Once you begin to take care of fish and you have an aquarium. There can be preventative maintenance you are unaware of in the beginning. Aquariums that have been in use for extended periods will face issues, and if not tended to, it can lead to dirty water and unexpected dead fish.
New tanks can face a condition aquarium owners may not be aware of immediately. Every fish owner should know about NTS or new tank syndrome. We all know that fish poop, and some more than others do. Fish filters can struggle to cope, you may face algae growth, but there are other things; tank owners may not know.
Newer tank owners look at all this and think that water conditions are the only thing they need to deal with. This leaves them in a vulnerable position where they face OTS. OTS (Old Tank Syndrome) is open to discussion of when it occurs. It can happen much quicker than you think, and the effects can take their toll on new fish.
Fish that are purchased and added to a tank can suffer almost immediately, and owners of aquariums may think they have bought sick fish. This is rarely the case and it is OTS, which causes the issues.
This issue can stem from the substrate in use and leads some tank owners to ask.
Does aquarium gravel go bad? The gravel itself doesn’t go bad; it is the conditions in the tank if there is insufficient cleaning. While there may be water changes, these don’t account for all the wasted food and poop which fills the small spaces in between gravel. Ammonia and nitrite levels increase and thus lead to issues with your fish.
Gravel cleaning takes some specific processes to do it right without affecting all the good bacteria in your tank. Read on to learn how OTS happens and what you can do to eliminate it and make sure your gravel is as clean as possible.
Prevention is the Best Form of Cure for Aquariums
You can easily test all the required parameters that keep your tank in tip-top condition. These can be done cheaply using inexpensive equipment.
- Dip strips
- Liquid kits
- Water testing kits
These are just some, and there are many more available, so tank owners have no excuse. One of the worst things to accumulate in an aquarium is Nitrates. New tank owners can often be under the belief that they only have to test at the beginning of cycling their tank.
In reality, you need to do these tests weekly. OTS can creep up unexpectedly because a tank owner does need to keep on top of the Nitrate, pH and phosphate levels among others. All these readings are reliable indicators of the health of your tank conditions.
Testing can be straightforward, yet the prevention can be harder to accomplish.
What is the Best Prevention of Old Tank Syndrome?
Tank maintenance, water changes, and above all, gravel cleaning, are the best ways you can prevent the above issues.
OTS happens when tanks face neglect, and this can be the space of a week and not for extended periods. No matter who says they can tell the condition of their water from its appearance, they are wrong.
In many cases, water changes do solve many issues. By doing this, you dilute the nitrate levels and the levels of phosphates. Additionally, doing so will add more minerals and helps to boost hardness. This raises the KH, GH, and pH.
Here are a couple of examples when water changes need to be done:
Bad condition: Several smaller water changes because one won’t be sufficient. Change 25% of the water on alternate days until levels are stable.
Extreme conditions: Once you reach this, it will require some drastic action. It can be necessary to carry out a 50-75% change in water. You can also add a re-mineral tropic; this can help to boost KH and GH levels. If you have a high level of ammonia in your tank, then you can treat this with a good quality ammonia detoxifier.
While you can tackle all these issues at once, the results can be short-lived. There is the aspect of all the hidden waste, which hides inside your gravel.
Why is the Waste in Gravel So Bad?
Cleaning your gravel can be one of the best and most effective ways in the prevention of OTS. Here, you can see how other factors can help in the formation of OTS, yet many of them still relate to the condition of your gravel.
Inadequate water changes.
- Overstocked levels of fish
- Uneaten food
- Filters not cleaned regularly
- Dead fish, shrimps or snails
- Decaying aquarium plant matter
All these will have an impact on the conditions of your gravel. One of the most significant being all this hidden waste will eat up all the carbonates. What this does, and won’t be apparent is the increase in Nitrate release.
If you don’t attend to this, you can face hydrogen sulfide production. Once this happens, there is a severe drop in oxygen levels in the gravel, and all the wrong types of bacteria begin to thrive.
Filters can get rid of a portion of this, yet if they become blocked, or the production of these bad bacteria is too high, then filters won’t cope, and the problem escalates.
Aquarium Gravel and How to Clean It
No matter which kind of gravel you use, you should aim for around 2 inches in depth. However, there are differences when it comes to living plants. Finer gravel can allow you to insert live plants, and they will have a stable environment. Larger gravel won’t support live plants, and more waste and food will fall between the larger gaps.
On the other side, the smaller gravel compacts more, and in different areas of the aquarium, there can be a lack of oxygen because of this.
What every aquarium owners have to know in the fight to prevent OTS is how often they need to clean their gravel, and how they go about this.
New Gravel: If you are beginning a new tank and using gravel, then this will need some prior cleaning. The best way to do this is to rinse your gravel in warm to hot water. You do this until all the dust and debris washes away and the water runs clear.
Some tank owners leave some of the gravel in a separate jar for a couple of days to see if it changes the pH levels. Most gravel won’t, yet it is one more step to eliminate issues.
Cleaning Aquarium Gravel: There are some occasionswhen tank owners may clean the entire contents of their aquarium. They can clean the gravel in the same way as above before moving back into the tank ready to fill again.
However, when the tank isn’t being emptied, the gravel will require cleaning no more than once per week. These times can be extended depending on the number of fish, and how much poop and uneaten food there is. It may be possible to see some biological waste on smaller gravel, yet it may be out of sight in larger gravel.
The way to clean your gravel in this instance is to use a gravel vacuum. Once you use these, you need to resist the urge to go around your tank.
The recommended amount of cleaning is between 30-40% of the gravel, and as you can see, this is the same recommendation when carrying out water changes.
How to use an aquarium vacuum:
- Place a bucket next to your aquarium. You do need to place this lower than your tank.
- Place the vacuum (siphon) toward the bottom of your tank, and allow it to fill with water.
- Place your finger over one end of the siphon, and lift this end from the tank. Hold this up, and the air should escape.
- Release your finger from the end that is by the empty bucket, and the water will begin running from the pipe. This causes the “vacuum” effect.
- Move the head of the vacuum along and into the gravel. You can see gravel lifting along with the dirt. Many of these gravel vacuums have built in filters to prevent gravel escaping.
- Carry on until you remove between 30-40% of the water from your tank. In most cases, this will be closer to thirty.
- Top off your aquarium with clean water (de-chlorinated and treated). Be sure to test pH levels once things settle.
Aquarium vacuums make cleaning the gravel a lot easier. OTS can happen to any aquarium enthusiast, and it isn’t because they do anything wrong. It is the way things go, but doing these regular gravel-cleaning exercises as part of your water change, and you can see you have a healthier tank, and you haven’t exerted any more effort.

Hi, my name is Adam and I’m an aquarium enthusiast! I didn’t discover the joys of being an ‘aquarium fanatic’ (as some of my friends call me!) until I was in my 20’s. When I first started out I found it difficult to find all the information I needed so I started this website to compile all the useful information I can think of. Enjoy!
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