kH confusion

[Tonik]

Good morning all!  Recently I watched one of the Coop's video's where Cory was talking about why we do water changes, and he mentioned "fear" as one of the reasons. That resonated with me because since starting this hobby in July 2020, that has been my motivation.  Anyway, after watching that, I decided to get some test strips and stop fanatically testing my water every two days and to try to enjoy the fish more than stressing about parameters.  It was an anxious time, but I finally learned that the ecosystem in my 29 is actually doing really well without me messing with it.  I learned that I can wait to change water for about two weeks instead of twice a week - that was a feat of willpower.😃

But..... I have researched and watched videos about the relationship between pH, gH, and kH, and read the posts on the Forum that are related, but I still have some questions... My main tank is 29gal with sponge filters and it has been set up for about 6 -7 weeks, using media from an established tank.  It is heavily planted (and has cholla wood and various river rocks which I have had since July) with a substrate of eco-complete and a black sand cap.  I use Easy Green 1 time per week and root tabs once at the start and once last week - the corys and swordtails dug them up though.  I have a bunch of hitchhiker snails, 3 Mystery snails, and 4-5 Amano shrimp.  I also have 5 Panda and 6 Pygmy corydoras,  6 Black Neon and 10 Ember tetras, and three Swordtails, 2 F,1 M.   It seems like a lot of fish, but I had to consolidate two tanks on the fly, plus they are doing great. My numbers are regularly 0-ammonia, 0 -nitrite, ~20 - nitrate, and pH of 7.8 - 8.0.  My water is hard, GH of 180-300, and at first, the KH was around 120 (these values are from test strips; I've a kit on order).  Within the last week or so the KH has been testing at around 40.  Why has it fallen?  Is it because I'm changing water less frequently and thus replenishing the minerals less frequently?  The pH and GH are the same as before though.  Are the plants, snails, shrimp and/or fish depleting it, and if so, should I use Wonder Shell or crushed coral.  I've read that crushed coral raises pH and hardness, and my water is already very hard and the pH is  quite high. Will messing with the KH affect those parameters?  If I leave it alone, will my shrimp and snails suffer?  I've read both to do something and to do nothing.  If I'm adding something, how much should I add and how often?  I should get my Gh and KH test kit this week and then will have more accurate numbers. 

[Alesha]

@Tonik, I deal with almost the exact same scenario with my tanks, IF they don't have crushed coral. I hesitated about doing the coral, too, but it hasn't raised my GH as I thought it would. It does however seem to stabilize my kH. I also have a wondershell in every tank & the giant one disappears in about  5-6 weeks, so I know my water is missing something. 

I will be really interested to see the answers you get from the experts here. It's something I've tried to research/study in my own too, & just can't find the key to it (or the key to my understanding it,  may be more likely the truth!)😉

[Tonik]

12 minutes ago, akconklin said:

@Tonik, I deal with almost the exact same scenario with my tanks, IF they don't have crushed coral. I hesitated about doing the coral, too, but it hasn't raised my GH as I thought it would. It does however seem to stabilize my kH. I also have a wondershell in every tank & the giant one disappears in about  5-6 weeks, so I know my water is missing something. 

I will be really interested to see the answers you get from the experts here. It's something I've tried to research/study in my own too, & just can't find the key to it (or the key to my understanding it,  may be more likely the truth!)😉

That's exactly right... I feel that I'm going in circles with the understanding if it!  I am glad to hear that the coral didn't change GH.  It is out of stock at the Coop right now, but I may try some Wondershell.  I worry most about my shrimpies!

[Alesha]

6 minutes ago, Tonik said:

 I may try some Wondershell.  I worry most about my shrimpies!

I have 1-2 shrimp sitting on the Wondershell all the time!  So, there must be a reason. Someone will wander over shortly & give us some clarity. 👍

[Daniel]

1 hour ago, Tonik said:

 It seems like a lot of fish, but I had to consolidate two tanks on the fly, plus they are doing great. My numbers are regularly 0-ammonia, 0 -nitrite, ~20 - nitrate, and pH of 7.8 - 8.0.  My water is hard, GH of 180-300, and at first, the KH was around 120 (these values are from test strips; I've a kit on order).  Within the last week or so the KH has been testing at around 40.  Why has it fallen?  Is it because I'm changing water less frequently and thus replenishing the minerals less frequently?  The pH and GH are the same as before though.  

