Help with GH and KH!

clovervalley

I just tested my gh and kh for the first time, and I’m not really sure what they mean. My pH is around 8.1-8.2 and stays at that level.

When I tested the kh, it took 15 drops to change color which means that I am in the 200-400ppm range according to the test kit.

However, when I tested gh it took 2 drops to change. Why are they so different? Did I do something wrong? What does this mean for my water?

I will put pictures below of my test kit and test tubes


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IMG_1863.JPG
IMG_1862.JPG

IMG_1864.JPG
KH is yellow and GH is green
 

Joshaeus

KH measures the amount of carbonates in the water, while GH measures how much calcium and magnesium is in the water (E.G calcium carbonate would increase both GH and KH, but sodium bicarbonate would only increase KH). Since KH and GH measure different substances, the fact that they are so different probably doesn't mean you messed the test up...your tap water just has far more carbonates than GH.

As to why these values are important...carbonates are the primary alkaline buffers in aquariums (they keep the PH above 7...tanks with low KH are more likely to experience PH shifts) while many fish and inverts need significant GH levels to acquire the minerals required to build their skeletons/shells/etc. Large (3 degree or more) changes of KH within a short period is very stressful on all the life in the tank; such changes are frequently lethal to more delicate specimens such as shrimp, which often die within a few weeks after experiencing such a shocking change. Conversely, many aquatic plants can use carbonates in place of carbon dioxide for photosynthesis, making them more likely to thrive in low tech tanks but potentially reducing the PH if they remove too much carbonate in the process.
 

oldsalt777

Hello...

The only thing you need to make sure to do in keeping aquarium fish is that the chlorine and chloramines are detoxified in the tap water. You don't need to know anything about the pH, hardness or any other water chemistry subject. These aren't necessary if you simply want to keep fish available at the local pet store. A water treatment is the only additive you need to put into the tank water to make it livable for the fish. Putting other chemicals into the water makes the hobby more confusing and significantly decreases your chances for success.

Old
 

Joshaeus

Hello...

The only thing you need to make sure to do in keeping aquarium fish is that the chlorine and chloramines are detoxified in the tap water. You don't need to know anything about the pH, hardness or any other water chemistry subject. These aren't necessary if you simply want to keep fish available at the local pet store. A water treatment is the only additive you need to put into the tank water to make it livable for the fish. Putting other chemicals into the water makes the hobby more confusing and significantly decreases your chances for success.

Old

Most fish in a pet store are captive bred and more tolerant of varied PH, KH, GH, etc values than their wild ancestors...however, a few decades of captive breeding does not alter the fact that these fish have adapted for thousands or millions of years to waters within a certain range of parameters. While fish may survive outside of those values, they will do better if the tank's parameters are reasonably close to those of their natural habitat (many tetras, for example, tend to accumulate a lot of calcium in their kidneys in hard water, shortening their life span considerably)...for those of us who don't want to try to alter our water, the easiest solution is simply to pick fish that naturally prefer whatever parameters our water has out of the tap.

I forgot to mention this earlier...the PH has a significant effect on the nitrogen cycle in the aquarium. Ammonia in the aquarium is split between actual ammonia (NH3) and (mostly) harmless ammonium (NH4). In acidic water, ammonia becomes very scarce compared to ammonium, but the beneficial nitrifying bacteria work poorly because they need carbonates (inevitably scarce in acidic water) to oxidize ammonia to nitrite; the nitrifying bacteria work far better in hard water, but a much larger fraction of the ammonium is converted to ammonia and this will punish you quickly if the tank suffers an ammonia spike. It's a catch 22, really...
 

Momgoose56

I just tested my gh and kh for the first time, and I’m not really sure what they mean. My pH is around 8.1-8.2 and stays at that level.

When I tested the kh, it took 15 drops to change color which means that I am in the 200-400ppm range according to the test kit.

However, when I tested gh it took 2 drops to change. Why are they so different? Did I do something wrong? What does this mean for my water?

I will put pictures below of my test kit and test tubes


IMG_1861.JPG
IMG_1863.JPG
IMG_1862.JPG

IMG_1864.JPG
KH is yellow and GH is green
I agree, usually they are closer in number and frequently the GH is higher than the KH, but the tests measure two completely different properties of water. The GH measures dissolved solids and the KH measures the carbonate/bicarbonate, (negatively charged 'molecules' essentially) that will break down further in the presence of acid that way 'resisting pH change' I do think your GH could have used one more drop though it's almost not green enough. Try it with one more drop...
 

oldsalt777

Hello again...

Only want to encourage the new fish keeper to resist the temptation to play around with the water chemistry. It's fine to study the chemistry end of things, to understand alkaline or acidic water and such, but don't try to maintain a particular water chemistry, you simply need to adopt an aggressive water change routine that will give your fish a steady water chemistry. This is all they need for good health.

