Translucent tips after signs of growth

Fringe09 · May 3, 2019

Hi fellow reefers,

Besides Alk swings, what are some reasons SPS corals can get translucent tips after signs of growth?

My 200g (160g display and 40g sump) has been up for 1 year and 8 months now. Some of my SPS higher in the tank are having this issue and I am not able to find the root cause.

Here are my current numbers:

Alk: 8.1
Ca: 410
NO3: 2
PO4: .03
Mg: 1400
Salinity: 1.026
pH: 8.1 to 8.4 depending on the time

Dosing ESV B-Ionic throughout the day using Neptune DOS.

10% weekly water change using Tropic Marin Pro.

Running four Radion XR30w G4 Pros at 50% using RMS mounts which have not been changed since first setting up the tank.

Waiting for results of another Triton ICP and N-DOC tests. Did it three months ago and nothing out of the ordinary showed up except low iodine.

Started using Coral Vitalizer and Amino Acid Concentrate from Korallen-Zucht 12 days ago to see if it will help. So far I’m just seeing more polyp extension from most of my SPS, LPS, and soft corals.

29bonsaireef · May 3, 2019

Can you describe in more detail how they are translucent? Not sure I have ever seen a translucent acro. Is there still living tissue on the tips?

Fringe09 · May 3, 2019

29bonsaireef said:
Can you describe in more detail how they are translucent? Not sure I have ever seen a translucent acro. Is there still living tissue on the tips?

Almost seems like see through. Like a hollow skeleton.

29bonsaireef · May 3, 2019

Sounds weird, have any pics? Could just be the new growth. I have a lot of corals where the tissue is sort of translucent on new growth, but I wouldn't consider the coral translucent, because I can't see past the actual hard skeleton.

Here's an example where the tissue looks somewhat translucent. The cause of this for me is extremely low nutrients, and really high par

najer · May 4, 2019

Nothing wrong with that imo, nice healthy growth.

Softhammer · May 9, 2019

Most fast growing acroporas look like that when doing well. The tips grow faster than the zoozanthellae can populate the tissue. 100% normal, and a good sign.

Fringe09 · May 9, 2019

Softhammer said:
Most fast growing acroporas look like that when doing well. The tips grow faster than the zoozanthellae can populate the tissue. 100% normal, and a good sign.

That was my hope. First I saw white tips and then it looked translucent. About a week later, algae started growing on it. I did a Triton N-DOC and ICP test. Only three issue they pointed out which I am correcting now. Not sure if they are the cause.

Low Magnesium. 1313 ppm
Low Potassium. 362 ppm
No Iodine.