Is my 300g tank about to crash ?

[glennhornibrook]

I will try to keep this as short as possible. I will list water parameters , problems and the chain of events leading up to these problems. I would really appreciate any suggestions. I apologise in advance for any late responses but I live in a different time zone in Ireland.

Normal water parameters before 28th Oct (parameters are stable ,except for calcium, )
PH- 8.2-8.3
Alk- 8 dkh
Calc- 380 – 450
Magnesium- unknown
Salinity- 1.0255
Temp 25degC
Nitrate 0 ( at least according to my test kit )
Nitrite 0
Ammonium 0
Phosphate 0

My aquarium is a 300g mixed reef tank. It is sparsely stocked with 3 tangs, 2 clowns, 2 neon damsels, and a goby. Inverts: 8 acros, 2 montis, 1 birds nest, 1 stylophora , 1 finger leather coral, and some other softies like mushroom polyps and star polyps.

Chain of events:

26th October ; added 2 new across, 1 stylophora and a small giant clam ( which was eaten by my hermit crabs the next day. DOH! )
28th October : tested water and got results above as normal . ( calc 380 )
1st and 2nd Nov : PH rose to 8.5 so I tested other parameters.
2nd Nov. : Alk rose to 10.6 dKh and I tested magnesium at 1200 ppm

Symptoms:

1st Nov : Polyps on one established acro and birds nest stayed closed.
2nd Nov.: Regal tang started rubbing against substrate.
4th Nov ; 1 yellow tang showing redish patches on his skin. The other yellow tang has some small black spots on his skin. Goby and damsels are flicking on substrate and an additional acro and star polyps have closed up. The leather coral has completely shrivelled .
This is all very concerning and very unusual.

Things I did out of the ordinary :

1st Sept; Changed salt to new brand with high dKh
2nd Nov: added magnesium supplement ( far less than recommended dose. I rose it to 1215ppm over 2 days. )
31st Nov; used speed glue to attach corals.

Please share any ideas you might have as I’m afraid that things might get even worse.

Regards,
Glenn.

[bertoni]

What's speed glue? Is it just a cyanoacrylate product? If so, it's likely fine. The new salt could in theory be causing some problems, but the corals might have brought along some diseases. I wouldn't worry about a crash, per se, but I'd watch the fish carefully, and get a treatment tank going. Also, I'd run a lot of fresh carbon. Were any large water changes done with the new salt?

[mike_cmu04]

I dont think you are about to crash. It sounds like you just need to adjust to the new salt. The mag level should not be a problem.

[glennhornibrook]

Bertoni,
Speed glue is a gray powder mixed with water that sets rapidly. The brand i used was a German brand called korallen-zucht.de. There is no chemical properties on the label.
I'm not using carbon at the moment, do you think I should start as a matter of urgency or should I be aware of effects it can have on water chemistry. I know it should be changed out in portions rather than all at once so this would suggest possible negative effects on water. The corals bringing disease is very possible and if so also very unfortunate as I have so many different fish and invert symptoms.

I would like to mention that the tank has been running for 3 years with no problems besides the usual start up problems in year one.

Funny you mention the large water change because about 2 weeks ago I accidentaly added about 135g of make up water(salt) to the tank all at once. As I did water syphoned out at the same rate so I did not spot it. It's an automated system that refills as water is taken out. What are your thoughts on this?

mike cmu04,
I hope you are right.

[bertoni]

If it's sold by an aquarium company, I wouldn't worry about it, but maybe I'm being naive.

Large water changes might cause some temporary problems by adding some nutrients and trace elements. If so, the effect should die away on its own.

I don't know why anyone would recommend changing carbon in portions. I always changed all of it. If the tank had a huge amount of carbon, I suppose the carbon might become an important part of the filtration, but that'd be far more carbon than I'd bother using. Carbon is good for a lot of things, and I'd run it 24x7 in that size tank. In smaller tanks, water changes are easy enough that carbon is less important, IMO.

[glennhornibrook]

A day later and water parameters are the same except alk which has dropped slightly to 10.2 dKh.
There is no improvement in the corals, in fact, corals that have been showing good colour are appearing to go brown. Symptoms on fish have worsened and one of my yellow tangs has stopped eating.

I am completely baffled. One week ago all was well and now I'm watching my dream tank unravel in front of my eyes.

At the moment I have QT on standby ( almost impossible to catch fish with aquascape. )and I've started using activated carbon. Besides that i'm testing water daily and observing. I've stopped using any additives eg. kalkwasser , alk-PH buffer.

I'm open to more suggestions and would really appreciate the help.

[HighlandReefer]

"2nd Nov.: Regal tang started rubbing against substrate.
4th Nov ; 1 yellow tang showing redish patches on his skin. The other yellow tang has some small black spots on his skin. Goby and damsels are flicking on substrate"

This sounds like a fish parasite problem like ich.

The coral problem is another cause. Increased lighting (or lighting changes) can cause this in coral. If you suddenly run too much GAC it will increase the light penetration through your tank water and can cause problems for coral.

[bertoni]

I'd get the fish into treatment, if possible.

You could check the polyps at night for any sign of a predator.

[glennhornibrook]

Highlandfeefer,
I think you have hit the nail on the head.
Today I was talking to the guy at the LFS discussing my problem. I did not mention it earlier as I did not realise it's importance but I covered the reflective part of my lighting with mirror(30thOct). It was a dippled type of reflector before.

As advised I lowered ( in the tank )some of the corals that were showing symptoms, in particular the leather coral and the star polyps. I had to leave the house for a few hours after. When I returned most of the star polyps were extended.(no improvement in other corals but it's early days). This would help confirm what you suspect about the corals.( I have to compliment you on your observation of light mods even though you did not know about them . Also I appologise for not mentioning it earlier.)
EVERY DAY IS A SCHOOL DAY..
I started using GAC today ,As you pointed out could be the worst thing I could do.

Bertoni,
It does seem that I have a number of completely different problems at once which threw me off the scent. I have a QT ready to go but catching the fish is a major issue. Black ich would seem to be one problem at least. The red patches on the other tang could be something else.

With your continued help we will get to the bottom of this.

I will decide my next move tomorrow.

[bertoni]

Okay, it sounds as if you have made great progress in understanding the problems at hand! Good luck!

[glennhornibrook]

At least I have some sort of plan now. I'm not out of the woods yet though.
Thanks for your help.

[bertoni]

You're welcome!