Ph, Kh, and Gh- Preferences and techniques

[schmofam]

Hey All,

I have a couple of questions regarding PH, KH, and GH. 
First, my water parameters-

Coming out of my tap here in Colorado:
PH ~7.6
GH ~ 150
KH ~40

From the aquarium:
PH ~7.0 - 72
GH ~ 150
KH ~0

I have recently set up this newly planted 20-gallon tank. I have moved all of the plants over from my previous 10-gallon tank. It has a Fluval Stratum substrait.

There are 17 fish total—10 Neon Tetras, 4 Platys, and 3 Guppies with a Narite and a Mystery Snail. I have a sponge filter and a hang-on back filter. The hang-on back is because I put crushed coral as part of the media to raise the Kh. However, perhaps because of how big the tank is or how small the filter is, I do not see any increase. Because the substrate is black I do not want to spread crushed coral and ruin the look.

I do a weekly water change of ~10-15%.

I believe the pH should slowly be increased from what I have read. Optimally to ~ 7.5. I do know quickly adjusting it can be harmful to the fish. My ideas: more/bigger water changes. Adding different media to the filter besides crushed coral. I do have Ph Up from API that I have been using but don't want to eternally rely on it.

My questions:
1. Opinions on my target water param values?
2. Other ideas on how to raise the Kh and Ph given my constraints?

Thanks!

Edited September 28, 2023 by schmofam

[Mmiller2001]

Aqua soil being used?

[AllFishNoBrakes]

Yo! Normally I don’t really comment on pH/KH/GH type questions, but then I read you’re in CO and I am too! I’ll tell you what I do in my 14 tanks that have been running for 3+ years. 
 

I do a whole lot of nothing. No crushed coral, no Seachem alkalinity or stability, and definitely no API up/down. 
 

My tanks run even a little softer than yours. High 6’s on the pH, 0 to very little KH, and I have no clue on the GH. 75-120 TDS (which is basically useless as I have no clue what the “stuff” actually is, but confirmed my water is very soft). 
 

I personally think you’re on the right track with bigger water changes. Knowing how soft our water is, and not wanting to mess with it, I do 20-30% water changes every week. Consistency is the key for me and has worked out very well. Knowing our water doesn’t have a lot of minerals in it I want to replenish a decent amount, and I do that with slightly bigger water changes on a weekly basis. I also made the decision to not play with fish that I know have no chance in our natural water. No African Cichlids for me that want high pH hard water. Simply doesn’t make sense to me to try to “make” water. Instead, I play with what I think will do well with our natural water. 
 

Weekly water changes, water conditioner, and Easy Green for me and it’s been very successful with a lot of different fish, plants, and inverts. 
 

Feel free to message me on the side if you wanna chat more from another person located in CO!!

Edited September 28, 2023 by AllFishNoBrakes

[schmofam]

On 9/28/2023 at 2:38 PM, Mmiller2001 said:

Aqua soil being used?

I am using Fluval Stratum if that answers your question regarding soil.

[Mmiller2001]

On 9/28/2023 at 3:16 PM, schmofam said:

I am using Fluval Stratum if that answers your question regarding soil.

So that will pull the KH out of the water.

[AllFishNoBrakes]

On 9/28/2023 at 3:18 PM, Mmiller2001 said:

So that will pull the KH out of the water.

In order to eventually drop the pH, right?

[Mmiller2001]

On 9/28/2023 at 3:31 PM, AllFishNoBrakes said:

In order to eventually drop the pH, right?

Any reduction in KH will lower pH to a point.

[AllFishNoBrakes]

On 9/28/2023 at 3:55 PM, Mmiller2001 said:

Any reduction in KH will lower pH to a point.

For sure. I’ve never personally used it as like I said I already have low pH, soft water, with little to no buffer. 
 

I guess my general understanding is that kH is essentially insurance against a massive pH drop. I thought as long as you had some kH, the pH wouldn’t drastically drop. 
 

The incremental “as kH lowers, so will pH to an extent” makes sense. I just wanna learn as I have very little, or no kH in my water, and my pH doesn’t really move. Even with my blackwater tanks where I thought for sure I’d see some movement. 

Edited September 28, 2023 by AllFishNoBrakes

[Biotope Biologist]

Leave your water as is. Colorado water has tons of minerals that are beneficial to plants and fish alike. If it starts getting too limescale-y you can always soften the water before adding. 
 

But generally your water should be find unless you’re chasing certain biotopes and sensitive animals/plants.

[nabokovfan87]

On 9/28/2023 at 12:50 PM, schmofam said:

2. Other ideas on how to raise the Kh and Ph given my constraints?

I have the same issue / reasoning for my tank and I use Seachem Alkalinity buffer products. 

[Galabar]

So, it looks like your soil is "eating" the KH.  At some point, that soil will stop "working," and the KH in your tap water will be plenty.  However, until that happens, you should consider something like (as nabokovfan87 mentioned) Seachem Alkalinity.  You don't need a high KH, just a non-zero KH (as KH is needed for converting ammonia to nitrate).

