Help With Kh/gh And What It Means

smallfries
  • #1
Hey all, I'm setting up my tank and got an API GH/KH test kit. I've been reading articles on what these mean, but I'm so confused. Most talk about PH, but I don't know how to get PH from KH. Here are my readings, and my question is, should I be concerned, or am I okay? I'm looking at getting a dwarf gourami, ember tetras, and pygmy corys, which according to aqadvisor, should have pH range: 7 - 7.5 and hardness range: 10 - 15 dH:

KH: 196.9 ppm DH: 286.4 ppm

Any **** would be appreciated, 'cuz I am confused
 
TexasDomer
  • #2
pH can't be calculated from KH, and vice versa. They are different things.

Here's some more info:
pH GH and KH

You're fine, all of those fish are adaptable to a range of KH, GH, and pH. Aqadvisor isn't accurate, so I wouldn't use it for stocking. We can help you with your stocking plan if you're interested.
 
smallfries
  • Thread Starter
  • #3
pH can't be calculated from KH, and vice versa. They are different things.

Here's some more info:
pH GH and KH

You're fine, all of those fish are adaptable to a range of KH, GH, and pH. Aqadvisor isn't accurate, so I wouldn't use it for stocking. We can help you with your stocking plan if you're interested.

Thank you for the info! As long as my water is okay.

I have a 10 gallon Marineland tank with a Penguin 75 Biowheel filter (the one that came with the tank kit). I'm planning on putting a Dwarf Gourami, 6 Ember tetras, 4 pygmy corys, and probably a nerite snail. I think Aqadvisor put that at 63% stocking level.
 
TexasDomer
  • #4
You have stocking issues, if you'd like to discuss it. Aqadvisor isn't good.
 
smallfries
  • Thread Starter
  • #5
Okay, is that overstocked? What if I took out the corys?
 
TexasDomer
  • #6
In a 10 gal, I wouldn't keep a DG or cories. Cories should be in larger groups, and because of their activity level, a 10 gal isn't big enough. DGs also need a bigger tank. You could do something like this?

10x Ember tetra
2x Male endlers
2-4x Amano shrimp
10x Cherry shrimp
 
smallfries
  • Thread Starter
  • #7
What about Neons or Cardinals? I was going to go with Embers since I believe they're the smallest tetras and I wanted to be able to accommodate the DG. But if I can keep a more flashy variety, I'd like to.
 
TexasDomer
  • #8
Both need larger tanks than a 10 gal.

What about celestial pearl danios or emerald dwarf rasboras instead of ember tetra? They're a bit flashier.
 
smallfries
  • Thread Starter
  • #9
Thanks for the suggestions! How many of each can I keep if go with the male endlers and shrimp?
 
TexasDomer
  • #10
How many male endlers did you want?
 
smallfries
  • Thread Starter
  • #11
If I went with 2 like you suggested.
 
TexasDomer
  • #12
Same number as it would be with the ember tetra, either 10 CPDs or 10 emerald dwarf rasbora.
 
smallfries
  • Thread Starter
  • #13
Thank you very much!
 
Chandell
  • #14
HI guys, I have a 38 gallon tank with seven false juliI cories and one Betta. I use reverse osmosis water and equilibrium. I think I may need an alkaline buffer to raise the KH but my PH is always at least 7.5 (could be higher) I use API freshwater testing kit and it only goes up to 7.5. the colour is always dark blue. So I don't want to raise ph. I'm not sure what my readings mean for KH. I use 6 drops which equals 107.4 so with my cories and Betta I have no idea if that is okay. If I need to raise the hardness what should I do?
 
ValerieAdams
  • #15
If you're doing 6 drops, that's about 6 Kh (more people refer to it in this way instead of ppm. I don't know why, it through me off at first). I wouldn't raise it, it's in the middle range for both fish
 
sfsamm
  • #16
Your kH is fine at 6 I would not adjust it nor do anything differently than you are now. Just continue monitoring and if it starts to dip then action may be required.
 
Chandell
  • #17
If you're doing 6 drops, that's about 6 Kh (more people refer to it in this way instead of ppm. I don't know why, it through me off at first). I wouldn't raise it, it's in the middle range for both fish
So happy to hear that! Thank you!

