Red Eared Slider Tank Cleaning and Water Chemistry

Once you have your nitrogen cycle up and running, you’ll just need to do some regular maintenance to make sure that your water chemistry stays stable and your turtles have water that is within safe parameters. For this, you’ll need to keep using your test kit (remember, chemical liquid test not paper strip, strips are prone to inaccuracy!).


Safe Parameters for Water Chemistry

Ammonia: 0ppm

Nitrite: 0ppm

Nitrate: 20-40ppm

pH: 6-8



Ammonia: The natural byproduct of the decomposition of waste and leftover food. Concentrations of 1ppm or higher indicate a dangerous buildup of ammonia in your water, and can be harmful to your slider over the long term. In a properly cycled aquarium ammonia will be broken down by bacteria into nitrite very quickly.

Nitrite: Nitrite are created by the breakdown of ammonia by bacteria in your tank. If your tank is properly cycled you will not have any reading of nitrites. Just like the ammonia->nitrite conversion, the nitrite->nitrate conversion is performed by bacteria almost instantaneously. Like ammonia, a sustained concentration of 1ppm or more creates an unhealthy environment in your tank water.

Nitrate: Nitrate is the final product of the Nitrogen Cycle in your aquarium. Its presence indicates that the beneficial bacteria are doing their job of breaking waste down into this significantly less toxic byproduct. A tolerable range for nitrate levels is 20-40ppm, but in higher concentrations can be toxic. Nitrate levels can be managed with water changes, we go into the details of changes and cleaning below. Keeping plants in your tank also lowers nitrate levels, as plants use it for food.

pH: pH is a measurement of the acidity of your water. The pH scale runs from 0-14, with 0-6.9 being acidic, 7 neutral, and 7.1-14 being alkaline. The safe range for red-eared sliders is about 6-8. pH levels higher than this should be avoided as a high pH has the effect of multiplying the toxicity of any ammonia present in the water.


Tank Cleaning

A safe guideline for tank cleaning is to (in conjunction with water testing) do a water change of about 20-25% per week. Remember to treat the water with a water conditioner beforehand to remove chlorine/chlorinates. They can destroy your nitrogen cycle. The water change should be enough to keep you keep your nitrate level in check, and keep your sliders happy and healthy.

Never completely empty out your tank and scrub it down. This will cause the tank to lose its cycle and you will be starting from square one.

For proper cleaning, avoid disturbing your tank as much as possible. The focus is on minimal interruption of the ecosystem you have worked hard to cultivate.vFirst off, to remove waste effectively you’re going to want to invest in a good gravel vacuum. This will save you a lot of time and effort in removing waste and leftover food buildup.

Here’s a helpful video on how they work and how to use one:


If you have a tank with no substrate or minimal substrate, then a turkey baster also works well for spot cleaning. You can use it to suck up isolated pieces of leftover food or waste on the tank bottom.

Next, keep in mind that when you rinse the filter to clean it or clean off any of the tank ornaments, this should be done using tank water. At risk of sounding like a broken record, tap water will kill your beneficial bacteria and disrupt or destroy your cycle. You want to avoid introducing chlorine or chlorinates to your tank as all costs, and you need to be especially careful with your filter, which is where your beneficial bacteria build up.

Keep to these steps and monitor your water chemistry with weekly tests, and you should stay problem free!


Keep Reading: Red Eared Slider Care Sheet

  1. Tank Size and Setup
  2. Filter and Water Temperature
  3. Lighting/Heat Requirements
  4. The Nitrogen Cycle
  5. Tank Cleaning and Water Chemistry – Current Page
  6. Diet and Nutrition
  7. Illnesses and Injury
  8. Additional Reading and Resources