[Mmiller2001]

On 9/28/2023 at 3:58 PM, AllFishNoBrakes said:

For sure. I’ve never personally used it as like I said I already have low pH, soft water, with little to no buffer. 
 

I guess my general understanding is that kH is essentially insurance against a massive pH drop. I thought as long as you had some kH, the pH wouldn’t drastically drop. 
 

The incremental “as kH lowers, so will pH to an extent” makes sense. I just wanna learn as I have very little, or no kH in my water, and my pH doesn’t really move. Even with my blackwater tanks where I thought for sure I’d see some movement. 

Indeed pH drops as KH lowers, but even at 0KH, there’s a lower boundary that pH will not exceed without extreme influences.

On 9/28/2023 at 8:01 PM, Galabar said:

You don't need a high KH, just a non-zero KH (as KH is needed for converting ammonia to nitrate

Nothing could be further from the truth. This thinking isn’t your fault, but it’s an on going misconception in our hobby 

Heres my tank at 0dKH

 

[Galabar]

Your tank isn't 0 dKH.  You'd need equipment that you probably don't have to measure that. 🙂

https://www.cwea.org/news/how-alkalinity-affects-nitrification/

Quote

How much alkalinity is needed?

To nitrify, alkalinity levels should be at least eight times the concentration of ammonia in wastewater. This value may be higher for untreated wastewater with higher-than-usual influent ammonia concentrations. The theoretical reaction shows that approximately 7.14 mg of alkalinity (as CaCO3) is consumed for every milligram of ammonia oxidized. A rule of thumb is an 8-to-1 ratio of alkalinity to ammonia. Inadequate alkalinity could result in incomplete nitrification and depressed pH values in the facility. 

https://www.epa.gov/sites/default/files/2015-09/documents/nitrification_1.pdf

Quote

3.1.3 pH and Alkalinity Bulk water pH value is an important factor in nitrification activity for two reasons. First, a reduction of total alkalinity may accompany nitrification because a significant amount of bicarbonate is consumed in the conversion of ammonia to nitrite. A model developed by Gujer and Jenkins (1974) indicates that 8.64 mg/L of bicarbonate (HCO3 - ) will be utilized for each mg/L of ammonia-nitrogen oxidized

Edited September 29, 2023 by Galabar

[Mmiller2001]

On 9/28/2023 at 9:41 PM, Galabar said:

Your tank isn't 0 dKH.  You'd need equipment that you probably don't have to measure that. 🙂

https://www.cwea.org/news/how-alkalinity-affects-nitrification/

https://www.epa.gov/sites/default/files/2015-09/documents/nitrification_1.pdf

Just need a good RO/DI system. And indeed this tank is at 0dKH. In fact , my pH goes as low as 4.8 and I have the equipment to verify my claims.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1489657/?fbclid=IwAR25x7nAnd5ECTXbVZwPcG4rVudi5gkaRfABkeAHCO2YuaqhVQ0QhBJQkRU
 

 

[Galabar]

On 9/28/2023 at 10:36 PM, Mmiller2001 said:

Just need a good RO/DI system. And indeed this tank is at 0dKH. In fact , my pH goes as low as 4.8 and I have the equipment to verify my claims.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1489657/?fbclid=IwAR25x7nAnd5ECTXbVZwPcG4rVudi5gkaRfABkeAHCO2YuaqhVQ0QhBJQkRU
 

 

How did you measure your "0 dKH?"

...and from that article:

Quote

 The system was supplied with bicarbonate in stoichiometric amounts to the nitrification rate (60).

 

Edited September 29, 2023 by Galabar

[Mmiller2001]

Production grade TDS meter. 

On 9/28/2023 at 11:38 PM, Galabar said:

How did you measure your "0 dKH?"

 

[Galabar]

What does your TDS meter measure? You realize that TDS meters measure all organic and inorganic materials (metal, salts, etc.).

Does your TDS meter measure 0 (0 KH, 0 GH, no organic or inorganic molecules in your fish tank)? 🙂

p.s.  It's a beautiful tank, by the way. 🙂

 

 

Edited September 29, 2023 by Galabar

[Mmiller2001]

On 9/28/2023 at 11:53 PM, Galabar said:

What does your TDS meter measure? You realize that TDS meters measure all organic and inorganic materials (metal, salts, etc.).

Does your TDS meter measure 0 (0 KH, 0 GH, no organic or inorganic molecules in your fish tank)? 🙂

 

 

Yes, my RO/DI water is 0 TDS and I add no carbonates to my water.

[Galabar]

On 9/28/2023 at 10:57 PM, Mmiller2001 said:

Yes, my RO/DI water is 0 TDS and I add no carbonates to my water.

...and no food, fertilizer, or anything else?

