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beanbag

minimum safe kH value? Or a slightly acidic buffer?

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beanbag

Hello folks,

I currently have a tank that is gH7 kH5 that has Amanos and neos.  I was at the aquarium the other day and saw a Crystal red, and thought maybe I wanted to add one.  However, they like low pH, kH etc.  My pH is currently 7.4 according to my pH meter.

The plan is to first gently lower the kH of my tank.    From the reading I did, shrimp don't care about the actual kH value, but rather the pH stability.  So what is the minimum kH value that can still be "stable"?  Also, I had read a comment elsewhere that plants sometimes like carbonates, so maybe I still have to keep some kH?  (not injecting CO2 for now)

The second part is that I would prefer to have an inert substrate that won't break down over time, which means I don't want to run the typical buffering substrates like ADA, Fluval Stratum, etc.  Is there some object, like a rock or mineral, etc that can buffer the water just below pH 7?

I use RO water + Salty Shrimp GH/KH + potassium bicarb, so I can adjust the water however I want from the alkaline side.  But I don't know of an equivalent acidic buffering thing.

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sky99

Hello!

I used ada amazonia, and it was much too strong to my liking, i end up with 5-5.5 ph from 0KH water. However, with Akadama double hard line, i get 6.5 pH.

This is suitable for Neocaridina Davidi (i have multiple colonies with those settings), tigers (multiple colonies as well), and it is in the high range for crystal reds, taiwan bees, etc (from what i read, it should be in 5.5-6.5 pH).

As for the minimal kH possible, it depends on what is in your tank. If you don't have many things that can swing the pH, it should not move much once it's settled at the value the soil will set...

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beanbag

So I noticed with my pH meter that when the lights are on, it goes to 7.4, and when the lights are off, it goes to 7.2.  I guess this must be due to the CO2 levels in the water, even though I don't inject CO2.

I read a little about akadama, and it seems that different brands result in different pH.  But what is the chemical that does the actual buffering?  I wouldn't want to put it in my tank if it is something that runs out, but maybe put it in one of my filters as a form of media that is easy to replace.

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sky99

Hello,

Indeed, there shall be a pH variation depending on the plants that use/release CO2. However, 0.2 is comparable to the measurement error of a pH pen (i bought 2 and average the measures, and generally repeat the measuring 2-3 times if i need something more accurate).

Concerning the akadama, the one i bough is Akadama Ibaki, and i think that it is the brand of it, the model is "double hard line".

All technical soils will be "used up" at some point, and have to be replaced to get the buffering effect. However, the largest the effect on the water, the faster it will use the chemicals... For the same soil, if you're starting from 8.5 pH water to go to 6, it will probably use faster.

In my case, my tap water is pH 7, KH 0 and GH 0, and i get to 6.5 pH, so i expect it to last a long time.

If you want to do smaller doses of technical soil to lower "just a little" , i wonder if akadama will be strong enough for that?

Or maybe it would simply take a long time to buffer the water to the final value...

Anyway, in my case, the main goal is to keep shrimps. Some tanks are scaped, but if the soil "runs out", i'll probably either keep the scape with a population that likes the default water parameters, or redo the tank. But i have 11 tanks so i can move populations around i guess;

if you only have this tank i don't know how to proceed...

One thing i have noted though : Seyru stone increases the PH to aproximately 8 (again from near RO water parameters : GH/KH at 0, pH 7, TDS at 40), and the effect lasts extremely long (i have tanks with seyru stone that are years old, still the same parameters), so perhaps if we could find a rock that produces acidic water, it would create a long lasting buffer... With the large rock it takes more time than with technical soil to reach the final value, but basically lasts forever...

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beanbag
On 10/18/2018 at 3:49 AM, sky99 said:

so perhaps if we could find a rock that produces acidic water, it would create a long lasting buffer...

Yes, that would be nice.  Or even an acid buffer equivalent to baking soda.

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jayc
8 hours ago, beanbag said:

Or even an acid buffer equivalent to baking soda.

Baking soda does the complete opposite - it raises alkalinity. Don't use baking soda.

