Oxygen Starved

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anubis63

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Apr 11, 2015
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Robert Mortenson
Ok, I'll start off by saying that I have raised fish off and on for 20 years primarily Discus but I am really stumped with this one. Right now I have a 100 gal. aquarium 4 young Discus, about 3 1/2 inches two small plecos. two Cory Catfish and and one Black Knife. The ammonia is is 0, Nitrites 0, Nitrates 10, ph 7.0. The only thing I'm doing now that is new is having a planted aquarium with about 10-12 plants. I also have two canister filters one up to 150 gal. one up to 75 gal. and a hanging filter up to 100 gal. I run s do2 system, pressurized lots of water movement ther is no reason to have low oxygen levels in this tank as far as I can see yet all of the fish show signs of Oxygen starvation. When I first saw this I stopped the co2 and whatever might use up oxygen even after that they still act like that. My Discus in the past have always thrived in the aquarium but I am really really stumped at this one and it's driving me crazy. What the is going on I really need help with this one. I think I covered everything. Can anyone help me on this? :(
 
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SnakeIce

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CO2 and Oxygen levels are independent of each other, and although CO2 can get high enough to nuke things that doesn't sound like what happened.

Because of the various acids and bases, and the effects your buffering kh has on the tank ph readings are a sum of those. Because of the complexity the best way to know tank CO2 levels is to take a sample of your tank water and let it gas out to ambient co2 levels and take a reading of the current baseline ph of your tank. Whatever the difference between this and your tank is the amount your co2 additions are changing it. One log ph difference is about 30 ppm co2 concentration.

Generally there is enough Oxygen in the water if you have circulation that moves across the surface, it doesn't have to bubble or splash, just move across.
 

anubis63

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Apr 11, 2015
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Robert Mortenson
First off I'll give The Zigman the readings. They are showing more signs of stress except my most dominate one and he even takes a big open mouth breath every once in a while the others hang at the top by the canister filters spray bar, scratching, one darker in color even the Black Knife only comes out now a very few times and usually will go to the corner up at the top of the water and spray bar. Plecos jump to the top to tack a quick breath. To monitor the co2 levels I just use a co2 checker it's readings are in the correct range ant the water temp. is 83 degrees. The Kh is hard to read but it seems a little high but there are no ph swings and it stays around 7.0 and like I said there should be no reason for this behavior but I must be missing something remember I am only new to co2 injections and live plants the fish for many years. Yes SnakeIce your correct I hope my co2 checker is sufficient. Buy the way all thanks for your help I hope I gave you enough info to help to understand this.
 

FreshyFresh

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What water parameter test kit are you using? Are the plants the only recent addition?
 

SnakeIce

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Just curious, what light/s do you have on the tank (wattage and type of lamp/s)? Also what kinds of plants did you get? Plants do use a small amount of oxygen when the lights are out, but that usually isn't enough to cause problems if they are producing during the photo period. But that assumes they are getting enough light, and "enough light" can vary between kinds of plants.

I know you have a checker for your CO2, but you can check the checker by doing the comparison of the ph of your tank and of a tank water sample set in an open container on the counter for half a day. The difference in ph between the two would be just what is caused by the CO2. If your tank is running ph 7.0 and you had the target level of 30 ppm CO2 in the tank you could expect the sample ph to be 8.0 . If your CO2 checker runs things lower than that or even for some odd reason higher it would be good to know.
 

wesleydnunder

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Dec 11, 2005
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I'm leaning toward excess co2 at this point. You should test your baseline and saturation levels as SnakeIce suggested. I've kept discus in co2-injected tanks and they are not very tolerant of co2 getting too high.

Mark
 
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