Your kH is fine at 6 I would not adjust it nor do anything differently than you are now. Just continue monitoring and if it starts to dip then action may be required.
That's great, thanks so much!
 
georgelee1000
  • #18
Your kh is fine. Stability is more important than your ph. So I don’t recommend chemically alters it. But you can use catappa leaf or other leaf litter and/or driftwood. These will lower your water ph slowly and stably. Maybe not to much with a kh of 6. But hey, your betta will love these tannins.
 
ystrout
  • #19
You're not using any KH adjusting products?

It sounds like you know Equilibrium only affects GH (which has no affect on PH, just the minerals fish use). But 6 KH is perfect. When I used RO water, I tried to get my water around that level anyways.

But if your RO water has 6 KH, it's probably not working properly. Most RO water I've used has GH and KH of under 2 or 3. A perfect RO system would give you GH and KH or 0 and you'd need to use Equilibrium for GH and Acid/alkaline buffer to optimize KH.

So for now, just keep using that water (while adding Equilibrium) as it's perfect for your fish. But if you change the RO cartridges, expect the KH to be closer to 0 so you'll need to use a product then.
 
Chandell
  • #20
You're not using any KH adjusting products?

It sounds like you know Equilibrium only affects GH (which has no affect on PH, just the minerals fish use). But 6 KH is perfect. When I used RO water, I tried to get my water around that level anyways.

But if your RO water has 6 KH, it's probably not working properly. Most RO water I've used has GH and KH of under 2 or 3. A perfect RO system would give you GH and KH or 0 and you'd need to use Equilibrium for GH and Acid/alkaline buffer to optimize KH.

So for now, just keep using that water (while adding Equilibrium) as it's perfect for your fish. But if you change the RO cartridges, expect the KH to be closer to 0 so you'll need to use a product then.
Oh okay. I did change the filters about six months ago. My GH reading is also 6 drops. Hope that's okay. Thanks so much for your help. Do you think I would be better off using my tap water?

Your kh is fine. Stability is more important than your ph. So I don’t recommend chemically alters it. But you can use catappa leaf or other leaf litter and/or driftwood. These will lower your water ph slowly and stably. Maybe not to much with a kh of 6. But hey, your betta will love these tannins.
Thanks. I'm going to order an Indian almond leaf.
 
ystrout
  • #21
If your GH and KH is 6, that's pretty much perfect for bettas and cories. I wouldn't add any Equilibrium or KH adjusting products.

I think that the water you may be getting from your RO and the tap may be very similar though. It sounds like the RO filter isn't really doing its job. That said, you probably should be treating your RO water with Prime in case and Chlorine is getting through the filter.
So it shouldn't matter whether you use your RO or tap. Just check the parameters of each. If you keep using RO water and end up changing the filters, just be aware that it will likely bring your KH and GH down to 0 and you'll need to add back both GH and KH minerals!

Good luck!
 
Chandell
  • #22
If your GH and KH is 6, that's pretty much perfect for bettas and cories. I wouldn't add any Equilibrium or KH adjusting products.

I think that the water you may be getting from your RO and the tap may be very similar though. It sounds like the RO filter isn't really doing its job. That said, you probably should be treating your RO water with Prime in case and Chlorine is getting through the filter.
So it shouldn't matter whether you use your RO or tap. Just check the parameters of each. If you keep using RO water and end up changing the filters, just be aware that it will likely bring your KH and GH down to 0 and you'll need to add back both GH and KH minerals!

Good luck!
Oh shoot okay. Well I have been adding the equilibrium every week. So I guess I will stop using that and start using prime. And maybe find out where I can have my water tested. Thank you


Just thinking...if my ro system is not working then wouldn't my ammonia be off. It is always at 0, I think maybe once or twice may have climbed to .25?
 
AquaticJ
  • #23
Just thinking...if my ro system is not working then wouldn't my ammonia be off. It is always at 0, I think maybe once or twice may have climbed to .25?
No your ammonia should be zero in a cycled tank and also, most tap water is 0 anyway. Did you buy just the GH/KH testing kit and not the API master kit?

In your other thread I had told you to buffer your KH because a properly working RO unit would easily bring the KH to zero. So as ystrout said, it’s not working. It’s been over a year since changing my filters in my RODI unit and the GH and KH are still 0.
 
Chandell
  • #24
No your ammonia should be zero in a cycled tank and also, most tap water is 0 anyway. Did you buy just the GH/KH testing kit and not the API master kit?

