PH and KH Dropping All the Time

trinity28

I need help with my pH situation. A few weeks ago I discovered that all of my tanks had a pH of less than 6. Hence, the nitrogen cycle had stalled. I posted about it here and got some advice, but I still don’t know what is causing the pH drops. Every time I do a water change the pH will go up to around 7, only to drop back down again within a few days. The KH also drops to pretty much zero, or 1 at the most.

My tap water comes from Lake Michigan and has a pH of 7.8, a GH of 10, and a KH of 6. From what I understand, my water should have no problem maintaining its pH. And yet it cannot, in every tank and after every water change. I do water changes once a week and do about 30-40%.

I’ve never heard of anyone in my area having this problem, and I’m sort of at my wit’s end. I bought some aragonite and added it to a bucket full of tap water. It raised the pH to over 8 overnight. I added some to one tank as a trial but it doesn’t seem to be making much of a difference.

Does anyone have any thoughts as to what could possibly going on? I’m desperate here. Thanks!
 

Treestone

I would've said OTS but it happening to all of your tanks at the same time is very weird. I remember having a similar issue on one tank for no apparent reason and ended up restarting it, now it works a treat. Good luck
 
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Sorg67

I have never heard of KH dropping that fast.

Maybe try water changes twice a week for a while. It seems plausible that KH could have been depleted over time if water changes were not sufficient. If you do your water changes twice a week, you might build the KH up over time. Seems your source water ought to be sufficient.

If your KH is low, I would be cautious about doing more than 30 to 40% water changes since it may cause a shocking change in parameters. But if you do changes twice a week KH should build up. If KH builds up pH will stabilize.

After you build your KH up, perhaps you will need larger weekly water changes. I would just be careful about big water changes if your tank water has much lower KH than your source water.

I might even keep it to 25%. Maybe even three times a week. But I am just speculating. Don’t really know. Seems the two possibilities are something is eating a lot of KH or water changes are insufficient.

Chanyi do you know of anything that consumes KH like that?
 
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AmnScott

Your Carbonate Hardness (dKH) is way low, it should be well above 0/1. That is why your pH keeps dropping. Carbonate Hardness acts as a buffer, by neutralizing the acidic properties in the tank. But I am not sure why your dKH is so low, if your tap water has a KH of 6?

I would look into adding in an Alkaline buffer. I have never had this specific issue, but Seachem makes a good Alkaline buffer from what I hear. Also, crushed coral can help raise pH.

Once your dKH is where it should be, you will have higher, more consistent, pH levels. As recommended above, I would do water changes a little more often, coupled with an Alkaline buffer.

I know bacteria uses up some KH, but that doesn't explain why it is so low.
 
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trinity28

Your Carbonate Hardness (dKH) is way low, it should be well above 0/1. That is why your pH keeps dropping. Carbonate Hardness acts as a buffer, by neutralizing the acidic properties in the tank. But I am not sure why your dKH is so low, if your tap water has a KH of 6?

I would look into adding in an Alkaline buffer. I have never had this specific issue, but Seachem makes a good Alkaline buffer from what I hear. Also, crushed coral can help raise pH.

Once your dKH is where it should be, you will have higher, more consistent, pH levels. As recommended above, I would do water changes a little more often, coupled with an Alkaline buffer.

I know bacteria uses up some KH, but that doesn't explain why it is so low.
Yeah, I know the KH is way too low and that that’s why the pH is low. What I’m trying to determine is why, and why it keeps lowering after water changes since my tap water should be just fine. As I mentioned I’m trying aragonite but not sure if it’s not making a difference or if I’m not using enough. I’m trying to add it really really slowly because if I get the pH back up and the cycle starts again my fish are not going to fare well...
 
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AmnScott

Yeah, I know the KH is way too low and that that’s why the pH is low. What I’m trying to determine is why, and why it keeps lowering after water changes since my tap water should be just fine. As I mentioned I’m trying aragonite but not sure if it’s not making a difference or if I’m not using enough. I’m trying to add it really really slowly because if I get the pH back up and the cycle starts again my fish are not going to fare well...

Do you have any plants in the tank? I know that plants can sometimes leech carbonates from the water if they are not getting other nutrients.
 
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Chanyi

What is your substrate?
 
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trinity28

I do have plants but in some tanks I only have one or two. All of my substrate is inert, either sand or gravel.
 
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LightBrownPillow

I'm inclined to echo the focus on really getting your KH up and stable so you have a good buffer, seems like that's been pretty well covered. Such a rapid KH drop is very odd. Just to spitball some other ideas:
  • Do you have a lot of inverts who could be using up minerals in shell growth? Not normally an issue but one possible drain on KH
  • Any decorations which might be softening the water? Wood in particular, but maybe some plastics which aren't so safe?
  • Any sort of airborne fumes/particles your tanks might be exposed to which are acidic?
  • You might do an experiment of keeping a small glass container of tap water and testing it over a few days. If the hardness changes just from sitting in the empty container, something is going in the water itself & not just your tanks. I'd contact your water company and ask if they have ideas.
Hope you can figure this out soon!
 
