How to raise KH without touching GH

[TanTann the fish man]

I've been finding a ton of "mixed" opinions on this topic. So my GH is >301 but my KH usually always reads 0. PH is around 6.4-6.8. What is the best way to raise my KH without increasing my GH? Is baking soda the answer or is something else better?

[face]

If you have kh in your tap water the best way is just water changes imo if not then ya baking soda would work what numbers are you looking for?

[HelplessNewbie]

I have same situation. For my small tanks, I just use Seachem Alkaline buffer in the change water to raise the KH without affecting GH. These also have small amounts of crushed coral to alowly raise the KH.

In my 65 gallon, we happen to have a large coral rock that keeps the KH stable.

[TanTann the fish man]

On 7/14/2024 at 2:13 PM, face said:

If you have kh in your tap water the best way is just water changes imo if not then ya baking soda would work what numbers are you looking for?

I'm really just wanting some measurable KH to help prevent any ph crashes

On 7/14/2024 at 2:21 PM, HelplessNewbie said:

I have same situation. For my small tanks, I just use Seachem Alkaline buffer in the change water to raise the KH without affecting GH. These also have small amounts of crushed coral to alowly raise the KH.

In my 65 gallon, we happen to have a large coral rock that keeps the KH stable.

Ok I'll definitely look into the alkaline buffer. This is a 90 gallon tank, the coral rock does help with KH? Do you notice any change in your GH with that?

[HelplessNewbie]

On 7/14/2024 at 2:23 PM, TanTann the fish man said:

This is a 90 gallon tank, the coral rock does help with KH? Do you notice any change in your GH with that?

I didn't notice any difference in GH. I would suggest first keeping the coral rock in a bucket of dechlorinated water and observe/measure for a few weeks how much it will affect your parameters. 

[TanTann the fish man]

On 7/14/2024 at 3:52 PM, HelplessNewbie said:

I didn't notice any difference in GH. I would suggest first keeping the coral rock in a bucket of dechlorinated water and observe/measure for a few weeks how much it will affect your parameters. 

Awesome great idea. Thanks for the info!

[Pepere]

Crushed coral will raise GH as well as KH.

Baking soda adds Sodium.

Seachem Alkaline buffer raises KH without affectingGH and does notadd Sodium.

 

1 teaspoon Alkaline Buffer added to 20 gallons of water will raise KH 2.8 degrees.

[TanTann the fish man]

On 7/14/2024 at 6:00 PM, Pepere said:

Crushed coral will raise GH as well as KH.

Baking soda adds Sodium.

Seachem Alkaline buffer raises KH without affectingGH and does notadd Sodium.

 

1 teaspoon Alkaline Buffer added to 20 gallons of water will raise KH 2.8 degrees.

Does Seachem Alkaline buffer affect PH at all?

[Galabar]

On 7/14/2024 at 3:00 PM, Pepere said:

Crushed coral will raise GH as well as KH.

Baking soda adds Sodium.

Seachem Alkaline buffer raises KH without affectingGH and does notadd Sodium.

 

1 teaspoon Alkaline Buffer added to 20 gallons of water will raise KH 2.8 degrees.

Seachem Alkaline Buffer is a Sodium Bicarbonate based buffer:

https://www.seachem.com/alkaline-buffer.php

Edited July 14 by Galabar

[face]

On 7/14/2024 at 2:23 PM, TanTann the fish man said:

I'm really just wanting some measurable KH to help prevent any ph crashes

Ok I'll definitely look into the alkaline buffer. This is a 90 gallon tank, the coral rock does help with KH? Do you notice any change in your GH with that?

I’m in a similar boat I tried crushed coral it razed my gh by about 1 degrees in 2 weeks I’ve started to add a quarter of a teaspoon of baking soda every week it doesn’t even add 1DKH but it’s enough to keep the ph about 6 

 

On 7/14/2024 at 6:51 PM, TanTann the fish man said:

Does Seachem Alkaline buffer affect PH at all?

yes it will increase ph just like baking soda

[Pepere]

On 7/14/2024 at 6:51 PM, Galabar said:

Seachem Alkaline Buffer is a Sodium Bicarbonate based buffer:

https://www.seachem.com/alkaline-buffer.php

I had heard it was potassium bicarbonate based…

 

I guess that source was wrong.

