STN - Encrusting LPS

[aaron1987]

I have an established 25g mixed reef that's been up for approximately 3 years. Over the past few months I've been observing something new. My encrusting LPS corals are generally quite happy but lately I've noticed the beginnings of a slow necrosis in my cyphastrea and chalices. Two months ago I couldn't frag and dispose of them fast enough, but my entire 12"+ colony of meteor shower cyphastrea is toast and my chalices seem to be headed the same direction. In these instances, I would liken the recession to something akin to being stung by an encroaching coral... but that isn't possible in any of the cases (no neighbors, docile neighbors, effects spread throughout the tank). For example, I have several colonies of Miami Hurricane throughout the tank all are behaving the same way.

What makes this frustrating is that my parameters test normal and the majority of my corals are perfectly happy (blastos, mushrooms, acros, zoas, etc.). I've done the normal thing and increased my water changes and examined the corals for pests, but neither has led to any leads. Any ideas? :headwally:

Edit: I run carbon, GFO, skim at a moderately aggressive rate and run LED lighting. I run Seachem Reef Salt; halfway through the bucket and if memory serves I've been using this one since before my issues started.

 

[Reef Frog]

Both corals you mention need surprisingly low light levels to do their best. I scorched a few chalices before I realized this, even under a T5 fixture in my case. Very low nutrients could be another cause or a contributing factor.

 

[aaron1987]

Both corals you mention need surprisingly low light levels to do their best. I scorched a few chalices before I realized this, even under a T5 fixture in my case. Very low nutrients could be another cause or a contributing factor.

Agreed they are both low light corals. Both have historically been extremely happy in my system and, as they encrust, I haven't moved them at all. The light is an interesting thought, as my Kessil 350w is going on 3 years, but if the spectrum or intensity were degrading I would expect to see my SPS lose coloration, or some sort of reaction from my other corals.

Has anyone heard of lack of space causing a coral to crash? While not true for my smaller, distributed chalice colonies, my large cyphastrea colony and large hurrican chalice are both pretty much at maximum size. I've never experienced or even heard of something like that before, but I'm at wits end. I should mention when I noticed the cyphastrea receding I fragged a healthy piece and relocated it to the other side of the tank with similar lighting and flow... it too is receding.

While my parameters are testing as normal, I'm sure I have some nitrate taken up in small outbreaks of bubble algae and a bit of cytobacteria I've seen flare recently. Given the bit of nuisance algae I wouldn't classify the system as ULNS - My girlfriend is fond of feeding the sun corals...

Recent additions have included some assorted zoas, but they aren't located near the colonies in question.

 

[ghostman]

What are your parameters, especially magnesium? My chalices seem to show some recession when my magnesium level is low, particularly after a water change since my salt has low mag. My chalices seem to like lower alk as well, and I keep it around 7.0-7.5.

 

[aaron1987]

A bit of an embarrassing update; but what else are forums for. Despite my confidence that my parameters were still stable from my last measurement as my most delicate corals were happy I tested anyway. Parameters: 1150mg, 5.4dKh, 450Ca. I'm surprised none of my other corals are reacting to the dramatically low alkalinity but it looks like that's the most likely culprit.

 

[ghostman]

Glad you got that ironed out. Luckily LPS can recover quickly. Go slow with the shift back up. What do you usually keep your alk at?

 

[aaron1987]

I try to keep it around 8; in this tank I've had issues keeping it elevated... Opposite problem I used to have, and an odd one given that seachem reef salt generally has pretty high alkalinity.

 

[Reef Frog]

Nice save!

I let my magnesium slip once to levels even lower than you found. A nice dragon soul favia started looking bad...sort of the canary in the coal mine. I fixed the mg of corse & fed it and it is largely recovered now.

Since the incident it also seemed to do better in a little less light as well. During recovery I let nutrients raise a little by backing off on GFO & heavy wet skimming for a while. Colors improved & long dormant zoos & a few mushrooms came back to life. Sometimes I wonder if a given problem often has multiple causes contributing to the issue. It's hard to tell when you employ multiple tactics all at once.