blackwater tank cycling?

[anewbie]

I would. It would either make your peat last longer or make it not necessary at all. It will make the pH a lot more predictable. Any strong acid will do. Cobra venom sounds great. I use phosphoric acid, but if you can't find that, "API PH Down" is 9.6% sulfuric acid and pretty easy to buy in small volumes. Test it outside the aquarium to understand how many drops you need to add per gallon to your incoming water to get the pH to where you want it.

The tank pH will want to rise, so I would:

• Assuming there are no animals in the tank, first get the tank to a desirable pH, maybe just 10 drops or so at a time.
• Water change with water at the correct pH.
• Measure your tank pH for the next few days. It will rise for a few days. You'll likely need to add more acid to your incoming water until you reach a point where the pH is stable in between water changes. It will always want to rise if you go longer than that.

It took me a few weeks maybe to get it to where I know exactly how much acid to add to my incoming water. Once your pH is stable, then look at new plant growth starting on that date and decide when you're comfortable adding your canary animals.

Good luck!

I have a few inexpensive hatchet fishes in the tank - if i add the acid to the sump a few drops at a time will that harm them? I just want to slowly lower the ph.

 

[anewbie]

I would. It would either make your peat last longer or make it not necessary at all. It will make the pH a lot more predictable. Any strong acid will do. Cobra venom sounds great. I use phosphoric acid, but if you can't find that, "API PH Down" is 9.6% sulfuric acid and pretty easy to buy in small volumes. Test it outside the aquarium to understand how many drops you need to add per gallon to your incoming water to get the pH to where you want it.

The tank pH will want to rise, so I would:

• Assuming there are no animals in the tank, first get the tank to a desirable pH, maybe just 10 drops or so at a time.
• Water change with water at the correct pH.
• Measure your tank pH for the next few days. It will rise for a few days. You'll likely need to add more acid to your incoming water until you reach a point where the pH is stable in between water changes. It will always want to rise if you go longer than that.

It took me a few weeks maybe to get it to where I know exactly how much acid to add to my incoming water. Once your pH is stable, then look at new plant growth starting on that date and decide when you're comfortable adding your canary animals.

Good luck!

Does this look good - food grade @ 75%:

Amazon.com

or better 85% :

Amazon.com

 

[Ben Rhau]

Does this look good - food grade @ 75%:

Amazon.com

or better 85% :

Amazon.com

I wouldn't use those, they're too strong. I think it's not very safe. I found one online that was 10% (which is about 1M) and came in a small volume. There's not a huge advantage to phosphoric acid over sulfuric (pH Down) given that phosphate and sulfate are both macronutrients for plants.

 

[Ben Rhau]

I have a few inexpensive hatchet fishes in the tank - if i add the acid to the sump a few drops at a time will that harm them? I just want to slowly lower the ph.

I would take the fish out first. You have so much water, 2 or 3 drops won't do anything. But if you add more, I can't predict how quickly your pH will move.

 

[anewbie]

I wouldn't use those, they're too strong. I think it's not very safe. I found one online that was 10% (which is about 1M) and came in a small volume. There's not a huge advantage to phosphoric acid over sulfuric (pH Down) given that phosphate and sulfate are both macronutrients for plants.

How about this:

amazon.com/Phosphoric-Acid-Food-Grade-Testing/dp/B009G9D0IA/

It is 25% - i'm worried that if i go lower it won't do much given the size of the aquarium (100 gallons);
also i can't remove the fishes - there is zero chance i could catch them - i can barely see them - but i can put the acid in the sump so it will dillute before it reaches the fish.

 

[Ben Rhau]

Yeah, that product would definitely work. I still don't recommend adding directly, but I understand where you're coming from. If I HAD to do it that way, I would go way slower and more conservative than is necessary. Adding amounts that don't move the pH at all at first, just to see how much I need to add to lower it by less than 0.5 units at a time.

 

[anewbie]

Yeah, that product would definitely work. I still don't recommend adding directly, but I understand where you're coming from. If I HAD to do it that way, I would go way slower and more conservative than is necessary. Adding amounts that don't move the pH at all at first, just to see how much I need to add to lower it by less than 0.5 units at a time.

At that concentration do i need to worry about it splashing or what have you when it hits the water - or if i just poor in small amount it should be just like pouring water. I'll put in a small amount - maybe a 1/2 lid amount - wait 48 hours and retest ph ?

 

[Ben Rhau]

I would personally count drops using a transfer pipette. It might be a lot of drops, but it's easier to reproduce and safer than pouring. If you pour, some might drip down the side of the bottle and touch something you don't want it to. Wear nitrile gloves and keep your bottle in a secondary container. Having worked in labs, I think it's better to be safer than necessary.

The pH change will occur quickly. Maybe test 10 minutes after adding to see what happened immediately. With fish in there, I might shoot for 0.5 units at a time, wait an hour before adding more, and not reducing too much in a day. You'll need to test again the next day to see how much it went up.

