Why Do SPS RTN?

[ScubaShane]

I had an acan at the bottom of my tank devour my purple bali acro at the top. My tank is 29" high. The acro was up around 23" to the top. It was about 11pm and my moonlights were on. I went to go get some snacks and looked in the tank on my way and saw a big ball of spermy stuff. Then when I took a closer look it was the acans guts eating the crap out of my acro. It was like somthing from a sci-fi flick. Gross and cool at the same time. My acro was about 8" across and gone complety at 5am. Sold the Acan! Didnt want to loose my red planet! ............so if you have any LPS in your tank you should stake out one night or setup a web cam.

 

[mtnrunner]

I recently lost a small millipora to RTN. It was growing great and had it for 2 months. No new corals or fish added. Parms in check. The only swing was temp. Heater set at 77, plus or minus 1 with controller. Unit went bad but temp only went to 79 when I caught it and replaced. Was 79 enough of a change to trigger RTN?

RTN started at a top tip and spread killing the 2" coral in about 2 days.

Any relation, thought or anything whether RTN starts at top or bottom of coral? I've seen both mentioned.

RTN is still a mystery it seems to our hobby. Hopefully we will find hard facts to prevent in the future.

 

[KoleTang]

Just a thought, but the 'starving to death' theory makes most sense. Maybe so wine with a current case of RTN or STN try running a slightly dirtier tank. I wouldn't let the nitrates go above 20 and phosphate above .1, but if you're after a 0/0 tank, that could be the cause. I'm sure there are many reasons that contribute to RTN and STN, but if the diet is weak, then any species would struggle to recover from even the slightest amount of stress. Think about it, in the oceans these corals come from, nitrate levels can be as high as 40 (from what I remember reading) and never 0. They NEED some nutrients in the water column to thrive. Just my $0.02

40 is unheard of in most natural reefs. 0.1 ppm is common in shallower water (where most of the corals live). 0.5 - 2.5 in deep water. The thing that uses nitrate in a coral is zooxanthalae algae, but it doesn't need much and it can stunt the corals growth at levels higher like 0.9 ppm (depending on things like alkalinity).

If you aren't running an ULNS, you won't ever get lower than 0.1. In most cases, people who know how to properly run ULNS will aim for 0.1 ppm - 0.3 ppm. So there is little risk of starving your coral of nitrate unless you do something like over dose a carbon source. I do agree that starving the corals is a possibility, but unless the system is carbon dosing, I'm not looking at nitrate as the thing that is too low. The main thing people starve their corals of is organic materials (Fish food, coral food, fish waste, etc.). In the wild, 1 cubic meter of coral has been measured to consume a pound of food per day. (144 cubes of food) No where near what our corals get.

(Aquarium Chemistry: Nitrate in the Reef Aquarium ? Advanced Aquarist | Aquarist Magazine and Blog)
(Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com)
(Home blended coral food, (used to be $5) - Page 3)

 

[TVo]

So this happened to me overnight. The only sps affected were my tenius. Everything else was stressed but did not peel away like my tenius did. Alk and ca monitored by trident (calibrated) recently. Temp did not swing. Everything was healthy with beautiful colors and PE, then boom! Gone. I did put some new Indo sps in the tank but it’s been over a month and nothing happened until now. I also dosed chemiclean but I’ve done that many times before as well. Reading through this thread a lot of it makes sense. Maybe a new strain or bacteria that took over once I killed off other strains with the chemiclean? Also I haven’t changed my filter membranes on my rodi unit in a while. Can that be the problem ? So frustrating