Maintaining a stable pH

[Ponyoryx]

Hello! New aquarist here. I have a 5gal fluval spec, moderately planted with 1 betta, 5 rasbora,  5 shrimp, and many snails. I do a water change (~20%) every 7-10 days, and  easy green and easy iron once weekly. My substrate is flourite black + rocks + sand.  I'm finding my parameters are staying stable except my pH. My tap water pH is 7.8 and I'm trying to keep my tank around 7.0-7.2. I have drift wood and Indian almond leaves (and love the tannins!), but I keep finding that after a few days and a water change, the pH creeps up to almost 7.6!! I'm noticing some crypt rot as a consequence, I believe. I have pH down drops, but I would prefer a more sustainable way to keep my pH low. I think adding a buffer like crushed coral will help with the fluctuations, but I fear it will hold my pH around 7.4-7.6. Any other suggestions? Am I doing something wrong?

Ammonia 0

Phosphate 0

Nitrate <20

Nitrite 0

GH 75ppm

KH 100ppm

Sorry I only know KH/GH in ppm because I have strips

 

[Stash Beardsley]

Just leave the pH where it is normally for your water. I have 7.6-7.8 pH also and I grow cryptocoryne wendtii. Thats the best way to maintain stable pH. 

Edited May 13, 2021 by Stash Beardsley

[gardenman]

To begin with, I doubt that your crypt rot is pH related. I have crypts growing in water that's got a pH around 8 with no issues. You really just want to keep your pH stable as much as anything. If it wants to be 7.6 then let it be 7.6. There's not that big of a difference between 7.2 and 7.6 so I wouldn't stress out about it. 

[Ponyoryx]

I guess I'm worri d it's harmful to the fish because I've been told they prefer a lower pH. If I can just keep it stable, then I will! I like having the almond leaves, so I will just keep a steady supply of them and my pH will land where it lands.

Thank you! 

[Mmiller2001]

Nice tank!

Don't use pH down drops; that's going to cause phosphate issues in the tank. In an inert substrate tank, maintaining a pH below 7.3 to 7.2 is going to be more difficult. I would go grab a GH/KH test kit and do some reading on KH. It's KH that determines pH. If KH rises, pH rises and vise versa. Also, CO2 and O2 concentrations will alter pH without a KH change. So, if you heavily aerate the tank, you would expect a pH increase. Also, a 1KH is just as stable as a 6KH, this is often confused. So, the TL/DR version, test KH, adjust KH to 3dKH and you will find yourself pretty close to 7.4 -7.3, go to 1dKH and you will be around 6.8 to 7.2. If you drop to a 1 KH, you will want to test KH weekly. 

[Patrick_G]

It’s a really nice looking tank! Someone correct me if I’m wrong but it looks like your crypts might still be converting to submerged growth. That might account for the rot. 

[Ponyoryx]

Thanks! The crypts are about 2 months old and did not melt at all when I planted them. 2 or 3 of the leaves have new large black spots, about 3-4mm in diameter. I just don't want it to get out of control so hopefully stabilizing my pH will help. I'm not home or I would send a closer pic. 

[CalmedByFish]

I still don't really understand the KH stuff above. (I'm new to doing this well.) 

When I recently asked a similar question, forum members told me that fish can adjust to a non-ideal pH much better than they can handle fluctuations, and said to not "chase" pH. So I stopped, letting my pH stay at the 7.8-8.0 that it is out of the tap. So far, so good. The only species we both have is snails, but I can at least tell you the snails are fine with it.

For the future, it was also suggested that I stick with choosing animals that are good with a higher pH, so I don't have to worry about it. I guess that would also apply to plant choices. 

[Eric R]

26 minutes ago, CalmedByFish said:

I still don't really understand the KH stuff above. (I'm new to doing this well.) 

When I recently asked a similar question, forum members told me that fish can adjust to a non-ideal pH much better than they can handle fluctuations, and said to not "chase" pH. So I stopped, letting my pH stay at the 7.8-8.0 that it is out of the tap. So far, so good. The only species we both have is snails, but I can at least tell you the snails are fine with it.

For the future, it was also suggested that I stick with choosing animals that are good with a higher pH, so I don't have to worry about it. I guess that would also apply to plant choices. 