 

[anewbie]

I would personally count drops using a transfer pipette. It might be a lot of drops, but it's easier to reproduce and safer than pouring. If you pour, some might drip down the side of the bottle and touch something you don't want it to. Wear nitrile gloves and keep your bottle in a secondary container. Having worked in labs, I think it's better to be safer than necessary.

The pH change will occur quickly. Maybe test 10 minutes after adding to see what happened immediately. With fish in there, I might shoot for 0.5 units at a time, wait an hour before adding more, and not reducing too much in a day. You'll need to test again the next day to see how much it went up.

Instead of drops how many ml would you suggest - ordering a measuring pipette and i can just add a certain amount of ml. I was thinking either 5ml or 10ml a shot.

 

[Ben Rhau]

I ml is 20 drops. How much you add will need to be determined empirically. I wouldn’t add more than 1 to start, perhaps less.

 

[anewbie]

I ml is 20 drops. How much you add will need to be determined empirically. I wouldn’t add more than 1 to start, perhaps less.

Ok. 1ml it is ; thank you for your assistance.

 

[MacZ]

Erm... when using only botanicals and leaves and their extracts it takes months of constant addition to get pH below 6 but then it stays down quite dependably. In case of my tank (recently TDS at 30) it took 5 months. The method using these materials is only for the patient with time on their hands.

• Leaves won't affect the pH much.
• Peat will lower the pH, but it's hard to predict by how much because peat isn't uniform, and it can be exhausted. My guess is that there isn't enough relative to your volume of water.

I agree to both.

 

[anewbie]

Erm... when using only botanicals and leaves and their extracts it takes months of constant addition to get pH below 6 but then it stays down quite dependably. In case of my tank (recently TDS at 30) it took 5 months. The method using these materials is only for the patient with time on their hands.


I agree to both.

Well my hope is using acid will accelerate the process and then it will stabalize - i won't be doing a water change for at least a month as the fish density is very low. I think if i can lower it 0.8 (6.7 to 5.9) it will be 'good enough' for the stocking. When i do a water change i will set the water in a 40 gallon pail over night - i guess with a little acid to get it close to whatever tank value i have.

 

[MacZ]

What I'm always a bit critical of: I don't think pH is the decicive factor but conductivity. A low conductivity tank with a relatively high pH (around 6) is often better than a low pH tank with a high conductivity due to added strong acids.

But that's me, I guess.

 

[anewbie]

What I'm always a bit critical of: I don't think pH is the decicive factor but conductivity. A low conductivity tank with a relatively high pH (around 6) is often better than a low pH tank with a high conductivity due to added strong acids.

But that's me, I guess.

So the acid will raise tds ? Will it take water changes to remove the tds increase by acid ? My ec pen has a 500 and 700 choice but i think ec was around 8 (tds 26).

 

[dw1305]

Hi all,

I'm having a bit of problem; if the ph probe i am using is accurate the ph is staying around 6.6; the tds has remained around 25

The problem is with the pH meter and the <"low conductivity (TDS meters measure electrical conductivity) of the water">, rather than the water itself.

As the others have said I wouldn't worry too much, just try and keep the conductivity low, probably below 50 ppm TDS (64 or 100 microS dependent on which conversion factor your meter uses).

You can raise the conductivity of your sample water with a <"neutral salt">, NaCl will do, but it needs to be pure NaCl.

I'm always dumbfounded when I hear people warn that low TDS tanks are subject to pH crash. I want the pH to stay low, and it takes work to figure out how.

I just think pH and buffering generally are much misunderstood, partially because you can't <"extrapolate from hard to soft water"> and, unfortunately, there is a lot of misinformation from the <"sellers of pH buffers"> etc.

The problem with "strong acids" is that they don't add any buffering, they disassociate fully, whereas "weak acids" don't and they have two disassociation constants. Personally I'd keep well away from both concentrated (conc.) acids and strong acids. Have a look at <"citric acid"> and <"All the leaves are brown">

If you look at the figures that @Tom C etc recorded from black water rivers they have low pH and absolutely tiny conductivity values and <"that is the problem for us">. You can reduce the pH with acids, but then you've raised the conductivity.

From <"https://www.tomc.no/page.aspx?PageId=64">

The water: pH: 5,32
Conductivity: 21 µSiemens/cm
T: 24,0 °C
(after heavy rain,
at the end of the dry season)

As you approach pure H2O pH becomes fundamentally meaningless, mainly because it is both a log10 value and a ratio and this makes pH unstable. I try to encourage people to use a different approach now, where you look at changes in ionic composition, rather than pH. The simple version is that in hard water you need large changes in water chemistry to change pH and in soft water small changes in water chemistry cause large changes in pH.

All we need to do is avoid large changes in water chemistry.

cheers Darrel

 

[anewbie]

Hi all,

The problem is with the pH meter and the <"low conductivity (TDS meters measure electrical conductivity) of the water">, rather than the water itself.

As the others have said I wouldn't worry too much, just try and keep the conductivity low, probably below 50 ppm TDS (64 or 100 microS dependent on which conversion factor your meter uses).

