Weird problem, low oxygen levels

[CatsMeowww]

Okay, so I have a 75 gal. with a HUGE amazon sword, a bunch of sag. and val. I know the tank is borderline overstocked at the moment with:
1 adult gold severum
1 juvie green severum
1 pictus catfish
2 gymnogeophagus (pair)

4 zebra danios (soon to be moved)
1 pearl gourami (soon to be moved)
2 bala sharks (soon to be moved)

The danios and gourami are getting moved to a separate tank within the next day or two, and the bala sharks are going to someone else. Is it okay to use an air pump in a planted tank? This morning I woke up to all of the fish hyperventilating, so I started the air, out of fear that they would die otherwise.

Once I move the extra fish, things should balance out, but I am still curious...is it that bad to use an aerator in a planted tank, at least when the lights are out, to increase oxygen levels? Or will this be a serious setback to the plants?

[bradlgt21]

From what I have heard from other members in here. Plants take in CO2 and give off oxygen only with lights on. But when lights are off they do the opposite. Usually people don't run into problems unless they are running there CO2 over night.

Is this the case do you have a CO2 system that runs 24/7? If so getting a selenoid with a timer so it goes off when lights go out would fix this problem.

If you aren't running CO2 then a weird problem indead but no it won't harm anything to run aeration with lights off. I have heard of many people doing it that run there co2 24/7. It won't hurt anything.

[Dangerdoll]

I usually run a powerhead in my planted tank which blows in air and it seems to work well for my 75g

[excuzzzeme]

You didn't mention the size of your fish so it is a bit difficult to guess if you truly have an O2 and not something else. You also didn't say if the added air helped?

An air pump indirectly causes more O2 in the water by increasing the amount of surface area exposed to the air. During this process it causes the water to off-gas the CO2 that plants take up as a part of their nourishment.

Running the pump won't hurt the plants, they just may not grow as fast as they might otherwise do.

[bradlgt21]

I was thinking the same thing and forgot to mention it. You should check your water levels. If you worried about overstocking then you might have overloaded your bio filters especially if you introduced a lot of fish at once. If you haven't already do a test for Ammonia, Nitrite, and Nitrate. Any ammonia, or nitrite would be bad and is the cause of the fish destress. Nitrate above 20 means clean the water and they should get better.

[jpappy789]

Were they gasping at the surface or was it just excessive gill movement? I would definitely check the NH3 and NO2 levels immediately. Too much ammonia and nitrite will hurt the gills. I'd say it's hard to run into O2 problems unless you have virtually no surface agitation or you're much more overstocked than you currently are.

[gagaliya]

This morning I woke up to all of the fish hyperventilating, so I started the air, out of fear that they would die otherwise.


define hyperventilating, are they at the SURFACE gasping for air, or do you mean rapid movement of the gills but not at the surface? did you check the water params.

also turning off co2 at night will not do anything other than save some co2, if you are low on oxygen you will still be low on oxygen. To increase oxygen buy a $10 small powerhead and stick it by the water surface, plug it into a coralife timer, so when the light is off powerhead comes on, when light is on powerhead goes off.

Check to make sure your problem is indeed lack of oxygen, usually people get way over worried about lack of oxygen in their tank. If you have a planted tank, chances are your oxygen is just fine. Just a tiny bit of surface movement is more than enough at night....

[Turbosaurus]

If you are not running CO2 on the tank, then there is some other problem. You didn't mention CO2 suplimentation, so I am going to assume you are not.
I would second the motion to check your water parameters (ammonia and nitrite specifically). I don't think its that you don't have enough oxygen in the water, I think that something may be interfereing with the fish's ability to absorb the O2 present- like gill inflamation from ammonia, or perhaps a bacteria bloom from a sudden increase in bioload. Even in a cycled tank, if you suddenly increase the ammount of ammonia present your bacteria colony can skyrocket and that bacterial bloom will use up a ton of O2

There is NO reason not to run an airstone in the tank unless you are injecting CO2. If you are not adding CO2, go ahead and run the airstone all you want, and always it was the right decision to add it if your fish are gasping. If you are running CO2, put the airstone on a timer to turn on when lights go out.

[CatsMeowww]

Thanks for all the input...I forgot to add that I do NOT currently use CO2 in the tank. I have been having a big algea problem that started around the same time as the O2 issue.