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trinity28

I'm inclined to echo the focus on really getting your KH up and stable so you have a good buffer, seems like that's been pretty well covered. Such a rapid KH drop is very odd. Just to spitball some other ideas:
  • Do you have a lot of inverts who could be using up minerals in shell growth? Not normally an issue but one possible drain on KH
  • Any decorations which might be softening the water? Wood in particular, but maybe some plastics which aren't so safe?
  • Any sort of airborne fumes/particles your tanks might be exposed to which are acidic?
  • You might do an experiment of keeping a small glass container of tap water and testing it over a few days. If the hardness changes just from sitting in the empty container, something is going in the water itself & not just your tanks. I'd contact your water company and ask if they have ideas.
Hope you can figure this out soon!
Thanks for the reply! I do have ramshorn snails in every tank (and quite a few because their population exploded). Could this possibly be the issue? I have cherry shrimp in one tank. I have driftwood but not in every tank so I don’t think it’s that. I don’t think there are any fumes, especially since not all of my tank are in the same area. I will try the water experiment, thanks for the idea!
 
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LightBrownPillow

Thanks for the reply! I do have ramshorn snails in every tank (and quite a few because their population exploded). Could this possibly be the issue? I have cherry shrimp in one tank. I have driftwood but not in every tank so I don’t think it’s that. I don’t think there are any fumes, especially since not all of my tank are in the same area. I will try the water experiment, thanks for the idea!


I'm not confident a bunch of snails will cause the issue, but certainly they will draw minerals. Maybe you can move most of them to an isolated tank and see if that has any affect on water parameters?
 
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Chanyi

What are you adding to the water during a water change?
What decor / hardscape do you have?
What media are you running in your filter?
Are your test kits expired? How are you testing?
 
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trinity28

What are you adding to the water during a water change?
What decor / hardscape do you have?
What media are you running in your filter?
Are your test kits expired? How are you testing?
During water changes I only add Prime.
I have mostly driftwood as décor. No rocks. The rest is just plants or fake plants.
I run sponge filters in all of my tanks.
Test kits are not expired. The master kit I have is a few months old. The GH and KH test is a few weeks old. I have tested pH with both the test kit and a digital pH meter.
 
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Chanyi

Do you have access to a municipal water report?
 
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Wrench

Do you have any air stones in the tanks?
What is your filter media consisting of?
How big are the pieces of wood and the tanks they are in?
If your source water is above 7 and your dipping below 6 something in the tank is causing it.
Have you tried leaving the source water in a bucket overnight and checking ph then after it gives off?
How long has the plastic decor been in the tank?
Even though food grade is safe over time any matter will break down and alter especially in water....plastic may be leeching into your water,but you would have to see what ph is at after a gas off overnight from source...if it gases off and rest below 6 then you can try and raise it with shells and crushed coral I believe.
 
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trinity28

Do you have access to a municipal water report?
Yes, I do. Is there something I should look for on it?
 
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trinity28

Do you have any air stones in the tanks?
What is your filter media consisting of?
How big are the pieces of wood and the tanks they are in?
If your source water is above 7 and your dipping below 6 something in the tank is causing it.
Have you tried leaving the source water in a bucket overnight and checking ph then after it gives off?
How long has the plastic decor been in the tank?
Even though food grade is safe over time any matter will break down and alter especially in water....plastic may be leeching into your water,but you would have to see what ph is at after a gas off overnight from source...if it gases off and rest below 6 then you can try and raise it with shells and crushed coral I believe.
No airstones.
I only have sponge filters.
Not all my tanks have wood, but my biggest pieces are max two feet long with a two or three inch diameter. The largest pieces are in my 29 gallon.
I set up a bucket of tap water yesterday and will test it again tonight to see if it has changed.
I don’t have much plastic decor - just a few plastic plants. I have two ceramic pieces of decor in two separate tanks. I’ve always had these plants and decor in the tanks and some have been in other tanks in the past.

One thing I’ve thought of: is it possible overfeeding has caused this? I am certain I feed too much - I have a problem with it and feel like I’m starving them if I reduce it. I feel like I don’t really know how much food is appropriate at all, even though I’ve been doing this for a while.
 
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Wrench

No airstones.
I only have sponge filters.
Not all my tanks have wood, but my biggest pieces are max two feet long with a two or three inch diameter. The largest pieces are in my 29 gallon.
I set up a bucket of tap water yesterday and will test it again tonight to see if it has changed.
I don’t have much plastic decor - just a few plastic plants. I have two ceramic pieces of decor in two separate tanks. I’ve always had these plants and decor in the tanks and some have been in other tanks in the past.

One thing I’ve thought of: is it possible overfeeding has caused this? I am certain I feed too much - I have a problem with it and feel like I’m starving them if I reduce it. I feel like I don’t really know how much food is appropriate at all, even though I’ve been doing this for a while.
hilarious! Do not know if overfeeding will lower ph maybe BluMan1914 would be a better person to advise you on this...
 
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Wrench

Maybe try an airstone in one tank and not the other and see if it makes a difference between them?????
 