[Hopefully this explanation below can help to demystify the issue a bit. My chemistry is okay, but not great, so someone (*cough* @DShelton *cough*) please correct me if any of this is wrong!]

KH is a measure of carbonate and bicarbonate ions in your water. It's the carbonate hardness, from the German word for carbonate. Along with GH (which stands for general hardness, and measures calcium, magnesium, and other ions in your water), this makes up the "hardness" in water. Acids are things that can add hydrogen ions to water (tannins have these, which is why leaves and wood can lower pH). Hydrogen ions are positively charged, and will bond with negative ions, like carbonate and bicarbonate. Thus, KH serves as a buffer, because it keeps acids from lowering your water's pH (which is a measure of how acidic or alkaline your water is, with smaller numbers below 7 being more acidic). This is why it's really difficult to lower the pH of your water if it has any hardness in it. Most people that have hard water and want to lower their pH use distilled water they buy from the store, or they buy an RO unit so that their water has no hardness in it, and thus no buffering capacity.

On the other hand, if you wanted to raise your ph or kh, you can use something like crushed coral or aragonite (which are mostly calcium carbonate) or baking soda (sodium bicarbonate) to add carbonates to your water, which increases carbonates (aka "buffering"), reduces H+ (hydrogen ions), and raises pH.

This is a good article with a little more information.

https://www.practicalfishkeeping.co.uk/features/frequently-asked-questions-on-lowering-hardness/

 

@Ponyoryx, I agree with the other posters, I don't think your hardness or pH seem so high that it should affect your crypts in the long term. They may just take a while to adjust to your water parameters. And I think your fish should be fine in those parameters.

Edited May 13, 2021 by Eric R

[Hobbit]

I third/fourth the advice to let your pH stays where it wants to. Your fish and plants will adjust over time. The instability of trying to get your pH to stay down will be worse for the fish and plants than a stable pH that’s a tad outside of their norm. 👍

If you really want to keep a lower pH, @Mmiller2001 has good advice about where your KH needs to be. To achieve this low of a KH and keep it there, you may need to water change with reverse osmosis water or distilled water that you can buy from the grocery store.

Also know that over time, your plants will pull nutrients out of the water and lower your pH naturally. Assuming you’re not just replacing them every time you water change. 😅

But again, I wouldn’t worry about the exact pH. Keeping it stable is most important.

And like others have said, your tank looks beautiful!

[Ponyoryx]

Thanks everyone for the great advice!! I feel much less stressed about this and will focus on a stable pH. 

[CalmedByFish]

3 hours ago, Eric R said:

KH serves as a buffer, because it keeps acids from lowering your water's pH

So increasing KH doesn't directly raise the pH? It just prevents other things from *lowering* the pH? 

[Hobbit]

@CalmedByFish it does directly raise the pH. It *also* keeps other things from lowering the pH. Buffers are weird and wonderful!

[Mmiller2001]

13 minutes ago, CalmedByFish said:

So increasing KH doesn't directly raise the pH? It just prevents other things from *lowering* the pH? 

Increasing KH raises pH.

[CalmedByFish]

@Hobbit  High school chemistry was either the 1st or 2nd class in school that I could barely pass. 🙄 

[CalmedByFish]

2 minutes ago, CalmedByFish said:

@Hobbit  High school chemistry was either the 1st or 2nd class in school that I could barely pass. 🙄 

Edit: And now I see you were a science teacher! LOL Good luck with ME. Pff! 

Edit #2: Apparently I've also lost the ability to post correctly. Whatever. I'm off to my non-nerm life for now. 

Edited May 13, 2021 by CalmedByFish

[Mmiller2001]

3 minutes ago, CalmedByFish said:

@Hobbit  High school chemistry was either the 1st or 2nd class in school that I could barely pass. 🙄 

Don't worry about KH chemistry, just have a basic understanding of what it does. It keeps pH in a relative range and holds it there.

Higher KH, higher pH ranges

Lower KH, lower pH ranges.

Edited May 13, 2021 by Mmiller2001

[Mmiller2001]

https://fishlab.com/aquarium-kh/

Good article for beginners.