On 7/14/2024 at 6:51 PM, TanTann the fish man said:

Does Seachem Alkaline buffer affect PH at all?

Any time you raise KH, PH will rise as well unless an acid or acid buffer is added as well…

[Tony s]

On 7/14/2024 at 7:33 PM, Pepere said:

Any time you raise KH, PH will rise as well unless an acid or acid buffer is added as well…

This is one of the reasons I like to combine alkaline buffer with acid buffer. It not only allows you to target a certain ph. But it buffers you in to that range and prevents ph swings in either direction 

[Pepere]

On 7/14/2024 at 7:59 PM, Tony s said:

This is one of the reasons I like to combine alkaline buffer with acid buffer. It not only allows you to target a certain ph. But it buffers you in to that range and prevents ph swings in either direction

I have pretty much stopped dosing alkaline buffer.  My tap water is 1 degree KH and I do a 50% water change weekly and test ph a few hours after water change.  If I see it has dropped I will test KH.  I only ever so rarely have to add a tiny bit to raise kh to 1 degree.

In about a year on this schedule I haven't perceived any downside to it.

[Tony s]

On 7/14/2024 at 8:17 PM, Pepere said:

have pretty much stopped dosing alkaline buffer

Oh, absolutely. Nothing wrong with low kh. Or lower ph for that matter, as long as the keeper knows how to manage it. I, on the other hand, can’t actually use my water as is. Way too much iron and iron bacteria in the well. Watering grass here, you turn everything the water touches to a burnt red color. 

[Gastroplod]

Bicarb Soda from the supermarket cake/baking isle. it's about 8AUD for a 350g tub. One teaspoon raises the kh in my 250l tank about one degree, a quarter tsp raises it about one degree in my 65l tank, and just under a half tsp for my 90l tanks.

[TanTann the fish man]

On 7/14/2024 at 8:21 PM, Tony s said:

Oh, absolutely. Nothing wrong with low kh. Or lower ph for that matter, as long as the keeper knows how to manage it. I, on the other hand, can’t actually use my water as is. Way too much iron and iron bacteria in the well. Watering grass here, you turn everything the water touches to a burnt red color. 

I guess I never really thought of this. I do weekly water changes so I guess it's not a huge deal to have very low KH. I've just always been worried about it being so low and my PH crashing.

[Tony s]

On 7/15/2024 at 9:29 PM, TanTann the fish man said:

so I guess it's not a huge deal to have very low KH

as long as you stay on top of everything. low kh is okay. it allows you to keep a lower ph. with a lower ph you can keep fish I wouldn't try. Like apistos, german rams, discus, and wild caught south american. and allows you to breed fish I wouldn't be able to. I can keep most fish alive., but the fry need softer water than what I have. if I could actually use my water. I, on the other hand can easily keep live bearers, central americans, and africans. some very beautiful fish from both areas. 

But the key for you is going to be maintenance. If you let things slide (not that you're going to), you could get the ph crashes easily

[TanTann the fish man]

On 7/15/2024 at 9:43 PM, Tony s said:

as long as you stay on top of everything. low kh is okay. it allows you to keep a lower ph. with a lower ph you can keep fish I wouldn't try. Like apistos, german rams, discus, and wild caught south american. and allows you to breed fish I wouldn't be able to. I can keep most fish alive., but the fry need softer water than what I have. if I could actually use my water. I, on the other hand can easily keep live bearers, central americans, and africans. some very beautiful fish from both areas. 

But the key for you is going to be maintenance. If you let things slide (not that you're going to), you could get the ph crashes easily

Very great information. Thank you for taking the time to really explain things!