They were "gasping", but not all were near the surface. The pictus was definately swimming at a much higher level than usual, as were the gymnos. It appears they are much better with the air running. I had initially ruled out a problem w/ params. because they still had the problem the morning after a 50% water change, which usually improves the water.

I'll just keep the air running until I have the tank set up for the gourami and zebras...and keep a close eye on the params.

[jpappy789]

Do you have a test kit? If so you should check the ammonia and nitrite levels so you can completely rule out the possibility.

[bazil323]

I agree. This is usually a high ammonia/nitrite problem that causes this behavior. Also, what's your temp? Higher temps equals less oxygen in the water, so if you have a heater malfuntion or something that has the temp way up, that might contribute also. But, my bet is on the ammonia/nitrite because of the overstocking.

[CatsMeowww]

Yeah, I have a heater, but I checked the temp multiple times, and it is remaining as it has for the past year, at 78.

I do agree about the ammonia/nitrite, however when I tested, it also was consistant with past numbers. It's just plain weird. I hope that moving some of the fishies will help.

[jpappy789]

Past numbers = what? Ideally you shouldn't be showing ammonia or nitrite. Even levels that are not necessarily fatal could be irritating the gills. Also, what brand of test?

[CatsMeowww]

Well, I was using the strip tests, but in the last few days have had doubts based on the research I have done. Will probably be picking up an "actual" test kit this evening on the way home from work...I was planning to get the API freshwater?

[jpappy789]

Good idea.

[CatsMeowww]

Quick update: after work yesterday, I stopped by the LFS and picked up a liquid test-kit. I didn't do ALL of them, but the ammonia was 0, nitrates 0, and nitrites 0. Since the aerator has been running (turned it on yesterday, it's still going) the fish are all back to normal, with no signs of heavy breathing or other distress.

Does algae (I think it's hair, or beard algea) USE oxygen? I thought it functioned like other plants, using CO2...

[fabsroman]

Algae functions exactly like plants. However, that means it too will use oxygen at night.

How established is your tank? I had almost the same exact setup. 3 compact swords and a ton of corkscrew val and jungle val in my 75 gallon tank. I started out with just 10 of each plant, but they started multiplying like crazy. Eventually, I ran into a CO2 problem. The Vals can scavenge calcium carbonate from the water if there is not enough CO2, and mine had scavenged it all. The sword will suffer. Buy a calcium carbonate test kit to see what your level is and add baking soda if it is too low. You also have to realize that calcium carbonate acts as a buffer to help increase the CO2 level in the water.

The fact that you have 0 nitrate tells me that you have a lot of plants in that tank. I usually have 0 nitrate too in a well stocked tank, but I am now using pressurized CO2 and ferts for the plants. Otherwise, everything would be dead.

[CatsMeowww]

I have had the tank up for about a year and a half. It's pretty heavily planted, which is why I wasn't using an airstone for so long...never needed one. You're right about the sword...it has been deteriorating w/ holes in the leaves lately. I tried adding API root tabs, which appear to be starting to help, but I will try the calcium carbonate test you mentioned. I always thought the sword would scavange, not the vals.

How much baking soda should I use, if that is the problem?

[fabsroman]

I had my tank set up for a year before things started to go south. For me, the health of the plants went south pretty quick, but with a lot of reading done in a short time and a lot of ordering of Flourish products and a CO2 system, I was able to get everything healthy again.

This is the online kh calculator that I use:

http://www.dataguru.org/misc/aquarium/calKH.asp

[schaadrak]

Baking Soda is Sodium Bicarbonate, not Calcium Carbonate, and will temporarily spike your pH, which could cause more problems. Calcium carbonate is lime, dolomite, and mollusk shells. If your water is hard, then you should not have a problem with the vals pulling carbonates from the water as the carbonates will reform as CO2 levels increase and the pH dips back down. If your water is soft (GH is below 5), then you can raise the hardness by adding MgSO4 (Epsom Salts) and CaCl neither of which will alter the pH the same way that calcium carbonate can and its faster than CaCO3. To do this you:

#1 Measure starting GH of your aquarium water
#2 Prepare concentrated solutions of each chemical (MgSO4 and CaCl2)
#3 Add a small portion of Mg solution to the aquarium and measure resulting GH increase
#4 Add Mg solution until you get about what you want (I'd recommend a GH increase of about 1-2, no more)
#5 Then start adding the Ca solution until you get a GH increase that is 4X that of the increased GH due to Mg
#6 The final GH should be over 6, preferably around 8

Your low O2 levels are caused by your high bio-load, not CO2 levels. You could have very high CO2 and O2 levels simultaneously, but all of the life in your tank will deplete the O2 in no time without either aeration or an equally high photosynthesis rate.