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BluMan1914

hilarious! Do not know if overfeeding will lower ph maybe BluMan1914 would be a better person to advise you on this...
I have no idea what could be wrong, or what could cause the problems.
All questions I would have were asked, and answered.
There has to be something in the tank that is causing this..but of course that is obvious.
 
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Wrench

I have no idea what could be wrong, or what could cause the problems.
All questions I would have were asked, and answered.
There has to be something in the tank that is causing this..but of course that is obvious.
Never hurts to ask around and you have been a good guide for me and my tanks from you helping me personally or reading what you have told others.
 
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trinity28

I just tested the tap water I had in a bucket for almost 24 hours. The pH has gone up a bit from 7.8 to 8, and GH and KH have remained at 10 and 6 respectively. It must be something in my tanks, not my tap water. My two newest setups are approximately 3 weeks old and their pH’s have already gone down to 6.0 and 5.8. I can’t think of anything I do that isn’t common in the hobby. Sigh...
 
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Wrench

I just tested the tap water I had in a bucket for almost 24 hours. The pH has gone up a bit from 7.8 to 8, and GH and KH have remained at 10 and 6 respectively. It must be something in my tanks, not my tap water. My two newest setups are approximately 3 weeks old and their pH’s have already gone down to 6.0 and 5.8. I can’t think of anything I do that isn’t common in the hobby. Sigh...
Wow........well, start taking things out I guess
 
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Chanyi

Go through each tank:
Measure pH and measure again (wait 24 hours after a water change to allow things to settle before testing)
Mark down your baseline pH for each tank.
Start writing down every thing that's in the tank, and note where you bought it and if it was aquarium specific or not. Everything in or added to the tank:
Substrate
Filter media
Water treatments
Decor
Food / supplements

Consider grabbing a new test kit just to be safe?


Are there any major issues with the tanks / livestock? or are we chasing a problem watching pH values??
 
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BluMan1914

Never hurts to ask around and you have been a good guide for me and my tanks from you helping me personally or reading what you have told others.
Glad I was able to help you.

Wow........well, start taking things out I guess
Yup...take out all decorations, and put everything back one piece at a time, test water after each piece is returned.
I would wait at least 2 days in between each time I put a piece of decoration back into the tank.
 
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trinity28

Go through each tank:
Measure pH and measure again (wait 24 hours after a water change to allow things to settle before testing)
Mark down your baseline pH for each tank.
Start writing down every thing that's in the tank, and note where you bought it and if it was aquarium specific or not. Everything in or added to the tank:
Substrate
Filter media
Water treatments
Decor
Food / supplements

Consider grabbing a new test kit just to be safe?


Are there any major issues with the tanks / livestock? or are we chasing a problem watching pH values??
No issues with livestock at all. I have quite a few different species throughout my tanks, even some considered sensitive, and they’re all completely fine.

What do you mean by “baseline pH”? The average or so?

Everything I have is aquarium specific and was either bought from other hobbyists, Petco/PetSmart, or my LFS. So at least I know that already.

I put an air stone in one tank to see if that does anything.

I will try taking things out one at a time. I’m thinking with only one tank? I don’t really want to disrupt all of them. Is it alright to leave the fish in there as I slowly remove things or should I temporarily move them to another tank? I guess I’m just worried they will lose their hiding spots and the snails will lose their eating spots.
 
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trinity28

I think I may also try to build a new setup from scratch and add only one thing over the course of one or two days at a time. Sort of an “engineer” instead of a “reverse engineer”, if you will. I just filled up a spare sterlite storage bin I have and added just a sponge filter. Every couple days I can try adding something new, like a water treatment or decoration, and see if I can get anything from that.
 
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trinity28

No issues with livestock at all. I have quite a few different species throughout my tanks, even some considered sensitive, and they’re all completely fine.

What do you mean by “baseline pH”? The average or so?

Everything I have in aquarium specific and was either bought from other hobbyists, Petco/PetSmart, or my LFS. So at least I know that already.

I put an air stone in one tank to see if that does anything.

I will try taking things out one at a time. I’m thinking with only one tank? I don’t really want to disrupt all of them. Is it alright to leave the fish in there as I slowly remove things or should I temporarily move them to another tank? I guess I’m just worried they will lose their hiding spots and the snails will lose their eating spots.
I forgot to mention in my first reply that I’m only having a problem with the pH and KH, but that my nitrogen cycles have all stalled due to the low pH too. I said that in my original post but just wanted to bring it up again. My fish are all fine, I’m guessing because the ammonia readings I’m getting are actually ammonium.
 
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Treestone

I forgot to mention in my first reply that I’m only having a problem with the pH and KH, but that my nitrogen cycles have all stalled due to the low pH too. I said that in my original post but just wanted to bring it up again. My fish are all fine, I’m guessing because the ammonia readings I’m getting are actually ammonium.

Has very similar outcomes like OTS (usually involving carbonic acid production) might be worth reading up on it yet I don't think that's the problem. Definitely something affecting the KH which affects all the other factors so you only need to test for that atm. No decorations such as rocks, wood, decor items can have that much of an effect on KH especially if they are different in each tank. Look at what is in all the tanks, especially if it directly relates to water chemistry.
 
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