It is tempting to chase numbers, especially easy to measure numbers. But in the end those numbers you are manipulating are just a couple of data points of a very complex ecosystem. Resist the temptation to chase numbers.

The best indicator, better than any test, liquid or strip is how are your fish and plants doing. It sounds like you have a happy tank. So it is very likely you have little to worry about.

I usually look for a strategy that involves doing nothing. Yes I am extremely lazy, but there are other reasons too. Sometimes the less you do, the easier it is to maintain stability and stability is a worthy goal in its own right.

But I also suspect your instincts are right in that the carbonate hardness (KH) is buffering the pH in your aquarium. It is possible that the less frequent water changes contribute to the lowering of your KH. If that is true, then there is a 'sink' in the aquarium that is consuming or utilizing the carbonate ions.

All that being said, I am just about to contradict myself just a little because I love experiments. How do we learn otherwise?

You seem like a measuring type person. I would love to know what happens were you to add either crushed coral or Wondershell. Wondershells and crushed coral are such mild interventions that I believe there is very little downside in using them. My hypothesis is that you pH would not go up, but your KH might increase a little.

It sounds like you may already had read this, but others may benefit from this very helpful blog post from the Co-Op.

The Fish Keeper’s Guide to pH, GH, and KH

WWW.AQUARIUMCOOP.COM

---

pH, GH, and KH are terms commonly used in water chemistry, but there is a lot of confusion surrounding them in the freshwater aquarium hobby. This practical guide for beginners explains what these parameters mean, when...

 

 

[Tonik]

6 minutes ago, Daniel said:

You seem like a measuring type person. I would love to know what happens were to add either crushed coral or Wondershell. Wondershells and crushed coral are such mild interventions that I believe there is very little downside in using them. My hypothesis is that you pH would not go up, but your KH might increase a little.

I do really like the measuring aspect; I think it reinforces the feeling/illusion of being in control, plus who doesn't love lining up test tubes and watching the reactions! lol.    I will try the Wondershell and I should be able to measure the changes more accurately with the KH test kit that should arrive this week.  I'm glad to know that either the WS or the coral would be mild interventions; I think that is what I most wanted to know!    

 

[Aqua junky]

I can read this topic over and over but it just wont sink in!  I have the api liquid test bottles for CH and KH and dont really understand either of them. My plants look alright. They are newer plants so I'm blaming that on melting.  My fish are all doing good. I try to keep my Nitrates around 40ppm Nitrites are usually 0 I can tell you how many drops my ch and kh took to change color but the actual number chart confuses the shit out of me

[Daniel]

47 minutes ago, Mclovin said:

I can read this topic over and over but it just wont sink in!

It is all about the ions, that is a charged (or electrically non-neutral) atom. KH measures carbonate and bicarbonate (CO^2-₃and HCO^-₃) ions. GH measures calcium (Ca²⁺) and magnesium (Mg²⁺) ions. pH measures free hydrogen ions (H⁺).

So we are measuring a carbon compound, minerals, and protons (or a little broken off piece of water).

Most of this never matters too much. But because the carbonate ions and the protons are somewhat attracted to each other they tend to stabilize each other in a good way. Also, shrimp really need the carbonate ions to help build their exoskeletons.

That leaves the calcium and magnesium. Calcium helps transmit messages in living things and is super helpful with enzymes, and enzymes make the world go around. Magnesium is important photosynthesis, DNA synthesis and of course enzymes again. Some fish like more calcium and magnesium, some like less.

If you never measured any of this, chances are you would be just as well off, but we can so we do.

 

[Tonik]

UPDATE: I got my test kit on Tuesday and did the KH and GH tests.  KH was 3 drops/0-50 ppm.  GH was 8 drops/140-200 ppm. 
wednesday: added large Wondershell.  Sunday retested: KH-4 drops/50-100 ppm  GH-8 drops/140-200 ppm 
 

A slight increase in KH and no change in GH.  But, on Friday I found a tiny panda Cory hiding out in the java moss.  That means the fish are reproducing which is a good sign of a healthy tank!  (Which is what you guys already said! 😊