In your other thread I had told you to buffer your KH because a properly working RO unit would easily bring the KH to zero. So as ystrout said, it’s not working. It’s been over a year since changing my filters in my RODI unit and the GH and KH are still 0.
I do have the API master kit and everything is always the same. Nitrate 0, nitrite 20, ammonia 0 and ph have 7.5. I always thought the equilibrium is what was being up my KH. Now I am as confused as I was when I started this hobby lol. My poor fish!
 
AquaticJ
  • #25
Measure your GH and KH of your pure RO water and let me know what it is, that will solve this!
 
Chandell
  • #26

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548D8368-EB1A-4939-9D5C-8ACBE83E894C.jpeg
Measure your GH and KH of your pure RO water and let me know what it is, that will solve this!
Okay so I tested my ro water using the API GH and KH liquid test kit. KH was 4 drops which equals 71.6. The Gh was supposed to turn from Orange to green. I posted pictures from the first drop to the third. The first drop was just clear not Orange?
 
ystrout
  • #27
I'm going to give you a long answer that covers all the basics. This stuff is super confusing so we all understand where you're coming from. Let me know if I missed anything!

KH and GH are both measures of minerals in the water. GH stands for general hardness and measures the mineral content in the water that the fish need for their health. If your GH is 0, your fish will actually lose minerals from their body and die from osmotic shock. This happens because osmosis occurs in the fish's gills/aquarium water and minerals from the fish's body move into the water until equilibrium occurs (since the fish has more minerals in its body than the water has). Unfortunately, this water will suck out all of the fish's minerals and it will die before equilibrium occurs.

KH measures carbonate hardness. These minerals keep your PH stable and have a correlation with PH. High KH means your PH won't change, and it will likely be pretty high. 4 KH is enough that your PH won't fluctuate.

Now that the basics are covered, the reason we're saying your RO unit isn't working is that RO water should have NO minerals at all. This means the GH and KH would both be zero. This water would swing PH a lot (since KH is 0) and would suck the minerals out of your fish's body (since GH is 0). So you can't use this water directly in your aquarium. You have to "treat" it by using equilibrium to raise GH and SeaChem products like acid buffer and alkaline buffer to bring KH to an optimum level.

But your water has a good KH level and measurable GH levels. This is probably from old fitlers. They don't last forever, and if you use yours frequently, the filters are probably clogged up. This is also why I recommend using Prime with your RO water. Since the filters are clogged, they probably aren't capturing all of the chlorine. So you want to dose with Prime to remove the Chlorine (if there is any).

Now to your readings. Your KH is 4 and your GH is around 1-2. The KH is good and you don't need to change it. Your RO unit does a good job removing GH minerals so you'll need to add those back. Keep using equilibrium until your GH is above 4, ideally around 6-8 for the fish you have.

Tap water shouldn't have ammonia. So there's nothing for your RO unit to remove. And if there is any, a cycled tank should digest it quickly.

And remember, if you replace your RO filter cartridges, your GH and KH will get back to 0! So you need to treat this water with Equilibrium and KH adjusting products.
 
Chandell
  • #28
I'm going to give you a long answer that covers all the basics. This stuff is super confusing so we all understand where you're coming from. Let me know if I missed anything!

KH and GH are both measures of minerals in the water. GH stands for general hardness and measures the mineral content in the water that the fish need for their health. If your GH is 0, your fish will actually lose minerals from their body and die from osmotic shock. This happens because osmosis occurs in the fish's gills/aquarium water and minerals from the fish's body move into the water until equilibrium occurs (since the fish has more minerals in its body than the water has). Unfortunately, this water will suck out all of the fish's minerals and it will die before equilibrium occurs.

KH measures carbonate hardness. These minerals keep your PH stable and have a correlation with PH. High KH means your PH won't change, and it will likely be pretty high. 4 KH is enough that your PH won't fluctuate.

Now that the basics are covered, the reason we're saying your RO unit isn't working is that RO water should have NO minerals at all. This means the GH and KH would both be zero. This water would swing PH a lot (since KH is 0) and would suck the minerals out of your fish's body (since GH is 0). So you can't use this water directly in your aquarium. You have to "treat" it by using equilibrium to raise GH and SeaChem products like acid buffer and alkaline buffer to bring KH to an optimum level.

But your water has a good KH level and measurable GH levels. This is probably from old fitlers. They don't last forever, and if you use yours frequently, the filters are probably clogged up. This is also why I recommend using Prime with your RO water. Since the filters are clogged, they probably aren't capturing all of the chlorine. So you want to dose with Prime to remove the Chlorine (if there is any).

