Post
by Diana » Fri Sep 21, 2012 2:00 am
I am wondering if this tank has a condition called Old Tank Syndrome.
Description:
A tank goes along, perhaps for years, not getting the water changes it needs to remove the organic waste. Too small, too infrequent water changes allow the waste (fallen food, fish poop, fallen leaves, dead plant parts such as roots in the substrate...)
But the microbial colonies are strong, there are enough minerals and oxygen for them to thrive, and there is plenty of food. As they grow, and keep on decomposing the waste they start using up the minerals, especially carbonates.
Carbonates stabilize the pH.
The lowering level of carbonates allows the pH to drop. The fish adapt to the reduced minerals, and the pH changes are not a problem.
Then the microbial colony fails, or at least takes a catastrophic dive. The minerals are almost gone, the pH is dropping out of their preferred range. The beneficial bacteria, fungi and so on are no longer doing their job. From here on I am going to concentrate on the nitrifying bacteria. They specifically must have carbonates to live. They use the carbonates as their source of carbon. They cannot use the carbohydrates that are all around them in the fallen food, fish poop, fallen leaves and so on.
Suddenly you notice that the ammonia is rising. If you check the pH you find it has crashed.
But! At that low level the ammonia is actually in the form of ammonium, and not so toxic. So you do a water change. This brings the pH up some, and some of the ammonium in the tank, either remaining after the water change, or freshly produced by the fish becomes ammonia.
Toxic.
Fish are dying.
The rise in ammonia came first (in the form of ammonium). This is the ammonia that the bacteria has been handling all along. The dying fish add more ammonia to the system.
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Why to follow the next instructions:
If the pH rises too fast, before the ammonia is under control, the ammonia becomes toxic to the fish.
But the bacteria needed to control the ammonia cannot thrive under conditions of very low pH.
Catch 22.
A sudden change in mineral levels in the water is dangerous to the fish.
So we will do these changes slowly.
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1) Small water changes, 10% every day for a week. It is not much, but it will start adding a small amount of carbonates to the water. Emphasize vacuuming the floor of the tank, getting under all the rocks and driftwood. You will not be able to vacuum the whole tank in one go, but each day do perhaps 1/4 of it. Use a double dose of dechlor. Do not use any other minerals, bacterial additives or anything else. Most especially do not use any pH altering materials. Clean one of the filters this week. Get the Seachem ammonia test. It is specifically designed to show you ammonium vs. ammonia, and works with Prime to give you accurate results. I think the 'hang in the tank' constant ammonia test has the same technology, but it is slow to respond.
Test and record the results for:
Ammonia
Nitrite
Nitrate
GH
KH
pH
TDS if you have a meter.
Buy or order a bacterial additive that includes Nitrospira. Do not waste money on anything else. These are the actual species of nitrifying bacteria that you need to have to remove ammonia. They will not grow well in water with such low carbonates, so I would not add them, yet. You could, if you wanted to, but I wouldn't. I am telling you to buy this now in case you have to order it. Make sure it is shipped fast, and will probably include a cold pack. It must not be not frozen, just cool. If you go buy it on a hot day hurry it home, just like fish.
Feed the fish more plant based foods such as fresh or lightly cooked vegetables. If you have carnivores they will have to be fed high protein foods, but feed them as little as possible as long as they are not eyeing their tank mates as dinner. Protein in the food is broken down by whatever microorganisms are left and becomes ammonia. Plants are much lower in protein, so if the fish will eat them, feed them as close to a vegetarian diet as possible.
If there are not already plants in this tank I would add plants, and make sure the light is good enough to keep them growing. Plants are a superb nitrogen sink, taking in ammonia, nitrite and nitrate as long as they are growing. Something simple like Anacharis would do double duty: The fish can eat it if they want. For your large a tank this will mean a lot of plants, though.
By the end of one week you will have greatly reduced the amount of debris in the tank, and added a small amount of carbonates to the system. Any microorganisms that have survived so far are now incorporating those carbonates in their cells and beginning some recovery. You are probably not seeing any great reduction in the ammonia, but hopefully it is at least stable, and in the form of ammonium, not ammonia. The pH should still be low. The GH and KH should be slowly rising, but not much. If nitrite shows up use 1 teaspoon of salt per 20 gallons. When you do water changes add just that much salt to the new water. A 30 gallon water change gets 1.5 teaspoons of salt.
2) Increase the size of the water changes. 20%, every day for a week. Keep on rotating through the tank deep vacuuming as much as possible. Clean the other filter this week. These water changes will be adding more carbonates for the bacteria, and is a big enough water change to remove a bit more of the ammonia. Still use a double dose of dechlor. The pH should start rising a bit. The microorganisms are recovering, but slowly.
Continue monitoring the water parameters, and same comment about nitrite.
As soon as the KH holds steady at 3 German degrees or a bit higher add the bacterial additive you bought last week. Note that most of these packages say do not do water changes for at least a day after using the product. Follow label directions.
