• Skip to main content
  • Skip to primary sidebar
  • Home
  • Bettas 101
    • Acclimation
    • All About Water
      • Nitrogen Cycle
      • Ph & Ammonia
      • Water Changes
    • Betta Fish Anatomy
    • Betta Vases
    • Choosing a Tank
    • Feeding Bettas
      • Food Myths
      • Frozen & Live Betta Food
    • Tankmates for Bettas
      • African Dwarf Frogs & Bettas
      • Apple Snails & Bettas
      • Neon Tetras & Bettas
      • Otocinclus Catfish & Bettas
      • Quarantine New Fish
    • Plakat Betta
    • Rosetail Betta
    • Veil-tail Betta
  • Sick Betta
    • Diseases and Treatment
    • Aging Bettas
    • Bloating and Constipation
    • Cotton Wool Disease
    • Dropsy
    • Fin Rot and Fin Loss
    • First Steps
    • Gill Hyperplasia
    • Ich
    • Popeye
    • Septicemia (Infection)
    • Swim Bladder Disorder
    • Sick Betta Symptom Checker
    • Velvet Disease
    • Wounded Betta
    • Fish Tank Granuloma
  • Behavior
    • Bubble Nests
    • Skittish Bettas
    • Tail Biting
  • Breeding Bettas
  • Equipment
  • Q & A
  • Other fish
  • Contact

Fish Care

Everything You Need to Know About Betta Fish

You are here: Home / Water Quality / KH / PH Crashes: The Roll of Carbonate Hardness (KH)

PH Crashes: The Roll of Carbonate Hardness (KH)


Ghost shrimp close up, originally uploaded by octopus.gallery.

Q: CR wrote,

I have a general aquarium question I hope you can help me with. I recently had what I think is a pH crash that quickly killed off my ghost shrimp and several small catfish. I can’t figure out what lead to this and would like to know how to avoid it from happening again.

A: When pH fluctuates in a short amount of time it can be very stressful to fish and especially so when it goes from basic (above 7.0) to acidic (below 7.0). When the pH falls like this we call it a pH crash. If it falls fast and hard enough it can lead to mass casualties. To avoid pH crashes we need to understand what keeps the pH stable under good conditions. Carbonate hardness (kh) is the measure of bicarbonate and carbonate ions in the water and when sufficient, will buffer the pH, keeping it stable. This is why we often refer to carbonate hardness as buffering capacity.

In simple terms, if your carbonate hardness (kh) is adequate your pH will be stable. To determine your kh a simple test kit can be purchased at any local fish store.

0 – 50 ppm very low
50 – 100 ppm low
100 – 200 ppm moderate
200 – 400 ppm high

If you find that your kh levels are very low you may want to add buffers to the water. Avoid the temptation to change the pH level directly with pH-Up, pH-Down or pH-Neutral. These products will cause your pH to fluctuate quickly and won’t solve the problem of inadequate buffering capacity. These quick fluctuations could lead to additional casualties. Adding natural buffers like baking soda to your water will raise your carbonate hardness and help to stabilize your pH. Though baking soda is readily available and inexpensive, some fish hobbyists prefer to buy a buffering agent from their fish store. They’re quite a bit more expensive than baking soda but do the job. If you prefer to buy buffers from a fish supply store, I recommend Kordon’s Dry AmQuel Plus Buffers. It’s a two-for-one in that it acts as both a water conditioner and a buffering agent.

To understand more about pH and it’s role in our aquarium visit Adjusting Aquarium pH Level from Nippyfish: A Betta Blog.


Filed Under: KH, pH, Water Quality

Reader Interactions

Comments

  1. Octopus says:

    Man, I’m glad I was vanity-googling today because it caused me to run across your fantastic blog! This is the first online explaination of the role of kH I’ve run across that makes any sort of sense. Thanks!

    Reply
  2. Christie says:

    Thanks Octopus! I appreciate the kind words. I mostly focused on low kh levels but I should mention that the converse is true also. High kh levels will keep your pH very stable and difficult to change. In most cases we don’t want to mess with our pH levels but in the rare cases we do. A high kh level will make it very difficult to alter the pH. Welp, just wanted to add that last little note. Thanks again for leaving a comment.
    ~Christie

    Reply
  3. Anonymous says:

    Glad you add the last part about the high KH level. I was looking for info on that! Thanks a lot!

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Primary Sidebar

Search


Recent Posts

  • Cool Betta Fish Tank Ideas
  • How Long Do Betta Fish Live For? – 5 Helpful Tips For a Long and Happy Life
  • 3 Gallon Fish Tank for Betta
  • 10 Gallon Aquarium Stands and Cabinets
  • How Much Do Betta Fish Cost to Buy and Care For?

NippyFish Facebook Page

Visit the NippyFish Facebook Page

Featured Posts

Complete Guide to Betta Fish Diseases and Treatment

This complete guide on Betta fish illnesses and diseases from A-Z will help you pinpoint what is wrong with your Betta and how to treat it.

The 4 Most Common Signs of Illness in Betta Fish

This article focuses on the 4 most common signs of illness in Betta fish.

Betta Fish Tank Setup – A Detailed Guide For Beginners

This article will be providing a detailed beginners guide on how to setup a tank for your Betta fish.

Top 12 Betta Fish Toys

This article has a list of some of our favorite Betta fish toys. Don’t have a bored Betta.

Setup an Aquatic Plant Environment For Your Betta

Having a healthy plant in your tank will help to improve the water quality by filtering out waste and removing some of the CO2 that’s produced by your fish.

Copyright © 2025 All Rights Reserved | NippyFish | Privacy Policy

Nippyfish.net is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.