Now to your readings. Your KH is 4 and your GH is around 1-2. The KH is good and you don't need to change it. Your RO unit does a good job removing GH minerals so you'll need to add those back. Keep using equilibrium until your GH is above 4, ideally around 6-8 for the fish you have.

Tap water shouldn't have ammonia. So there's nothing for your RO unit to remove. And if there is any, a cycled tank should digest it quickly.

And remember, if you replace your RO filter cartridges, your GH and KH will get back to 0! So you need to treat this water with Equilibrium and KH adjusting products.
Wow okay. First I want to thank you so much for taking the time to explain this to me. I really appreciate it. I love my fish! So my KH is good but my GH is not. I went to buy alkaline buffer and acid buffer but it says it Is to make Ph higher and lower which mine is already high. So do I want to add one of those things to my tank. Is that what will help my GH?

I did buy prime I will add it in one week once I do water change. I use 5 gallon pails to fill my tank so can I add prime directly to the tank or to the pails?

Do you think I should maybe switch to tap water. I only have a small ro system and fill four 5 gallon pails weekly so it probably does get clogged. The fish have been living in this water for a year to a year and a half. Will it hurt to make the switch?


I'm really feeling like I want to switch to tap water. I am far from being a good fish keeper (although I haven't lost a fish for a really long time now ) I started with a small 15 gallon someone gave me and set this 38 gallon up January 2017. Regarding my ro system....I know nothing! My dad gave it to me, set it up and changes the filters. And he knows nothing about fish keeping. What are your thoughts to me switching water?

Sorry one more question. Do you think I should add prime now or wait until water change? I think my Betta is in bad condition. He never swims around...ever. just to go from one spot to another. My cories are never out either I never see them, only the last two that were added a few minutes that ago are out and active.
 
ystrout
  • #29
Sorry one more question. Do you think I should add prime now or wait until water change? I think my Betta is in bad condition. He never swims around...ever. just to go from one spot to another. My cories are never out either I never see them, only the last two that were added a few minutes that ago are out and active.
I would definitely add Prime now. Dose the entire tank with the amount recommended on the back of the bottle. A 40 gallon tank should use about 4 ml which is about 4 threads on the cap of Prime. You can also buy a 1ML syringe which makes dosing easier. But if you don't have one, I would use more Prime than less.

And I would absolutely switch to tap water. There's honestly no reason to use RO water for a betta and cories, especially if the RO unit isn't working properly! I actually use tap water for all 3 of my tanks. My tap water has very high GH and KH (I live in San Diego) and my fish are extremely healthy. They actually don't care about the PH, GH, or KH, as long as it's stable and doesn't change drastically instantly. So switching to tap water won't hurt them at all. Just don't do a 100% water change and fill the tank with tap water. That will hurt them. You need to do 25% water changes going forward. That will acclimate them and in a month or so, your tank parameters will match your tap water.

Lastly, going forward, add the Prime to the water before doing water changes. Pretty much everyone who keeps fish as pets uses 5 gallon buckets for their water changes. So we just fill the bucket up, add .5 to 1ml of Prime, stir it for 20 seconds, then pour it into the tank.
 
Cichlidude
  • #30
I do have the API master kit and everything is always the same. Nitrate 0, nitrite 20, ammonia 0 and ph have 7.5. I always thought the equilibrium is what was being up my KH. Now I am as confused as I was when I started this hobby lol. My poor fish!
Are you sure those are the correct numbers???
 
Chandell
  • #31
I would definitely add Prime now. Dose the entire tank with the amount recommended on the back of the bottle. A 40 gallon tank should use about 4 ml which is about 4 threads on the cap of Prime. You can also buy a 1ML syringe which makes dosing easier. But if you don't have one, I would use more Prime than less.

And I would absolutely switch to tap water. There's honestly no reason to use RO water for a betta and cories, especially if the RO unit isn't working properly! I actually use tap water for all 3 of my tanks. My tap water has very high GH and KH (I live in San Diego) and my fish are extremely healthy. They actually don't care about the PH, GH, or KH, as long as it's stable and doesn't change drastically instantly. So switching to tap water won't hurt them at all. Just don't do a 100% water change and fill the tank with tap water. That will hurt them. You need to do 25% water changes going forward. That will acclimate them and in a month or so, your tank parameters will match your tap water.