3) Increase the size of the water changes. 30%, every day for a week. Clean your third filter this week (Very gently- the new bacteria are barely getting well stuck). Similar to last week, these water changes are adding carbonates, but these water changes should be seriously affecting the water parameters. The ammonia should be getting significantly lower. I hope the pH is staying low enough (mid 6s) to keep more of the ammonia in the form of ammonium, but I also want the pH to be climbing slowly. The water in the tank will be a lot more like the tap water for GH and KH. This ought to be helping out the microorganisms a lot. You could add another bottle of Nitrospira (you have a big tank) if the bacteria are not getting going so fast.
4) From here on out it is more of a matter of watching the water parameters. You will probably start backing off the water changes. (See comment under ammonia and nitrite in the next paragraph) The bottled bacteria ought to be really kicking in now, so the ammonia ought to be gone, and any nitrite is a low, brief spike, then gone. The tank water should match the tap water, so larger water changes will not cause problems for the fish. Go back to the regular diet of the fish, but remember: Many people are over feeding their fish. You might try feeding 50% or maybe 75% of what you used to feed, and skipping feeding at least one day per week.
Here are the possible test results and what to do:
Ammonia: If it is zero, cheer! If there is any lingering hint of color on the tests then keep on using the larger dose of dechlor, and keep on doing water changes.
Nitrite: Sometimes the bacteria that remove nitrite are slower growing, especially under sub-prime conditions. Maintain the salt at 1 teaspoon per 20 gallons. If the Nitrite is zero, then quit adding salt to the new water. Allow regular water changes to lower the salt level in the tank.
If either ammonia or nitrite show on the tests, these will dictate the water changes:
Do enough water changes to keep the ammonia under .25 ppm and the nitrite under 1 ppm. Dose dechlor as needed (per label directions) for ammonia or nitrite in addition to the chlorine or chloramines in the tap water.
Nitrate: As the bacteria make a good recovery the nitrate will start really rising. As it does, do enough water changes to keep the nitrate under 20 ppm. Monitor this regularly, and set up a water changes schedule (frequency and volume) that will keep it under 20 ppm. This may be something like once or twice a week about 30% water change.
GH: Optimum value for soft water fish is under 9 German degrees of hardness, but many will handle it a bit higher. Minimum would be 3 German degrees of hardness. You will be doing so many water changes that this should match the tap water. The fish use some of the calcium, but water changes ought to replace it.
KH: This is carbonates, needed by the nitrifying bacteria. Also, the major buffer that stabilizes the pH. Like GH, you are doing so many water changes it should match the tap water. It should be roughly the same as the GH, but probably won't be exactly the same.
If there is any reason to alter the tap water to increase or decrease the GH or KH, let me know, and I will see what should be done.
pH: The actual pH is not so critical, but watch it! It is often the first thing that starts to vary when things are starting to go wrong with the tank. Soft water fish tend to prefer pH that is somewhat acidic to neutral, and most are just fine up to about 7.5. The nitrifying bacteria thrive in more alkaline water, higher pH, so start worrying if the pH remains too low. Check the KH as soon as you see a problem with the pH.
TDS: This is a test of all the stuff dissolved in the water. It seems to be more often used in planted tanks (perhaps because of the fertilizers), but can also be useful in non-planted tanks. It should be stable. It should not rise or fall through the week.
GH, KH, pH and TDS: Keep a record, and test the tap water occasionally. If any of these start to vary in the tank, immediately test the tap water to see if that was the cause, but also test ammonia and nitrite.
All the tests:
Some are important that the actual value really be optimum, or at least within a range. Some tests are not so critical what that number is, so long as it is stable.
Ammonia: Optimum = zero. Acceptable range: No acceptable range. If it is not zero there are problems.
Nitrite: Optimum = zero. Acceptable range: No acceptable range. If it is not zero there are problems.
Nitrate: zero to 20 is a good range. Many fish will handle higher nitrates, but I think that other things (that we do not measure for) are building up if the nitrates keep rising. 20 ppm is plenty high enough to suggest that the other things are also getting up there, too. Do water changes.
GH: 3 to 9 degrees is a very general range for most soft water fish. Research the fish you have (or will buy) for their GH requirements.
KH: 3 to 9 degrees will usually keep the pH in the right range for fish and bacteria, and makes sure the bacteria have the carbonates they need. If the KH is too high the pH will usually be too high. Post this information and lets see what can be done.
pH: This is the one that is most often thought of as so important. It is not. It used to be, but now we know GH and TDS are probably the most important. pH is just another test that can be used to see that conditions are stable. I would hope that it is somewhere between 6.5-7.5. Lower is not good for the bacteria, higher is not so good for most soft water fish, but pH is not as important as the other tests. If it is higher, do not worry as long as it is stable.
TDS: This one is quite important, but like pH it is not that a specific number is right, just that it is stable. If you need to make water changes that are really big, make sure the new water has the same TDS as the old.
38 tanks, 2 ponds over 4000 liters of water to keep clean and fresh.
Happy fish keeping!