Baking powder can include an acidifying agent (cream of tartar) used for baking cakes, but that's not enough to raise acidity in your tank. Besides, you don't want to add baking powder in any tank, hence the name, it's for baking. Bicarbonate Soda or Baking soda, is the proper thing to use to raise alkalinity, since it lacks the agent for raising cakes. Side note: the acidifying agent (cream of tartar, lemon juice, buttermilk,etc) causes the baking soda to produce bubbles of CO2 which creates air pockets in the baked goods to rise and expand.  

You will also not find any rocks that reduce pH levels. In fact, most rocks do the opposite and raise alkalinity/pH. Rocks are either neutral (eg lava rock, shale) or they will raise pH (sandstones, limestones).

So if you want to reduce pH,

  • remove any rocks you might have.
  • Look at the source of your water. Tap water is high in carbonates and pH usually. So you need to cut that way down or use RO or rain water.
  • Substrate is the other option. Plant soils or technical soils as we are referring to it in this post can help and as mentioned here will run out eventually. But it helps maintain pH and avoids wide swings in pH. But if you don't want to use it we need to look elsewhere. Oh, that chemical that reduces pH is called tannins - it's acidic and is what gives the water a brown rusted colour, like the waters of the Amazon river. Tannins have a side effect of being antibacterial and antifungal. 
  • Look at a river bed for clues in reducing pH. Drift wood, decaying leaves, soil.
  • Lots of driftwood and dried leaves like Cattapa leaves will help reduce pH eventually. It's natural and changes are slow and gradual unless you put too much in. Alder Cones are very, very effective at reducing pH. 5-6 cones in a 100L tank can reduce pH well below 5 if left in there long enough. So regular monitoring is required and remove when the target pH is reached. Did i say Alder cones are effective at reducing pH? These are the best. A few tucked away in an old stocking in an external filter will do wonders.

 

Combine plant soil substrate, RO/rain water, and alder cones together and you will reduce pH quite quickly. 

If you use one or two of these methods but keep using tap water that is high in KH / pH every water change and have limestone rocks, the effect cancels each other out and you will not move pH either direction in a very meaningful way. 

Whatever you do, do it gradually if you already have livestock in the tank.

Edited by jayc

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beanbag

Thanks for the useful info.  You may have already answered my question, but just to be clear, I mean if there is an acidic counterpart to baking soda., i.e. a chemical that makes the water slightly acidic while still providing buffering.

There must be some specific chemical / mineral in Akadama, Fluval Stratum, etc that does this, so I would like to isolate it.  Then I could add it to my remineralized RO water just like I do with potassium bicarbonate.  I guess it doesn't need to be a physical object that sits in the tank water.

From what you said about alder cones, it sounds like a weak acid, not a buffer.  That is, it won't stabilize at a certain pH, but will keep getting more acidic.  If I recall from chemistry, a buffer consists of a weak acid + weak base and either part takes turns kicking in to keep the pH near a fixed level.

As I mentioned earlier, maybe I can take objects and put them inside my filter, such as these alder cones, peat, akadama, etc?

My other question would be if I am aiming for a slightly acidic pH in order to host crystal red shrimp, should I get the Salty Shrimp GH if I already have the GH/KH version?  The thing I am not sure about is how the small amount of KH in the GH/KH version will react with the weak acids.  Will it also form a buffer on the acidic side, with both compounds in equilibrium, or will the carbonate part simply precipitate out, leading to still a weak acid with little buffering?

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Zoidburg

There are products out there that are meant to lower the pH.... however, these are temporary and can cause fluctuations in pH and raise the TDS through the roof.... not recommended.

 

This is why many people who keep Caridina that seem to thrive in low pH conditions use a buffering substrate (Fluval is not recommended by a vast majority), RO water and GH minerals.

 

If you want to use things like alder cones, peat moss, indian almond leaves, etc, to lower the pH, then you'll need to use a lot, pre-treat all incoming water and expect for your water to be tea colored... possibly even a dark color to be able to achieve a lower pH.

 

If you are not using a buffering substrate in the tank, then you want KH to help keep the pH stable.

If you are using a buffering substrate to lower the pH, you do not want KH. This would cause a swing in parameters.

 

 

Not recommended to skimp out on caring for Caridina that are kept in low pH parameters. That said, there is a breeder in Oregon who's raising CRS in tap water with a GH remineralizer. He said he struggled to get his colony to that point and had many losses but the colony is stable now. Probably the main reason he's able to make this work is because he has *really* soft tap water....

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