Receding monti

[christan1959]

Hi there. Anyone knows why two of my montis - a red one on the left and reverse sunset on the right - are whitening from the edges?

All other corals ok.

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[christan1959]

Hi there. Anyone knows why two of my montis - a red one on the left and reverse sunset on the right - are whitening from the edges?
All other corals ok.
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kH and Ca hv been stable.

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[JMW]

Looks like new growth. Take a close look, you might be able to see at these white regions, small white polyps which confirm that the monti is growing. 

[christan1959]

Not new growth. Receding.

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[christan1959]

Shld I cut off white portion to prevent it fr spreading further? Anyone experienced this b4??

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[cedricang]

Chris, imo there are few possible reason.

1. Monti pest - monti nudi could be present, please check if you see any such whitish furry small specks of crawling nudis, if have, then you need to treat it.

2. Lack or too much of potassium level - check for potassium level, should be around 400

3. Kh - alkalinity level too low would also cause such receeding symptom

[christan1959]

Tks Cedric.
I've considered pests but cldnt find any sign.
Potassium: should it not affect more sensitive SPS first? Montis supposed to be hardy.
I've actually narrowed it down to stingers from neighbours.
I've put a bag of activate carbon in sump. Let's see if things improve.
I've also started new frags from the unaffected parts. They're doing well (so can't be potassium).
Will keep u posted.

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[cedricang]

Most welcome, keep us posted

[sleexox]

Updates on your monti?> 

[christan1959]

Recovered liao 

Tks for asking