Tank Crashing

[theguy67]

Hello everyone. I am experiencing some sort of ‘crash’ that I’m trying to sort out.

System: 13 gallon softy tank. Set up last summer from an existing 10 gallon.
Inhabitants: colt coral, sinularia, several mushrooms (over 30) 2 toadstools (small) and a frag of acans (only non-softy). Everyone has been doing great, with excellent polyp extension. One sexy shrimp and one emerald crab plus various small nerite snails.
Filtration: weekly water changes and HOB filter along with vacuuming of sand (crushed/large grain). I ran the nano before this one the same way without issue.
Feeding: alternate between reef chili and coral cuisine 1x per week

Parameters on 1/18/2026

Nitrate 0​

Alk. 8.6​

Cal 330​

Mg 1260​

Sal 1.025

Phos 0

pH 8​

Temp is 77-79 through the day
Ammonia 0

I noticed the alk and cal were drifting down compared to 3 months ago, so I dosed to increase a tad. I dosed over the course 2 days via the top off water fed by drip. Alk increased to 9.3, but calcium jumped to 560 (sailfert dilution test). Mg was also increased a bit to 1400.

Everything was ok until a couple days later when everyone was not opening as much, and each day it was just more and more closure until now everyone is closed.

Parameters on 1/23/2026

Nitrate 0​

Alk. 9.3​

Cal 560​

Mg 1420​

Sal 1.025

Phos 0

pH 8.12​

Temps the same 77-79
Ammonia 0

Since the reaction was slow, and I was gearing up for an ice storm, I didn’t test right away (another mistake).
I definitely overshot on the calc, rookie mistake. And I understand my alk is a bit high; however, it was running in the low 10s last fall so I let it drift down a bit. I wanted to raise alk to the low 9s and cal a bit as my acans were growing well until things dropped. I did a water change, Calc dropped to 485 after the above testing was done. Alk was 9.3. I didn’t test anything else that night.

Parameters on 1/26/2026

Nitrate 0​

Alk. 9.6​

Cal 475​

Mg 1400​

Sal 1.025

Phos 0

pH 8​

Temps the same 77-79
Ammonia 0

Above was a few days ago. Things didn’t look great but not awful. I figured I would just let things sit and hope it was a mild reaction.

I haven’t touched the tank, other than adding pure distilled water, as I didn’t want to shock it again. Just let everyone settle to the new numbers.

Today I sit as my mushrooms melt, my colt coral is sulking and my small toadstool melted at the base. I haven’t rested, but I did check ammonia, it is 0 still.

I’m very confused as to what’s going on. I don’t see precipitation (although it could be mixed with the algae bloom). It looks like a full system crash, but everything I read says a calc spike wouldn’t cause a huge stress event. And an increase of 1 unit of alk over 2 days shouldn’t be a big deal? Especially for softies? Ammonia is also 0. Was it a compounding of events? Ionic shifting in water chemistry causing global stress?

I’m doing a water change tonight. Just looking for possible theories at this point.

 

[wvned]

Could the power have gone off while you weren't there. I would suspect something like a temp swing over a slight shift in water paramaters for so many things to be affected and some hardy ones melting.
Carbon, water change and stability and hope it stops is your best course.

 

[griss]

Could the power have gone off while you weren't there. I would suspect something like a temp swing over a slight shift in water paramaters for so many things to be affected and some hardy ones melting.
Carbon, water change and stability and hope it stops is your best course.

This^

FWIW I’m dealing with a similar situation and my tank has been running since 2017 and I’ve been in the hobby since the 1980s. Unfortunately, these things sometimes happen.

 

[theguy67]

Could the power have gone off while you weren't there. I would suspect something like a temp swing over a slight shift in water paramaters for so many things to be affected and some hardy ones melting.
Carbon, water change and stability and hope it stops is your best course.

That’s what it looks like and ironically what I feared with the storm. I started seeing issues last week (like 1/20), and it was a gradual decline since. If I did lose power, I would have noticed my light’s timer being off schedule.

My only thought was maybe I set the tank’s heater in the mixing water bucket too long? But why would it be such a delayed reaction if temp did dip for a couple hours (max).

It’s sad, the Colt was so pretty.

 

[theguy67]

This^

FWIW I’m dealing with a similar situation and my tank has been running since 2017 and I’ve been in the hobby since the 1980s. Unfortunately, these things sometimes happen.

Thank you. I’m hoping I can discover what went wrong so I can move forward with this tank.

 

[griss]

Thank you. I’m hoping I can discover what went wrong so I can move forward with this tank.

That’s the tough part of this hobby, everything is going great and suddenly disaster. Years ago, I had a breaker trip and I ended up filling a 30 gallon trashcan with SPS skeletons. Almost all I had grown to basketball size from frags or small colonies.

 

[wvned]

I had an extended power outage. My tanks got down to about 73 by the forth day then the power came back on. 3 days later 90% of my xenia died and a few other things.
I think it is the extent of the deviation and not how long it happens that matters to some things.
And I could be completely wrong. I hope it never happens again to find out.

