Multiple Problems, One Tank (pH and tannin)

TeachersPet

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I have a 20 gallon fresh water tank that has a hob and a sponge filter. I also have an airstone and a heater. My decorations include a house/castle, four fake plants, a shell, a crocodile "skull" (fake), a log, and 3 cholla wood. Not sure what the substrate is; another teacher gave it to me. My tank occupants include 30-50 rcs and 2 bristlenose pleco.

Problem One - high pH. My tank used to have a pH between 7.2 and 7.6, however it has gradually increased to 8.4! I did a 10% water change, vacuumed, and changed the carbon filter. HELP!! (side note: it doesn't seem to be bothering the fish)

Problem Two - tannin. My cholla wood has turned the water a nice yellow/brown (sarcasm, it looks gross, clear but gross). I presoaked the logs for days and added one at a time to the tank. The first two didn't change the water, however after I added the third, I started to notice a color change. (again side note: it doesn't seem to be bothering the fish)

Any help would be greatly appreciated!

Aquarium Parameters
Temperature - ~80F Ammonia - 0
Nitrate - 0 Nitrite - 0
pH - 8.4 TDS - 350-420
 

PascalKrypt

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How often do you do water changes and how much do you change out? A 10% change likely won't make your PH budge a single decimal.

What kind of shell do you have in there?
Tannins are actually beneficial for most fish, so unless you hate the look, it's not something to worry about. It sounds like you do though, in which case remove the offending piece of wood and do a few large water changes. It can take weeks if not months for the wood to stop releasing tannins.
 

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Hi! Welcome to fishlore. I am assuming you are a teacher? It is wonderful you are giving your students the enjoyment of a classroom aquarium. To start off, it says you do not know about the nirtrogen cycle. This will be crucial to keep your tank healthy and the inhabitants alive. I suggest you read up on it, I can give you a brief summary if you would like. Not everything should be at 0 in a tank that has fish in it. Can you retest your water? A PH of 8.4 is kind of high for the pleco. However I have learned a stable PH is better than continuously messing with it. Your fish will likely adjust. Another thing is a pleco, even a bristle nose, should be in a larger tank. 20 gallon is on the small side for a bristle nose. The tannins will go away with frequent water changes. It is frustrating and can take many water changes, but it will fade over time. You can use the tannins leaching as a cool teaching/science experiment kind of thing for your students ;). Keep the carbon filter in and never change your filter media. It houses the beneficial bacteria and throwing it away will really mess up your tank. That will make more sense after you read up on the nitrogen cycle.
 

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1. The pH is weird- can you test the source water to see if that may have something to do with it? A 10% water change is pretty small and likely wouldn't change a whole lot. Most fish can and do adapt to higher pH so I wouldn't worry about it too much but finding out what is causing the change should be a goal. If it's not the water source it may be the shell. The calcium in it dissolving in the water raises pH and kH.

2. Tannins are actually beneficial to fish- especially shrimp- and are said to provide antibacterial and destressing qualities. All wood and botanical things added to a tank will release them over time. You can get rid of the tea-colouring by keeping up with waterchanges.
 
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I do weekly changes, however with just getting back from break, I missed some. On Friday I did 3. Yesterday I did one gallon. I am hesitant to do too much. I always notice a lot of molts after water changes and have even had some die with the "white ring of death". I can retest in the morning! I will also remove the shell (it is a beach shell). The color doesn't necessarily bug me too much, however other teachers mention it and that bugs me. I was using a starter and maintenance bacteria, should I still use it?
 

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TeachersPet said:
I do weekly changes, however with just getting back from break, I missed some. On Friday I did 3. Yesterday I did one gallon. I am hesitant to do too much. I always notice a lot of molts after water changes and have even had some die with the "white ring of death". I can retest in the morning! I will also remove the shell (it is a beach shell). The color doesn't necessarily bug me too much, however other teachers mention it and that bugs me. I was using a starter and maintenance bacteria, should I still use it?
That's a very small water change. Which conditioner are you using?
 

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TeachersPet said:
I do weekly changes, however with just getting back from break, I missed some. On Friday I did 3. Yesterday I did one gallon. I am hesitant to do too much. I always notice a lot of molts after water changes and have even had some die with the "white ring of death". I can retest in the morning! I will also remove the shell (it is a beach shell). The color doesn't necessarily bug me too much, however other teachers mention it and that bugs me. I was using a starter and maintenance bacteria, should I still use it?
The white ring may be caused by pH and alkalinity swings during water changes; I had a similar issue years ago with cherries because of some crushed coral I kept in the filter. I would remove the shell, as it is constantly leeching calcium carbonate which is raising your pH and KH, while the water you are replacing it with has different parameters. Although with only a 10% change, this is just me taking a wild guess as a 10% would barely affect your parameters.

I like tannins but if they bother you, you could always add Purigen to your filter. They will naturally dissipate with water changes over time. Plecos and shrimp both come from tannin-rich water.
 

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Removing the shell is a good choice. It would be really interesting what your substrate is. This can very well also be a reason.

I also like tannins, if you want to get rid of them quickly you could use activated carbon in the filter, but be aware that it messes with the nitrogen compunds.
I do a 20-50% change each week to keep nitrates low, I have to re-add tannins afterwards.

My suspiscion is, that after you removed the shell and did some bigger water changes, the ph should be back at around 7 soon. Provided it's not also the substrate.
 
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Addictedtobettas said:
That's a very small water change. Which conditioner are you using?
I use aqua safe

MacZ said:
Removing the shell is a good choice. It would be really interesting what your substrate is. This can very well also be a reason.