What does the TDS measure in your tank? 🙂

Edited September 29, 2023 by Galabar

[Mmiller2001]

On 9/28/2023 at 11:57 PM, Galabar said:

...and no food, fertilizer, or anything else?

Of course, and non of those contain carbonates or bicarbonates that I’m aware of.

The tank TDS runs around 170, non of that is KH. I simply don’t add carbonates or bicarbonates.

Edited September 29, 2023 by Mmiller2001

[Galabar]

On 9/28/2023 at 10:58 PM, Mmiller2001 said:

Of course, and non of those contain carbonates or bicarbonates that I’m aware of.

So, your original statement that your tank has "0 dKH" is based on you using RO water and not adding any carbonates?  I just want to make sure I'm understanding what you said.

You haven't tested the actual tank water with something accurate enough to show 0 dKH and you add various things including food and fertilize to your tank.

I'll ask: are you sticking to the 0 dKH in your tank statement (and also that nitrification needing carbonates is "an on going misconception in our hobby")? 🙂

Edited September 29, 2023 by Galabar

[Mmiller2001]

On 9/29/2023 at 12:05 AM, Galabar said:

So, your original statement that your tank has "0 dKH" is based on you using RO water and not adding any carbonates?  I just want to make sure I'm understanding what you said.

You haven't tested the actual tank water with something accurate enough to show 0 dKH and you add various things including food and fertilize to your tank.

I'll ask: are you sticking to the 0 dKH in your tank statement? 🙂

100% . Unless carbonates and bicarbonates magically appear in the tank. Please educate me if I’m missing something. I have tested the tank with the hobbyist level KH kit at 20ml samples per drop and still 0KH. 
 

seriously educate me where I’m wrong.

[Galabar]

On 9/28/2023 at 11:10 PM, Mmiller2001 said:

...hobbyist level KH kit at 20ml samples per drop and still 0KH...

When you place one drop in a hobbyist kit test tube (like API), and the color changes, you are measuring < 1 dKH, not 0 dKH.

So, you can say that your aquarium has < 1 dKH.

Like I said above, a low KH is Ok, but 0 KH (0.0 KH) is not.

Take a look at the various articles/studies above, including the one that you posted.  They all state that carbonates are consumed during nitrification.  You need carbonates for nitrification.  If your tank truly had 0 dKH (it doesn't) there would be no nitrification.

Now, to be pedantic, when you said that your tank had 0 dKH, you could have meant that it had < 0.5 dKH (not 0.0 dKH).  However, I don't think that's what you meant.

Again, though, that it a really nice tank.

One thing that confuses me.  Rainbow fish usually like a higher KH (higher than 0.5) and a pH of at least 7.5.  Why do you want to keep such a low pH?

Edited September 29, 2023 by Galabar

[Mmiller2001]

On 9/29/2023 at 12:17 AM, Galabar said:

When you place one drop in a hobbyist kit test tube (like API), and the color changes, you are measuring < 1 dKH, not 0 dKH.

So, you can say that your aquarium has < 1 dKH.

Like I said above, a low KH is Ok, but 0 KH is not.

Take a look at the various articles/studies above, including the one that you posted.  They all state that carbonates are consumed during nitrification.  You need carbonates for nitrification.  If your tank truly had 0 dKH (it doesn't) there would be no nitrification.

Now, to be pedantic, when you said that your tank had 0 dKH, you could have meant that it had < 0.5 dKH (not 0.0 dKH).  However, I don't think that's what you meant.

Again, though, that it a really nice tank.

One thing that confuses me.  Rainbow fish usually like a higher KH and a pH of at least 7.5.  Why do you want to keep such a low pH?

I digress, starting from 0TDS water and no addition of carbonates or bicarbonates, how would they show up in the tank water? 

 

On 9/29/2023 at 12:17 AM, Galabar said:

One thing that confuses me.  Rainbow fish usually like a higher KH and a pH of at least 7.5.  Why do you want to keep such a low pH?

Plants come first in my tank and pH is irrelevant from my experience. It’s also more stable to run 0KH versus trying to maintain any amount of KH (at a consistent level) long term.

[Galabar]

On 9/28/2023 at 11:29 PM, Mmiller2001 said:

I digress, starting from 0TDS water and no addition of carbonates or bicarbonates, how would they show up in the tank water? 

 

Plants come first in my tank and pH is irrelevant from my experience. It’s also more stable to run 0KH versus trying to maintain any amount of KH (at a consistent level) long term.

https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/krill

Quote

 

Biological Salts and Ligand Complexes

The major insoluble calcium salts found in organisms are the fluoride (in krill), carbonates (in shells in at least three allotropic forms), phosphates (in bone), and oxalates (in many plants). 

 

Also, calcium is an essential plant nutrient and your plants are doing very well... 🙂

So, whatever you are doing you are adding enough nutrients, minerals, etc. (calcium, magnesium, including carbonate salts) to make a very healthy tank.

Edited September 29, 2023 by Galabar