DSB gone bad

Marvin

Marvin

MyPetPugMilo
Dec 17, 2003
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Irvine, CA
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Hello everyone.

my specs first:

37g tank
Fluval 304
NO lights (flourescent)
2 clowns
1 yellow tang (tank too small i know)
1 powder blue
1 golden head goby
5 snails

Last Thursday i attempted to take out my crush coral to put in some HD sand. I first took water samples and everything was normal. I then placed about 1/2 of my water, 35lbs of LR and all my fish and snails into large plastic container. I also placed an airstone and heater in the container. I proceeded to take out the remaining water out to dump. Next I removed all the CC. I then cleaned the tank a bit to put in the DSB, about 3-4 inches. I then added about 20g of Salt Water (from LFS) to my 37g tall tank. I let the sand settle overnight.

The next morning, Friday, the water was still cloudy so i waited.

On Saturday morning (water still cloudy), i decided to add my base LR cuz i knew it will kick up some dust.

Saturday night (water a little clearer). I started up the canister to see how that affected the dust. Moved the dust a bit but wasnt too bad so i left it on.

It wasnt until Sunday that the water cleared. I then tested the water again and all seemed ok except the pH (it was at 7.8). I purchased a pH up additive and dumped both bags in as instructed.

Monday morning did another test and pH was still at 7.8. Monday evening after i got home from work, i added more pH up. Tested the water an hour later and pH was around 8.0 - 8.2.

I then proceeded to add my remaining LR and fish to the tank. I fed them and they all seamed to eat and be happy.

This morning (Tuesday) they all are dead. Im so sad.

I did a water test and here are my results.
pH 7.8 Ammonia 0.5 Nitrite 0 Nitrate 0

I know some of that is bad but what killed all my fish and snails.

Please grill me on what i did wrong so i (or anyone else) won't make this mistake again.

Roger
 
Hey Marvin,
That really sucks, I'm sorry.

The fact that your pH was low suggests that there was something amiss. In other words, it was likely to be a symptom rather than a problem in and of itself. Artificial seawater is buffered to stay at about 8.2. The pH will be low for one of two reasons, that are not mutually exclusive.

First, excess CO2 is converted to carbonic acid, and will drop the pH. If there is a lot of biological activity (fish, bacteria, etc) then the CO2 produced will drop the pH. It can also be a sign of inadequate circulation, so that CO2 is staying in the tank and O2 is not getting in. This can be tested by taking a sample of your ASW and aerating vigorously for 30 min. If the pH goes up, then CO2 is probably your culprit. Also, your alkalinity will probably be near normal under this condition. If the problem was inadequate circulation, your livestock may have died from hypoxia.

Another source of low pH is organic acids, breakdown products from food, feces etc. Possibly stirred up when the CC came out. You should be able to determine this by looking at the alkalinity. The acids will neutralize your buffers, reducing the alkalinity to a low level. This shouldn't kill your fish overnight, though.

Another possible culprit would be a pH swing. You added a product that raised the pH, and then added the fish. The pH has clearly dropped since then, and the fish may not have been able to deal with that.

You also have ammonia, suggesting the tank was cycling again, but it shouldn't have been enough to kill the fish.

All that is speculation, and it may be "none of the above."
 
Well, as far as circulation, i think i should have plenty. The fluval canister was running over a day ago.

As far as left over food, feces, etc., there wasn't any cuz all i had was DSB from HD and LR (no life really, just some coralline algae).

Being a newbie, i would have to go with your third guess. The pH swing probably did them in.

My next question is has to do with the HD sand. If i was to add HD sand and salt water from LFS, would the sand cause a low pH?

Also, I removed all my fishes expect the goby. I can't find him. I do not want to give up on the hobby cuz i like the fish so much, and it is relaxing (when things are good). Will my tank go through a cycle with the dead goby in there? Im going to start slow now and try and learn from my mistakes.
 
Question,

You have a fluval on the tank. What do you have inside the fluval for filtration? Did you have the fluval off for a period of time with filter media in the filter when you were changing things over? If so how long?
 
I don't know really, I put what ever came with it. My brother helped me get into this hobby and set it up for me. He is by no way an expert, just knew more than me at the time.

I was just about to take the fluval out and wash out the media. I probably should have done it before putting the fish back in. It also has been set up since mid december. (wow seemed much longer than that, time flies when you starting at the tank every day).

Oh, and yes everything stayed in the fluval while i did the change. Im pretty depressed about what i did. (all my fish being dead now)

My next question is has to do with the HD sand. If i was to add HD sand and salt water from LFS, would the sand cause a low pH?
Click to expand...

so what do you think?

I am going to start over, but not after i learn what all my mistakes were.

Also, thank you all for your help. And Thank you Reefscape for such a wonderful site.
 
The sand won't reduce the pH--while silica will break down at extremely low pH (less than 3, at which you have a glass box of acid), it doesn't alter the pH of the water. I have silica play sand in several tanks, and the pH is stable in all of them.

However--if the fluval sat for a length of time with no water movement, and then was turned on, it could have gone septic--all the bacteria dead, the oxygen depleted, and then flushed that into the tank. This could have been enough to deplete the buffer, I think.
 
However--if the fluval sat for a length of time with no water movement, and then was turned on, it could have gone septic--all the bacteria dead, the oxygen depleted, and then flushed that into the tank. This could have been enough to deplete the buffer, I think.
Click to expand...
Sounds like a good theory.

Marvin, what is the alkalinity right now? I think it would be very informative.

If I understand correctly, you have cured live rock in the tank right now. It may not have to cycle again, although the sand will take a while to come to life.
 
im sorry, how do i check alkalinity?
Click to expand...
The kits are cheap and easy to use. Ask at your LFS. Get one, like the Aquarium Systems kit, that gives numbers. In my opinion, it's one of the best measures of your water quality.
 
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