Old
 

Joshaeus

Understood...it's still useful to know your parameters to help you choose your fish, so I'd still recommend occasionally checking them. This could also help pin down problems with the tank if/when they appear.
 

clovervalley

Hello again...

Only want to encourage the new fish keeper to resist the temptation to play around with the water chemistry. It's fine to study the chemistry end of things, to understand alkaline or acidic water and such, but don't try to maintain a particular water chemistry, you simply need to adopt an aggressive water change routine that will give your fish a steady water chemistry. This is all they need for good health.

Old

I’ve been in the hobby for almost two years now, I just had never looked into the KH/GH! I’m not planning on artificially changing anything, but was curious on the mineral content since I recently purchased mystery snails and wanted to make sure I was providing enough calcium. It seems I have very well-buffered water, and I have began adjusting the fish I get with my pH and water conditions instead of worrying about lowering pH. I was fortunate that my angel survived and acclimated to my water before I knew they were better with softer water. My swordtails love the hard water though!

I agree, usually they are closer in number and frequently the GH is higher than the KH, but the tests measure two completely different properties of water. The GH measures dissolved solids and the KH measures the carbonate/bicarbonate, (negatively charged 'molecules' essentially) that will break down further in the presence of acid that way 'resisting pH change' I do think your GH could have used one more drop though it's almost not green enough. Try it with one more drop...

I was confused about how much the color was supposed to change for GH... for KH it was much more obvious. I did one GH test with 3 drops but I looked pretty much the same as 2 drops. I will try again right now and see. The starting orange color wasn’t dark at all! I was surprised by how low the GH tested as, I always get hard water lines so I thought there were more minerals than I tested.
 

KinderScout

Weekly Tetra test strips just before a water change are a simple way to keep an eye on things without any real hassle. The measurements to keep things stable don't have to be wildly accurate - they'll reassure you your nitrite/chlorine is zero and you'll soon see that the colours for GH/KH don't tend to change which is what you want. We only occasionally now use the liquid tests for nitrate/nitrite/ammonia and only after either losing or adding fish. We would also do a full barrage of tests if the strip looked different than what we would expect but that has not happened in over two years.
The only time we've needed an accurate measurement of KH is when adding CO2 for the first time - it's worth remembering that KH/PH/CO2 are directly linked - if you know your KH and PH you know exactly how much CO2 is in the water.
 

clovervalley


IMG_1865.JPG
This is the color after 5 drops- darker green but even the drops before looked green as well, only lighter. I am having trouble seeing the orange color.
 

oldsalt777

Understood...it's still useful to know your parameters to help you choose your fish, so I'd still recommend occasionally checking them. This could also help pin down problems with the tank if/when they appear.

Hello Josh...

If you're interested in this information, then by all means study it up. Fish at the local pet store will be living in the same water source you have at home. So, by simply treating the water to detoxify the chemicals the public water people put into the tap water to make it safe to drink and setting up a sound water change routine, you'll not need to do or know more than this to keep a healthy tank with healthy fish. If you keep things simpler, you'll be more successful. If you change a lot of water and do it every few days, you won't have any tank problems.

Old
 

Momgoose56

I’ve been in the hobby for almost two years now, I just had never looked into the KH/GH! I’m not planning on artificially changing anything, but was curious on the mineral content since I recently purchased mystery snails and wanted to make sure I was providing enough calcium. It seems I have very well-buffered water, and I have began adjusting the fish I get with my pH and water conditions instead of worrying about lowering pH. I was fortunate that my angel survived and acclimated to my water before I knew they were better with softer water. My swordtails love the hard water though!



I was confused about how much the color was supposed to change for GH... for KH it was much more obvious. I did one GH test with 3 drops but I looked pretty much the same as 2 drops. I will try again right now and see. The starting orange color wasn’t dark at all! I was surprised by how low the GH tested as, I always get hard water lines so I thought there were more minerals than I tested.
For snails, a higher GH (Calcium/Magnesium) is better but many here supplement snail diets with home made 'snello' with powdered calcium or calcium/magnesium powder added. I make a batch, slice it in disks and freeze it. For my many mystery snails, one batch lasts months and they LOVE it.
 

clovervalley

For snails, a higher GH (Calcium/Magnesium) is better but many here supplement snail diets with home made 'snello' with powdered calcium or calcium/magnesium powder added. I make a batch, slice it in disks and freeze it. For my many mystery snails, one batch lasts months and they LOVE it.

I did make some! It took them a day to adjust but they definitely enjoy it. With the snello and the cuttlebone I have in my tank, they should be good on calcium, right?
 

Momgoose56

I did make some! It took them a day to adjust but they definitely enjoy it. With the snello and the cuttlebone I have in my tank, they should be good on calcium, right?
Right!
 

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