg, and alkalinity in one.

http://www.jlaquatics.com/product/t-...+Test+Kit.html


ELos kits are really expensive!

I would aim even higher than that. 140 ppm is roughly 8 dKH and that is where I like to be. 80 ppm is about 4.5 dKH which is way to low for SPS.