[Hobbit]

@CalmedByFish not to worry! I’m sure you can learn a lot more now with an adult brain, plenty of time, and a vested interest in the subject, instead of in a classroom as a teen with no reason to care, being rushed to learn it in 40 minutes. 😉 But the general principle @Mmiller2001 laid out will work just fine, too.

@Irene also did a great video about pH, KH, and GH. 

 

[Eric R]

40 minutes ago, CalmedByFish said:

So increasing KH doesn't directly raise the pH? It just prevents other things from *lowering* the pH? 

[I got a like from @DShelton before, so I'm going to assume that my previous post was at least mostly correct. I'll make an attempt to explain further, but please someone correct me if I'm wrong!]

pH is a measure of the amount of hydrogen ions (H+) in a solution (in this case, water), when there is more H+, it's more acidic, when there is less H+ it's less acidic (more alkaline).

I think most of us know that water is H2O.  But some of that hydrogen and oxygen is present as ions in the water, like H+ (hydrogen ion), OH- (hydroxide ion), or even H3O+ (hydronium). You can also think of pH as the ratio of hydrogen ions to hydroxide ions.

When you have a pH of exactly 7, the hydrogen ions (H+) and hydroxide ions (OH-) are equal. When you have a pH of 0, you have pretty much only hydrogen ions, and when you have a pH of 14, you have pretty much only hydroxide ions.

This is why adding carbonates, like calcium carbonate or sodium bicarbonate (baking soda) raises KH and pH in our aquariums, since they have some amount of free hydrogen ions still.

I thought that this was an interesting table that shows the relationship between the amount of hydrogen and hydroxide ions in water and its pH. [Source]

[tonyjuliano]

6 hours ago, Mmiller2001 said:

1KH is just as stable as a 6KH,

Uh....  no.

The pH in an environment with a carbonate hardness level of 1dKH is MUCH more likely to swing than if the measurement was 6dKH.

If your carbonate hardness is less than 3, bad things are waiting to happen.

[Mmiller2001]

22 minutes ago, tonyjuliano said:

Uh....  no.

The pH in an environment with a carbonate hardness level of 1dKH is MUCH more likely to swing than if the measurement was 6dKH.

If your carbonate hardness is less than 3, bad things are waiting to happen.

Really? My KH is 1.5dGH, what bad things am I missing?

This tank, has a 0KH, what bad things are you referring to?

 

[tonyjuliano]

17 minutes ago, Mmiller2001 said:

This tank, has a 0KH, what bad things are you referring to?

I’m referring to the fact that your tank with no carbonate hardness is an accident waiting to happen. If any amount of acidic material is introduced into that environment, the pH is likely to swing - rapidly - killing most fish quicker than you can say “time to head down to the fish store”.

The acid source doesn’t even have to be anything you introduce yourself.  Nitrite and nitrate are both acidic.

If it hasn’t happened yet, consider yourself fortunate.

The title of this thread is “Maintaining Stable PH”.  Zero carbonate hardness is just about the worst thing you can have if pH stability is the goal.

 

Edited May 13, 2021 by tonyjuliano

[Mmiller2001]

49 minutes ago, tonyjuliano said:

I’m referring to the fact that your tank with no carbonate hardness is an accident waiting to happen. If any amount of acidic material is introduced into that environment, the pH is likely to swing - rapidly - killing most fish quicker than you can say “time to head down to the fish store”.

The acid source doesn’t even have to be anything you introduce yourself.  Nitrite and nitrate are both acidic.

If it hasn’t happened yet, consider yourself fortunate.

The title of this thread is “Maintaining Stable PH”.  Zero carbonate hardness is just about the worst thing you can have if pH stability is the goal.

 

My Nitrates are constantly 30ppm and my pH swings from 7.3 to 5.9 every single day. I'm just not sure what you are referring to. 

 

[tonyjuliano]

3 minutes ago, Mmiller2001 said:

My Nitrates are constantly 30ppm and my pH swings from 7.3 to 5.9 every single day. I'm just not sure what you are referring to. 

Okay...

So it appears that this isn’t even a serious (or rational) discussion.

I don’t even know how to respond the the quote above.