I also like tannins, if you want to get rid of them quickly you could use activated carbon in the filter, but be aware that it messes with the nitrogen compunds.
I do a 20-50% change each week to keep nitrates low, I have to re-add tannins afterwards.

My suspiscion is, that after you removed the shell and did some bigger water changes, the ph should be back at around 7 soon. Provided it's not also the substrate.
I will keep everyone posted! Maybe this summer I can temporarily relocate the fish and change out the substrate.
 

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I remove the shell. I would also caution you on doing too large of a water change. A big ph change can and will kill fish and shrimp pretty quickly. A ph change of one is a large change IMO. Multiple small water changes over the course of a day or two is much advised.
the calcium from the shell and no water changes could be the cause.
As others have stated the tannins are of no consequence and are actually keeping your ph from rising. Over time with water changes that will go away.
 
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Sien said:
Hi! Welcome to fishlore. I am assuming you are a teacher? It is wonderful you are giving your students the enjoyment of a classroom aquarium. To start off, it says you do not know about the nirtrogen cycle. This will be crucial to keep your tank healthy and the inhabitants alive. I suggest you read up on it, I can give you a brief summary if you would like. Not everything should be at 0 in a tank that has fish in it. Can you retest your water? A PH of 8.4 is kind of high for the pleco. However I have learned a stable PH is better than continuously messing with it. Your fish will likely adjust. Another thing is a pleco, even a bristle nose, should be in a larger tank. 20 gallon is on the small side for a bristle nose. The tannins will go away with frequent water changes. It is frustrating and can take many water changes, but it will fade over time. You can use the tannins leaching as a cool teaching/science experiment kind of thing for your students ;). Keep the carbon filter in and never change your filter media. It houses the beneficial bacteria and throwing it away will really mess up your tank. That will make more sense after you read up on the nitrogen cycle.
Should I use maintenance bacteria?

MacZ said:
Removing the shell is a good choice. It would be really interesting what your substrate is. This can very well also be a reason.

I also like tannins, if you want to get rid of them quickly you could use activated carbon in the filter, but be aware that it messes with the nitrogen compunds.
I do a 20-50% change each week to keep nitrates low, I have to re-add tannins afterwards.

My suspiscion is, that after you removed the shell and did some bigger water changes, the ph should be back at around 7 soon. Provided it's not also the substrate.
Is there any way to decide the type of substrate that is in the tank?
 

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TeachersPet said:
Is there any way to decide the type of substrate that is in the tank?
Check the bag that it came in...? You can also take a picture and show us. Where did you get it?
 

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Shells break down and add calcium To the water increasing hardness and ph. If you bought saltwater substrate this could be doing the same thing as well.

TeachersPet said:
Should I use maintenance bacteria?
No. It’s like flushing money down the toilet. Get the tank cycled and you’ll be fine.
 
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Salem said:
1. The pH is weird- can you test the source water to see if that may have something to do with it? A 10% water change is pretty small and likely wouldn't change a whole lot. Most fish can and do adapt to higher pH so I wouldn't worry about it too much but finding out what is causing the change should be a goal. If it's not the water source it may be the shell. The calcium in it dissolving in the water raises pH and kH.

2. Tannins are actually beneficial to fish- especially shrimp- and are said to provide antibacterial and destressing qualities. All wood and botanical things added to a tank will release them over time. You can get rid of the tea-colouring by keeping up with waterchanges.
I tested the tap water before conditioning and after. (Hopefully I read them correctly, I posted pictures of the results.)
Before
pH- 8.2
After
pH- 7.4
(Had it backwards at first. Switched them!)
 

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TeachersPet said:
Should I use maintenance bacteria?


Is there any way to decide the type of substrate that is in the tank?
I am assuming this is something like API quickstart, bottled bacteria. You can. I have not heard any hard evidence it actually helps, but better to use it and be safe IMO.
 
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PascalKrypt said:
Check the bag that it came in...? You can also take a picture and show us. Where did you get it?
So I got the substrate from the head science teacher who has a 30 gallon. She had it in a bucket so not sure what type it is. Here is a picture of it.
 

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TeachersPet said:
So I got the substrate from the head science teacher who has a 30 gallon. She had it in a bucket so not sure what type it is. Here is a picture of it.
That is large gravel from the looks of it. Yes, depending on what type of rock that is, it could definitely be raising your PH. It looks kind of white and chalky...

Do you have a hardness (GH) test? You could get a handful out, put in a glass, put in fresh water, check the hardness. Come back 24 hours later, stir the water and check again. If it has gone up, that is your culprit.
You can try it with PH but not sure if it would rise as fast as the GH.
 
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PascalKrypt said:
That is large gravel from the looks of it. Yes, depending on what type of rock that is, it could definitely be raising your PH. It looks kind of white and chalky...

Do you have a hardness (GH) test? You could get a handful out, put in a glass, put in fresh water, check the hardness. Come back 24 hours later, stir the water and check again. If it has gone up, that is your culprit.
You can try it with PH but not sure if it would rise as fast as the GH.
I don’t have a GH test. I thought the master kit I bought would have one but it doesn’t. I can go pick up some strips to test it though. Thank you!
 
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The pH ended up getting up to a 8.8! I have been doing small water changes twice a week to get it down. The last two weeks it had been staying at an 8.2. This morning I checked the parameters that way I know what they are before I do a water change this afternoon. My pH is climbing back up! It is an 8.4. Everything else was a 0. Why does it keep going up?
 

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