Lastly, going forward, add the Prime to the water before doing water changes. Pretty much everyone who keeps fish as pets uses 5 gallon buckets for their water changes. So we just fill the bucket up, add .5 to 1ml of Prime, stir it for 20 seconds, then pour it into the tank.
Awesome! Thank you so much I will do exactly what you said. One more thing, when adding tap water that will probably change my oh so that will be okay?

Are you sure those are the correct numbers???
Yes, other than the ph as my chart only goes up to 7.5. I feel it may be higher as the blue colour seems a bit darker
 
Cichlidude
  • #32
Yes, other than the ph as my chart only goes up to 7.5. I feel it may be higher as the blue colour seems a bit darker
Are you sure....

Nitrate 0, nitrite 20, ammonia 0 and ph have 7.5.
 
ystrout
  • #33
Awesome! Thank you so much I will do exactly what you said. One more thing, when adding tap water that will probably change my oh so that will be okay?
Not sure if you meant KH, ph, or GH. But it's fine for any of these to raise by adding tap water.

Bettas and cories don't mind low or high mineral content or PH. Some fish like discus and other cichlids need hard water (high mineral content) and high ph, but bettas and cories couldn't care less.
 
ystrout
  • #34
Are you sure....

Nitrate 0, nitrite 20, ammonia 0 and ph have 7.5.
My guess is she meant, 0 ammonia, 0 nitrite, and 20 nitrate...
 
Cichlidude
  • #35
My guess is she meant, 0 ammonia, 0 nitrite, and 20 nitrate...
Well I'm guessing that too. Just want to be sure.
 
Chandell
  • #36
Are you sure....

Nitrate 0, nitrite 20, ammonia 0 and ph have 7.5.
Well that's what I've been getting for the past year. I am gone tomorrow but Wednesday I will test the water again.

Well I'm guessing that too. Just want to be sure.
Oh ya I could have mixed the two up lol sorry.
 
Chandell
  • #37
Not sure if you meant KH, ph, or GH. But it's fine for any of these to raise by adding tap water.

Bettas and cories don't mind low or high mineral content or PH. Some fish like discus and other cichlids need hard water (high mineral content) and high ph, but bettas and cories couldn't care less.
I meant ph. Thank you so much I'm am so glad to hear I can switch to tap water and all will be good.
 
Chandell
  • #38
I would definitely add Prime now. Dose the entire tank with the amount recommended on the back of the bottle. A 40 gallon tank should use about 4 ml which is about 4 threads on the cap of Prime. You can also buy a 1ML syringe which makes dosing easier. But if you don't have one, I would use more Prime than less.

And I would absolutely switch to tap water. There's honestly no reason to use RO water for a betta and cories, especially if the RO unit isn't working properly! I actually use tap water for all 3 of my tanks. My tap water has very high GH and KH (I live in San Diego) and my fish are extremely healthy. They actually don't care about the PH, GH, or KH, as long as it's stable and doesn't change drastically instantly. So switching to tap water won't hurt them at all. Just don't do a 100% water change and fill the tank with tap water. That will hurt them. You need to do 25% water changes going forward. That will acclimate them and in a month or so, your tank parameters will match your tap water.

Lastly, going forward, add the Prime to the water before doing water changes. Pretty much everyone who keeps fish as pets uses 5 gallon buckets for their water changes. So we just fill the bucket up, add .5 to 1ml of Prime, stir it for 20 seconds, then pour it into the tank.
HI ystrout, just wondering when I start adding 25% tap water should I do this weekly or every two weeks or monthly?
 
ystrout
  • #39
HI ystrout, just wondering when I start adding 25% tap water should I do this weekly or every two weeks or monthly?
Do it however frequently you do water changes.

Normally this is weekly unless you have a very lightly stocked tank. Even then, weekly is still safest.

My 75 gallon community tank is pretty lightly stocked. I do 15-20 gallon water changes weekly and it keeps my water pristine. I could get away with doing it less frequently, but weekly just ensures your water is always perfect!
 
Chandell
  • #40
Do it however frequently you do water changes.

Normally this is weekly unless you have a very lightly stocked tank. Even then, weekly is still safest.

My 75 gallon community tank is pretty lightly stocked. I do 15-20 gallon water changes weekly and it keeps my water pristine. I could get away with doing it less frequently, but weekly just ensures your water is always perfect!
Okay thanks so weekly. My tank is 38 gallon and I have always done 20 gallon changes weekly. I would like to do every two weeks as it's so much work but whatever keeps my fish healthy and happy
 

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