Pinholes in leaves are a sign of Potassium (K) deficiency, not poor CO2 or levels. I would concentrate on dosing fertilizers first, then determine whether or not CO2 is necessary.

[jpappy789]

Baking Soda is Sodium Bicarbonate, not Calcium Carbonate, and will temporarily spike your pH, which could cause more problems. Calcium carbonate is lime, dolomite, and mollusk shells. If your water is hard, then you should not have a problem with the vals pulling carbonates from the water as the carbonates will reform as CO2 levels increase and the pH dips back down. If your water is soft (GH is below 5), then you can raise the hardness by adding MgSO4 (Epsom Salts) and CaCl neither of which will alter the pH the same way that calcium carbonate can and its faster than CaCO3. To do this you:

#1 Measure starting GH of your aquarium water
#2 Prepare concentrated solutions of each chemical (MgSO4 and CaCl2)
#3 Add a small portion of Mg solution to the aquarium and measure resulting GH increase
#4 Add Mg solution until you get about what you want (I'd recommend a GH increase of about 1-2, no more)
#5 Then start adding the Ca solution until you get a GH increase that is 4X that of the increased GH due to Mg
#6 The final GH should be over 6, preferably around 8

Your low O2 levels are caused by your high bio-load, not CO2 levels. You could have very high CO2 and O2 levels simultaneously, but all of the life in your tank will deplete the O2 in no time without either aeration or an equally high photosynthesis rate.

Pinholes in leaves are a sign of Potassium (K) deficiency, not poor CO2 or levels. I would concentrate on dosing fertilizers first, then determine whether or not CO2 is necessary.Nutrient deficiencies, as I have been told, are not always an A thus B situation. What I mean is that pinholes do not always point to a potassium problem. Other factors, such as CO2 or lighting, could be limiting the uptake of potassium. It's hard to say what exactly is causing the problem but I would agree that target dosing should be the first step in determining the cause of the problem.

[schaadrak]

Nutrient deficiencies, as I have been told, are not always an A thus B situation. What I mean is that pinholes do not always point to a potassium problem. Other factors, such as CO2 or lighting, could be limiting the uptake of potassium. It's hard to say what exactly is causing the problem but I would agree that target dosing should be the first step in determining the cause of the problem.
True, the nutrient deficiency might not be the underlying cause but rather a symptom of another problem. But if CO2 or lighting were the limiting factor, nitrates would probably be higher than 0. That does bring up the fact that exceedingly high levels of other anions (Ca, Mg, & ammonium in particular) will inhibit the uptake of K.

[CatsMeowww]

This is turning out to be more of a learning thread than I initially expected. I think I have been just going along for a few months with the status quo because it worked at the time.

So, I have begun dosing Excel, and added API root tabs to the substrate. I really don't want to go CO2, becuase I'm trying to keep as natural as possible, and I think the fish produce enough. The bio-load is now a little lighter, as I have moved the zebra danios and gourami into their own tank...I'm working on moving the Balas as well. I'm hoping to get to a truly South American biotope.

The current lighting is 6 15 watt CFL's for 12 hours each day, which comes out to 1.2 wpg. I think it's on the low side, but would that be causing the pinholes?

I'm also running the powerhead with an airhose attached at night.

[CatsMeowww]

If your water is hard, then you should not have a problem with the vals pulling carbonates from the water as the carbonates will reform as CO2 levels increase and the pH dips back down.

The water is on the hard side straight out of the tap, and when I test it a day or two later, it is only a little softer. Where would I find CaCl2 and CaCO3? Are epsom salts the same as aquarium salt?

Chaadrak, I see you're from Jacksonville -my husband grew up in Titusville and went to high school in Jacksonville.

[schaadrak]

Epsom salts are available at any pharmacy. Calcium chloride should be available at the hardware store with pool supplies, road salt, or concrete additives. Calcium carbonate is available almost anywhere as limestone rock, crushed coral, crushed oyster shells, dolomite and a few others. You could also purchase any of them online, too, they're not dangerous.

[CatsMeowww]

thanks! I'll check it out.