You can raise the conductivity of your sample water with a <"neutral salt">, NaCl will do, but it needs to be pure NaCl.

I just think pH and buffering generally are much misunderstood, partially because you can't <"extrapolate from hard to soft water"> and, unfortunately, there is a lot of misinformation from the <"sellers of pH buffers"> etc.

The problem with "strong acids" is that they don't add any buffering, they disassociate fully, whereas "weak acids" don't and they have two disassociation constants. Personally I'd keep well away from both concentrated (conc.) acids and strong acids. Have a look at <"citric acid"> and <"All the leaves are brown">

If you look at the figures that @Tom C etc recorded from black water rivers they have low pH and absolutely tiny conductivity values and <"that is the problem for us">. You can reduce the pH with acids, but then you've raised the conductivity.

From <"https://www.tomc.no/page.aspx?PageId=64">


As you approach pure H2O pH becomes fundamentally meaningless, mainly because it is both a log10 value and a ratio and this makes pH unstable. I try to encourage people to use a different approach now, where you look at changes in ionic composition, rather than pH. The simple version is that in hard water you need large changes in water chemistry to change pH and in soft water small changes in water chemistry cause large changes in pH.

All we need to do is avoid large changes in water chemistry.

cheers Darrel

So you are saying (i think) ignore ph and just be happy tds is 25 ec is 8 and it will all work out ?

 

[Tom C]

... Personally I'd keep well away from both concentrated (conc.) acids and strong acids. Have a look at <"citric acid"> and <"All the leaves are brown">

Have you ever considered Fulvic Acid, Darrel?

After all, it is an important part of humic substances (in fresh water), is found naturally in the fish's habitat, and should therefore be good for fish from humic-rich waters?

 

[dw1305]

Hi all,

So you are saying (i think) ignore ph and just be happy tds is 25 ec is 8 and it will all work out ?

Yes, just add some "botanicals" and over time the pH should drop. The good thing with conductivity is that it is a linear scale and, even cheap, meters are robust and accurate. If you don't have many ions? You don't have much carbonate buffering, it is just easy and straightforward.

If there was a pH or nitrate etc. meter where you could just dip it on and get a reliable and accurate reading? I'd recommend them, but there isn't and I don't.

As an example our tap water is from a deep limestone aquifer and about 700 microS, and nearly all of that is Ca++ and 2HCO3- ions. Great to drink, but not very suitable for Apistogramma. Water straight out of the DI unit is ~0 microS, but it will rise to 4 - 5 microS purely as atmospheric CO2 dissolves into it. Water is a very efficient amphoteric solvent.

Have you ever considered Fulvic Acid, Darrel?

Not as a bottled additive, but I'm pretty sure there is nothing wrong with it. There are some references at the bottom of <"https://tanninaquatics.com/blogs/the-tint-1/humic-substances-in-freshwater-aquariums">. I'm guessing that using a wider range of "botanicals" would more closely replicate the mix of humic and fulvic acids found in the Rio Negro etc.

I'll link some scientific aquaculture references in a separate post.

The main reason for me would be I'm too "careful" with my money to buy anything that I can get for free. I tend to use a random mix of Alder cones (Alnus spp.) and Oak (Quercus spp.), Hornbeam (Carpinus betulus), Camellia (C. x williamsii) and / or evergreen Magnolia (M. grandiflora) leaves, purely because I can pick all of these up from adjacent to the tanks. If I wanted a "stronger" black water I'd go for Oak bark and acorn "cups".

I actually add some Alder cones and structural leaf litter to all the tanks and I would recommend it to everybody, even if they don't keep "black water" fish.

After all, it is an important part of humic substances (in fresh water), is found naturally in the fish's habitat, and should therefore be good for fish from humic-rich waters?

I think that is right, and it would also act as a chelator.

cheers Darrel

 

[dw1305]

Hi all,

I'll link some scientific aquaculture references in a separate post.

Here are a couple from the Steinberg lab. at Humboldt University in Berlin. <"https://www.apistogramma.com/forum/...lin-the-importance-of-humic-substances.20876/"><"https://scholar.google.com/citations?user=WHwbmFMAAAAJ&hl=en">

<"Lieke, T. Fulvic acid as water additive in aquaculture">. You can download the full text of her thesis (in pdf format) from the link.

<"Lieke, T., Steinberg, C.E.W., Pan, B. et al. Phenol-rich fulvic acid as a water additive enhances growth, reduces stress, and stimulates the immune system of fish in aquaculture. Sci Rep 11, 174 (2021). https://doi.org/10.1038/s41598-020-80449-0">

<"Thora Lieke, Christian E.W. Steinberg, Sandra Bittmann, Sascha Behrens, Seyed H. Hoseinifar, Thomas Meinelt, Klaus Knopf, Werner Kloas,
Fulvic acid accelerates hatching and stimulates antioxidative protection and the innate immune response in zebrafish larvae, Science of The Total Environment, 796, (2021), 148780">.

cheers Darrel