I'm moving to a new location that uses geothermal water. Generally, when I top off/replace water for my betta, I get my water to the correct temperature, add the stress coat + to remove chemicals, and add it in.

But I am struggling to find any information on geothermal water and chemicals I should watch out for. The cold water is your usual tap/city water.

So, I can potentially make sure it's only cold water, and let it warm up by the radiator before I add it to his tank. I'm worried about how much residue of whatever is in geothermal water will end up in the cold water. Or, I can buy pre-treated water (which would be a hassle).

Maybe I'm overthinking and my little dude will be just fine!

  • geothermal water do very often contain a large amount of dissolved minerals,you need to post an complete analysis of the water from your water suplyer.i do not know of any company that uses hot water from the ground to suply drinking water. Commented Jan 27, 2019 at 6:08
  • So it sounds like I should just try and use only cold, cold water and then warm it up, so I'm not risking anything from the geothermal?
    – Gwendolyn
    Commented Jan 28, 2019 at 19:15
  • i think i misunderstand your question,geothermal water is what you find in hot springs,and geothermal heat is used to heat water from your water company and is the same as your cold water only heated. Commented Jan 29, 2019 at 4:40
  • Yes, it is heated by geothermal. The cold water is simply city water. (It’s a really old set up). However, in the process to heat the water, the water will contain sulfites, high levels of iron, etc. I’m not an expert on this water or all the details. I’m simply wondering if a water condition will work in water like this or not.
    – Gwendolyn
    Commented Jan 29, 2019 at 5:08

1 Answer 1


No, water conditioner will not work in this water.

What you need to do is use the cold water. Fill the containers with tap water, add the water conditioner and let it stand overnight so it gets heated up a little.

It is important to avoid using water that is too cold when you do the water changes. Fish have no problems with a slight drop in temperature as long as it is gradual.

Be careful not to use water that is too hot (hotter than the water in your tank).

Try not to change a large amount of water at once. It is better to change about 10% each day over five days.

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