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Discussion Starter #1
Hello,

Recently I started a planted tank complete with CO2 injection. In past tanks I have been a bit agnostic to some parameters such as KH and GH but they are important and I want this tank to be my most professional yet.

I am using test strips until I get a new testing kit and the values for my tap water and tank water:

San Diego Tap:

KH ~120ppm
GH >300ppm
pH ~7.0-7.2 pH

Tank Water with CO2 injection (parameters identical when CO2 is on and hours after it is off

KH ~30ppm
GH >300ppm
pH <6.2

The problem:

I would like to have softer water while at the same time retaining strong buffering ability as I fear that my pH is likely dropping lower than 6 with the CO2 on ... especially with such a low KH value.

Other externalities:

*24 gallon JBJ cube
*I have Fluval Stratum which apparently helps keep pH down as well
*Lots of driftwood, heavily planted
*Dose flourish 2x a week
*No fish currently but hoping to stock with 12 rasbora hengeli (or ember tetras... still haven't decided), 5 otocinclus, 3-4 peacock gobies and 1 pair of apistogramma (cacatuoides or mcmasteri)
*Change 10% water twice a week

Things I could do:

1) cut my tap water with RO water. This would help with the hardness; however, it would also affect the amount of natural carbonate buffering would be present in the water. Ultimately this would help on one front but cause greater volatility with the pH because of the carbonic acid being generated by the additon of C02.

2) pre-treat my tap water with aeration with peat. This should cause the uptake of Ca+ and Mg+ ions, some acid would be released affecting the alkalinity but hypothetically not as much as I have with C02 injection. That is an assumption though and I have no idea how much alkalinity would be preserved which would leave me with the same issue as before.

3) Either option 1 or 2 but then add sodium bicarbonate or some commercial buffer to help buffer but the overall hardness of the water would still be felt by the fish the same way.

Are my assumptions correct? Any other ideas around my dilemma? If there is an article or sticky thread that would answer feel free to comment with the link as well.

Thanks!
 

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I would like to have softer water
Any particular reason why? Is there a specific species you were unable to keep in the past due to your water parameters? Have you seen a problem that you think can be attributed to not having softer water?

Altering your water parameters to reach a specific goal can be troublesome in the long run; especially if you have no real reason for doing so. I'm a fan of the KISS method so I'd say its best to avoid having to do that if at all possible. You can still have a "professional" tank without having to be a mad scientist!
 

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Discussion Starter #4
Any particular reason why? Is there a specific species you were unable to keep in the past due to your water parameters? Have you seen a problem that you think can be attributed to not having softer water?

Altering your water parameters to reach a specific goal can be troublesome in the long run; especially if you have no real reason for doing so. I'm a fan of the KISS method so I'd say its best to avoid having to do that if at all possible. You can still have a "professional" tank without having to be a mad scientist!
It is my understanding that the apistogramma species prefer softer water. In the past I have kept amazonian fish in what was effectively liquid rock and while they lived I don't know if I would say they thrived... they lacked the kind of vibrant coloration that is indicative of a healthy fish... though that could be because I haven't consistently fed live foods.

Overall I want to provide stable parameters that are best suited to the fish I am keeping... if there is a simple way of doing so I'm interested in trying. If it is a futile endeavor I'd rather find out before I do too much experimenting once there are fish in the tank.

Bump:
Also, I think your readings may be off for the San Diego tap water. See the last several pages here - https://www.sandiego.gov/sites/default/files/2015_adwqr_final_w_revisions.pdf
In the attachment I have included the section with the water parameters discussed. It matches pretty closely to what I posted as coming from the tap.

Bump: while I have some concern about the hardness being high my greatest concern is about the volatility with the pH... because the test strips I am using don't go below pH of 6.2, it is very possible that my intraday pH readings could be going between 6.2-5... which is a big range especially since pH is measured logarithmicaly.

Should I be worried about such volatility? I have read in some places you don't want more than a .2 swing within a day. My alkalinity is greatly affected by the C02 injections so each day the buffering capacity is being eaten into.

Someone with any of the species I mentioned feel free to let me know if I am overthinking the pH/GH/KH.

Thanks!
 

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In the attachment I have included the section with the water parameters discussed. It matches pretty closely to what I posted as coming from the tap.


Thanks!
I'm getting pH of >8.0 out of the tap at my place in South Park (San Diego), which is in line with that chart. I'm using Fluval Stratum and am getting the same results you are, more like 6.4 pH but similar, but I'm using Excel for CO2. With the Fluval Stratum, its buffering capacity will really affect your ability to raise pH, and not sure what adding enough alkaline to overcome the buffer will do to the substrate. The advice I got from people was not to try to change the pH. The CO2 folks will undoubtedly weigh in as I am sure many of them get low pH, but wanted to add the note about not trying to overcvome the substrate buffer.
 

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That substrate will buffer him back down right away.
I'm downtown so I should have the same water as you I would assume, when I'm home again I will check the tap water.

I agree that the substrate buffering is likely pointless to battle.

Today I saw a dead pond snail... it was an old large one that I got from a friends tank... it had a weak portion of its shell when I got it but this morning it was dead and the weak portion was dissolved... could the acidity of the water been able to do that in just a week?!

Maybe I should turn down the C02? It was at about 3-4 bubbles per second, in a 24 gallon that probably goes a long way?

I'm getting pH of >8.0 out of the tap at my place in South Park (San Diego), which is in line with that chart. I'm using Fluval Stratum and am getting the same results you are, more like 6.4 pH but similar, but I'm using Excel for CO2. With the Fluval Stratum, its buffering capacity will really affect your ability to raise pH, and not sure what adding enough alkaline to overcome the buffer will do to the substrate. The advice I got from people was not to try to change the pH. The CO2 folks will undoubtedly weigh in as I am sure many of them get low pH, but wanted to add the note about not trying to overcvome the substrate buffer.
pH out of tap for me was 7.2-7.8
 

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Discussion Starter #10
I think my next step will be to get a drop counter to make sure that I'm not inadvertently adding too much CO2. In the event that I am adding to much, I will lower my C02 and do more regular water changes to make sure I am introducing enough alkalinity to help mitigate the buffering from the substrate and the carbonic acid.

In terms of the water hardness, not much I can do... the San Diego report on the water quality seems to show that the hardness is just over 300 ppm which is not horrible. Since my test strips only went to readings of 300 I was fearing it could be much higher. I could add a peat bag to my filter and call it a day.
 
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