aquarium crashed....or why you should never do late night water changes

[nick_76]

so over the weekend i didnt manage to do a water change and toss in some meds for my fish till rather late at night, normally i do so earlier in the evening...
the next morning i wake up and from my room i can see out to my tank, and my discus are generally clustered on the side facing me...this time-nothing...i walk out, thinking "hmm..this is odd" ale: look in the tank, see no fish at at (at first), then i notice all my smaller fish gasping at the surface, and 4 of my 5 discus laying dead on the bottom...the fifth one (who i was treating cuz he hasnt eaten in about 3 weeks) is propped up against the tank, gasping, completely white...

what a gut wrenching feeling :no: ...and when i came back to work today, whats my desktop background? a group shot of all my discus

if i had dont the water change at a decent hour, i wouldve caught the problem before it became lethal. instead, my tank became a death chamber while i snoozed nearby

i have a dual cannister setup, and the one that primarily agitates the surface...wasnt. its output was a shadow of its normal self. the other one uses a power head rather than a spray bar. normally the venturi isnt needed, this time it wouldve been a life saver if it hadnt have dropped into the water

i immediately disconnected the filter from the powerhead to give it a no-load flow and opened up the venturi all the way, changed out 50% of my tanks water in case the dead fish spiked the tank with ammonia...even still it took the blue discus about 5 hours to regain its coloring, and another 4 or 5 before it could swim. it still doesnt look fully recovered and has no interest in food

life sux

 

[JimA]

Seems like something other than a crash?

 

[nick_76]

well, yea it was a mechanical failure...and my mistake for not doing this in a timely manner so i could monitor for issues...

but as far as im concerned, its the same thing...same end result

 

[flo77]

I am sorry for your loss. I am 99% sure that the cause of the death is the lack of oxygen. In a planted tank during the night the plants also use the oyigen and give up carbon dioxide. Add the malfunction of your equipment and the number of fish in your tank, the higher water temperature in a discus tank and you can have a picture of what happened. It happened to me also(the air tubing and the airstone came to the surface and the water was depleted of oxygen during the night) . I managed to limit the proportion of the disaster by using the airstone and giving oxygen to all the discus which were still alive. Since then I have an air pump and a power head with a venturi in that tank.

 

[nick_76]

yea, it was oxygen depletion. like i mentioned i was barely getting any flow out of my spray bar so there was no surface agitation at all...

i really wish there was a low oxygen alarm or something to warn me...not sure what to do to make sure this doesnt happen again...but id rather not use the venturi on my power head full time...

 

[flo77]

If you plan to buy other discus you have to do something for the aeration during night time. You can use a timer. It's a good thing to have a redundant system(2 air pumps, one air pump and a power head etc) in case that one fail. Right now I am using an air pump and the power head in my 75 gal planted discus tank.

 

[nick_76]

pump on a timer...now why didnt i think of that?!

 

[Anonymous]

Since my fiancee's tank got too hot last summer and we lost a bunch of stock, I always have a bubbler in big tank, and she's added a power-head aimed at the surface.
I use one of the big one's with 2 out puts & a dial to adjust flow. Split 'em together, and anytime the noise bothers me, turn it down. Then, at some point in the future, I'm like "WTF happened to my bubbles?" and turn it back up. ^__^

 

[nick_76]

my power head is set up to pull water through a filter and sterilizer on its suction side (its a german filter so rather than replace the motor, i pulled the impeller and hooked it up to a power head) and i just dont like the venturi shooting large clouds of bubbles directly at the front of the tank...in fact a bubble free tank is pretty much ideal as far as im concerned...

i really like tunze power heads, but even the smallest would set up a current i dont think the discus would appreciate, but they sure can set up some surface agitation.... i think im gonna go with an air pump on a timer though...i can even set that to go on and off periodically throughout the day in case something happens while im at work(i dont want it running continuously through the day as itll dissipate the co2 im pumping into the tank during the day)

by the way...i used to have a battery powered air pump years ago, in case of a power outage...but i never see them available anymore...has anyone else seen these locally, or should i resort to online?

 

[flo77]

Assuming that you don't inject too much CO2 you would need air pump only while the lights are off.
Now that you mention the CO2 I can see another cause of your fish death: after you changed the water you might increased the KH of the water. If you control the CO2 with your new pH controller keeping the pH constant means more CO2 for an increased alkalinity. Add to the lack of oxygen, higher temperature(the DO is lower with increasing temp),plants adding CO2 instead of oxygen...you got the picture.

 

[nick_76]

my ph stays stable during the day at 6.5, during the night i see a .12 drop- when i wake up its 6.38 most mornings

when i make new water for the tank, i use discus buffer by seachem i think- generally after a water change im looking at 6.44 average

bubble counter is set at about 1/per second or so

temp was about 88...i was dosing with tetra parasite guard and salt (1 teaspoon per 10 gal)

 

[Nick_87]

The higher the temperature of your water the less oxygen remains disolved for the fish to breathe with in the water too so raising your temp to cure and infection or parisite could have added to the problem along with going without a water change.

 

[flo77]

Have a look at pH/kH/CO2 chart.
http://freshwater-aquarium-passion.blogspot.com/2010/07/phkhco2-relationship.html
Let's say you control the pH at 6.6. If your alkalinity is 3 the concentration of CO2 is 22mg/l which is safe for fish. If after a water change your alkalinity increases to 4 your pH will drop so the controlerl will allow more CO2 until you reach your setpoint of 6.6. Then the value of CO2 concentration will be 30 mg/l which is no more safe. This is a possible scenario which could make worse the malfunction of the equipment and the depletion of oxygen.
Note: An uncalibrated/improper calibrated probe/controller may give a wrong indication of the pH.

 

[nick_76]

i have a new probe and calibrated it in ph 4 & 7 solutions.

installed an air pump on a timer last night, slept more soundly

just out of curiosity, how much of a daily variation in ph is safe, and at what point should i be worried?

the remaining discus still shares no interest in food....ive seen bloodworms, which were like crack to its old tankmates, land on its head without it noticing. likewise with blackworms, hikari discus gold, marineland flakes....id hate that this fish recovered from near death like it did only to continue starving itself...but im not ready to restart its med regimen again for a little while till im sure its strength is regained from the weekends ordeal. 3 days on parasite guard yielded nothing

 

[Anthraxx]

id suggest you look into some information written by jack wattley. he really knows his stuff and can probably point you in the right direction. GL to ya discus can be tough.