# What could cause a tank to crash in a matter of hours?



## Jonney_boy (Apr 28, 2010)

My Discus tank crashed the other day and i can't for figure out what I could be. Maybe somebody here can see what i'm overlooking. (warning.. LONG post).

Tank is a 100 gal setup, 11 discus and a bunch of small dither fish (rasporas, bristle nose, cory's etc). I've had these discus for about 1.5 years now. All discus from one source (Forest).
Planted tank, co2 injected, two xp3 + 2236 as filters, ADA substrate, EI dosed, 4x t5ho.
Regular water changes is 50% every 2-3 days... I was on the 3rd day this time. Tank at 85 deg.

People are up late at my house, so the light schedual is set for really late hours. Anyhow, checked the fish in the morning at about 9am and they looked fine, still sleeping. As I would be out for most of the day, I dropped a little bit of blood worms + flakes in the tanke at 10am. Fish where still sleeping but I saw them wake up and start eating slowly. Called it good and left for the day.

3-4pm Parents noticed that one of the discus got spooked and "jumped". Hit the egg crate i'm using the cover the tank with and turned dark. It had a scratch on it's forehead + above the eye area.

I got home at 9pm... everybody in the tank look like they where about dead. Couple discus where belly up under a leaf, One was gasping at the top, and a few where hiding in the back. Also noticed the drop checker had been knocked off.

At this point, I took a bottle water for testing later and starting w/c like nuts. Did 70% 3 times.. and once more that night. I've been doing 50% once or twice a day since. All the filters where cleaned out that night "just to be sure".. they didn't look that bad tho. Once I started the water change the "upside down" discus flipped back over and hid in the corner.

So far, I've lost a few raspora's (which where getting really old) and one discus. The rest seems to be eating but a bit slow to respond. I don't notice any clamped fins but they are still a bit skittish. Lights have been turned down 50% and co2 shut off. The tank is also being areated as much as I can.


Water Tests done 3-4 hours later (on the water sample I took before the huge water change) looks ok.
Ammonium at 0,
nitril at 0
Nitrates at 5ppm
Ph 6.2-6.4

As for the drop checker.. I might have lost half the fluid?....... could that be it?


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## JohnnyAppleSnail (May 30, 2010)

My first guess was the co2 injection too much co2,I wouldn't have cleaned all the Filters but kept at least one dirty,with the co2 off you'll probably notice difference for the better,you should make sure when turning back on co2 that everything is up to check.


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## 2wheelsx2 (Apr 21, 2010)

I don't see that you did anything wrong. The one area that I might change is not to feed when no one is home to watch, ie don't feed just before you leave. Feeding means increased metabolism and waste production, and that coupled with the injured fish, may have caused the other fish to get spooked and release hormones and shed slime coat. I've seen this in my tank when one goes off and then the rest go off. I think you did the right thing with the increased water changes.


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## BCAquaria (Apr 24, 2010)

I've had a few BIG crashes. One due to a faulty heater that stayed on and didn't turn off. Which basically over heated the fish. 2nd was the co2 went nuts and basically suffocated them. 3rd was filter pad was too clogged and basically didn't filter properly while I was away for a week.

Only thing I could think in your case is maybe the co2 went haywire or maybe there was some sort of chemical poisoning (aka hand soap, etc).


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## April (Apr 21, 2010)

Sorry to hear...
Add salt if you can and some buffer. Bullseye or equilibrium or something to keep it stable. Otherwise even with wcs it will keep cashing.
Hope the rest are ok. I think the ph on Vancouver slid the last week or so. Another discus person I know had the same thing and my fish got a tiny bit shy for a day. Soon as I see my discus shy away I always do a large wc and add buffer right away.


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## Jonney_boy (Apr 28, 2010)

Well, quick update.... seems like the fish are doing better.. everybody is eating and the colour is getting better. With the co2 turned off, the fish seems more active. Plants on the other hand.... they have stopped growing and BBA is starting to set in... no biggie. this can be fixed later 


I'm still keeping up with the 50% water change once per night. EI dosing has stopped and I do dose a bit of equilibrium per water change (about a table spoon worth + a bag of aragonite in one of the filters). Fingers crossed.. I think they will be ok 

April, I considered adding some salt but have cory's and bristle noses in this tank. I'm not sure if they will take well to it. Granted a table spoon or two prob won't hurt much in a 100gal.


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## 2wheelsx2 (Apr 21, 2010)

The bristlenoses and cories will be fine as long as the salt dosing is reasonable. Don't add too much equilibrium if you're not injected CO2. It has a lot of K in it...maybe too much. Why don't you shorten and reduce the lighting for now, if possible, then at least you can hold the algae at bay.


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## mcrocker (May 29, 2010)

I'm no expert on CO2 injected tanks but like a previous poster the CO2 injection is the first thought of for causing sudden crashes. I've heard of some types of regulators 'dumping' when the cylinder gets get below a certain pressure.(when the tank is near empty, they give a flood of CO2) How full is yours?

Other than that for rapid changes I would think temperature, maybe a heater with a stuck thermostat. Could that be a possibility? Did you check temperature?


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## Jonney_boy (Apr 28, 2010)

AH, i'll cut back on the equilibrium a bit... and start dosing a bit of salt instead. As for the lighting, I have dropped down to a pair of t5ho's instead of 4. I can shorten the time a bit too.

Temps in the tank was fine. I stuck my hand in the tank for the w/c and it was normal. Co2 might had been a bit high but I have another 75 running on the same co2 regulator/tank and that tank has no problems. Yes I did check today and the co2 canister is a bit low (pressure has just started to drop).. I"ll re-fill it next week


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## 2wheelsx2 (Apr 21, 2010)

You can also replace some of the Equilibrium with just Epsom salts to up the Mg component and reduce the K component to buffer your GH.

As for the CO2, you can increase the surface agitation at the cost of some lost CO2 and just go back to your old rate of injection and lighting, or staggering the pairs of T5HO and keep the reduced lighting. I've found though that it's pretty tough to grow the more demanding plants with just 2x24w T5HO in my tank which is 24" tall, but I'm not injecting CO2.'

It's good that things are looking normal again. Keep up the water changes and maybe your discus will reward you like my Heckel and Cuipea X did, with some wrigglers....


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## 2wheelsx2 (Apr 21, 2010)

mcrocker said:


> I'm no expert on CO2 injected tanks but like a previous poster the CO2 injection is the first thought of for causing sudden crashes. I've heard of some types of regulators 'dumping' when the cylinder gets get below a certain pressure.(when the tank is near empty, they give a flood of CO2) How full is yours?


Single stage regulators will _sometimes_ allow a EOT dump as I've had it happen. Won't happen if it's dual stage and also not if the pressure is above 200 PSI in general.


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## discuspaul (Jul 2, 2010)

Interesting thread, along with helpful posts. Good job, folks.


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