What do I need to do?

[mkenochm]

Ok I am still having problems with my tank. I had posted in a previous thread that I lost about all of my corals and a couple of my fish mysteriously. Here are the details. I had a heater go out which let my tem in my tank (during those extremely cold nights in January) drop to around 60 degrees. It was only for about 3 days until my replacement heater arrived. About a week after that incident my Nitrates shot up to 150+ ppm and my PH droped to 7.9. I immediately did a 50 % water changed that day and for the next 4 days to get the nitrates back down and buffered the PH using baked baking soda. A few days after the nitrates were back to normal ( less than 5 ppm) I noticed several of my corals were closed up. The next day I had 2 dead fish. I did water test and everything was normal except for the PH it had rose to 8.6. I did another water change to bring it back down to normal. Over the next couple of weeks corals continued to die off. Finally everything stabilized and seemed to be back to normal. The few corals I had left (a weslophyllia, acan frag, mushrooms, 3 heads of a frog spawn, and a few palys) were open and looked great and the fish seemed fine. Day before yesterday now almost a full month after the incident everything is closed up again and today it looks like my Wesophyllia is dying.
I've done water test and this is what I came up with:
Nitrites- 0
Ammonia-0
Nitrates- less than 5
PH- 8.35
Temp- 79.9
Alk- 8.96 dkh
Calcium- 490
MG- 1320
SG- 1.025

From my water test everything seems to be fine. Anyone have any ideas.
I'm runnin a protien skimmer (of course) and it is skimming well and I added fresh carbon last week. I don't know what to do now. Ugh!!

 

[Flavum]

If your No3 is around 150 and ina week drops to 5 I cant imagine thats good for the fish.

How much water did you replace and what kind of test kit are you using?

 

[Engloid]

Thinking out of the box here:

Did you add any new equipment that could have had some toxins in or on it?
Did you maybe put your hands in the tank without washing, possibly having some sort of perfume, deodorant, fragrance or something that could be toxic?

 

[cee]

Baked baking soda is not a good idea for buffering. It will rapidly raise your pH and alkalinity, neither of which make fish or corals happy when done rapidly. That combined with the abnormally high alkalinity of almost all commercial synthetic salt mixes and your large water changes was probably the kiss of death. I would have probably not worried about the pH (7.9 is not bad, esp. in the winter when you don't get as much O2 in your home) and slowly reduced the nitrates over a few weeks. Honestly I haven't checked my tank's pH in probably 3 years and it is as healthy as ever. The next biggest issue to concern yourself with is how did your nitrates get so high to begin with?

 

[mkenochm]

If your No3 is around 150 and ina week drops to 5 I cant imagine thats good for the fish.

How much water did you replace and what kind of test kit are you using?

I did a 50% water change each day. I am using hagen test kits, but I also took a sample to the aquarium to confirm my kits were accurate. I did research on lowering NO3 to quick and everything I found said that NO3's being to high were worse than lowering them quickly.

 

[mkenochm]

Thinking out of the box here:

Did you add any new equipment that could have had some toxins in or on it?
Did you maybe put your hands in the tank without washing, possibly having some sort of perfume, deodorant, fragrance or something that could be toxic?

The only new equipment that I added was the new heaters and about 2 1/2 weeks ago I replaced my rio powerheads with K4's. I rinsed everything before adding it to my tank, but I guess it could be a possibility. I always make sure to wash my hands before messing in my tank and if i've worn lotion etc... that day I weat gloves while working on my tank.

 

[mkenochm]

Baked baking soda is not a good idea for buffering. It will rapidly raise your pH and alkalinity, neither of which make fish or corals happy when done rapidly. That combined with the abnormally high alkalinity of almost all commercial synthetic salt mixes and your large water changes was probably the kiss of death. I would have probably not worried about the pH (7.9 is not bad, esp. in the winter when you don't get as much O2 in your home) and slowly reduced the nitrates over a few weeks. Honestly I haven't checked my tank's pH in probably 3 years and it is as healthy as ever. The next biggest issue to concern yourself with is how did your nitrates get so high to begin with?

Thanks for the tip about the baking soda. I didn't have any buffer and that was the best solution I could find on the web for something I had at the house. A lot of people used it with no side effects, so I figured it was safe.

As to the reason my nitrates shot up to start with, I don't know for sure. My theory is that when the temp in my tank droped so low, for the three days span, it killed of bacteria allowing the nitrates to rise. My tank was heavily stocked. I don't know for sure that this was the problem, but I've talked to several people and researched and this is the best I can come up with.

I may just have to ride this out. Hopefully everything will go back to normal. It just doesn't make sense to me that everything has been fine for the last 4-5 days and all the sudden is not again. Thanks for all the suggestions, maybe if we talk through it long enough it will begin to make sense.

 

[cee]

A lot of people used it (baked baking soda, editor added comment) with no side effects, so I figured it was safe.

My theory is that when the temp in my tank droped so low, for the three days span, it killed of bacteria allowing the nitrates to rise.

It just doesn't make sense to me that everything has been fine for the last 4-5 days and all the sudden is not again.

Not baked, yes. Baked and it is powerful stuff. I use baked BS for alkalinity but would only consider it with a peristalic pump.

Increased nitrates is indicative of little if any anerobic bacteria. I doubt the temp swing killed your anerobic bacteria without affecting the aerobic bacteria. You would have also seen ammonia and nitrite spikes.

I believe it is the fluctuations that are causing your problems. Alkalinity issues usually take a few days to expose the damage IME.