 

[theguy67]

I had an extended power outage. My tanks got down to about 73 by the forth day then the power came back on. 3 days later 90% of my xenia died and a few other things.
I think it is the extent of the deviation and not how long it happens that matters to some things.
And I could be completely wrong. I hope it never happens again to find out.

That’s fair. I also burned rice accidentally in the kitchen, although it was like 3 weeks ago. I also used a coffee filter to measure out the magnesium and calcium supplements. Maybe I stuck my hand in there after touching something toxic. I suppose a contaminant could have been introduced at some point.

 

[theguy67]

That’s the tough part of this hobby, everything is going great and suddenly disaster. Years ago, I had a breaker trip and I ended up filling a 30 gallon trashcan with SPS skeletons. Almost all I had grown to basketball size from frags or small colonies.

Ahhhh that’s tough. I couldn’t imagine dealing with that loss. This hobby is not for the weak. I do appreciate your support.

 

[wvned]

Over the years I have read many posts like yours. The truth is there are an almost infinite number of things that could do it. Many no one would ever think of.
thus my original post
Carbon, water change and stability and hope it stops....
A long time ago I had a heater fail and burn. I thought all I had to do was replace the heater. It decimated my tank.
No. Not a hobby for the week. 3 weeks ago we walked in and one of the eels was laying in the floor not moving. I pitched him back in the tank.
Dog hair and all. And waited.
He lived. You never know. Sometimes you get lucky.

 

[griss]

This is a good conversation for people new to the hobby to read. Stuff happens, things die, you either quit or forge forward.

 

[theguy67]

I have just completed a 2 gallon water change. I may schedule another in a few days as my theory is now leaning toward contamination, even if an increase in nutrients.

 

[griss]

I have just completed a 2 gallon water change. I may schedule another in a few days as my theory is now leaning toward contamination, even if an increase in nutrients.

As my friend @BrianD used to say, “dilution is the solution to pollution” or something like that.

 

[brandon429]

How is this tank is it still good or problematic

In the description there are specific things causing the crash that can be undone if not too late. *patterning your care routine off 20 year old uncrashable nanos is the right way to fix, there's specific actions you can take to prevent this in the future if not too late

The method you're using isn't found in super old nanos it's the common approach that gives an avg 3 year lifespan. There are opposite things you can be doing that give amazing lifespan

Post a tank pic let's see status

 

[brandon429]

When you adjust UP any alk setting and keep your lighting unadjusted that begins bleaching risk. There's an opposite way to handle this issue vs the common way, pics will tell not parameter levels. There's a few other approaches that can be changed for better lifespan, but this is the main one for you because bleaching and loss and adjusting alk based on small changes perceived was mentioned.

Knowing when to reramp your lighting to stop bleaching vs 100% not ever altering light power in reaction to tank needs: longevity trick #1

Pics will show if this tank needs calcium and alk testing -at all-

(we're looking for % biomass of corals in the pic that would command calcium and alk from the water)

Is the tank full antler sps colonies aged and hungry? Or is it a few frags with not much overall command in the water?



Pics will show the need for testing and dosing : not the test levels rendered by nondigital hobby kits for calcium and alk.


take time to search out threads here and other forums where readers take 2 or 3 different alk test kits, and run them on a given sample to check for consistency. Note the range of readings presented.

What if your levels weren't low and you were adding alk where it was already OK? This is why minute testing and response isn't part of old nano reefs it's a temp game to play

How you handle the tank on the macro level is how you age it: it isn't in attaining exact param levels

when we see a greater tank symptom in play we tend to grab onto test kits to hopefully stop the loss, ammonia is #1 Im fully amazed you're reporting zero on a hobby nh4 kit. They usually report low levels as nh4 runs ten times that of nh3 for a given sample. If it helps to know: at no time do you have to test a nano reef for ammonia if you can account for all the fish. It's not possible for ammonia ever to be a player if no fish are rotting, no other cause exists in reefing to require us to test for ammonia.

The zero ammonia reading is odd. One of these days when you test and it says .25-> it's still not an ammonia problem. Expect variation in readings it won't always be zero and don't try to make it be zero if it isn't. Ammonia anxiety is the #1 testers habit in reefing, ditch the kit and don't run it on your tank if you want longevity.

At any time your reef seems in peril it will never be ammonia causing it. This saves you from reactively adding bottle bac and prime (oxygen saps) into a stressed tank. These actions come from test and response training, which isn't part of long term nano reefing. It's part of short term nano reefing.



Also unique in super ager nanos: what you do if you suspect a contaminant.

I don't think it applies here; but there's a specific set of actions ran to save the tank when this applies as trick #3 not mentioned so far. A small water change isn't much help for a contaminant but there's not one here most likely. Pics of the tank show what we need to see to get it back on track. Another thing we'd look for in pics are animals that will die first during a power outage if present, helps to gauge % likely that such a cause was your bleaching issue.

I predict no outage happened here. Seeing the degree of waste or cleanliness in the sandbed from the pics is part of troubleshooting, at no time are relayed param levels factored into anything to help your tank.

Stated test levels do not factor at all, at any time in nano reef troubleshooting. Only pics of the tank matter. The only params we need for you to impart are a workable salinity and a decent temp, the rest are actions you take that require no measure.