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Can I make blackwater using my tap water?

Ben Rhau

Apisto Club
Messages
633
Location
San Francisco
Hi all,

You've swapped a proton and I think that the proton (H+) would be a slightly less conductive than ions with a higher valency, like calcium (Ca++), and you swapped them 1 : 1.

I think size is also important (smaller = more conductivity), and you can't get any smaller than a H+ ion, so I'm guessing they balance out, but you need a <"real scientist at this point">.

The added protons would lower pH, because one definition of an acid is a <"proton donor">.

cheers Darrel
Haha, I can’t help you with the “real scientist” bit. :)

I understand this is happening on the molecular level, but in aggregate I don’t recall seeing a big conductivity change before and after. Possibly went down slightly, but the difference was not far from the margin of error. Perhaps enough to simulate rainfall?
 

dw1305

Well-Known Member
5 Year Member
Messages
2,840
Location
Wiltshire UK
Hi all,
I can’t help you with the “real scientist” bit.
That is where I struggle, I'm not a chemist.
Possibly went down slightly, but the difference was not far from the margin of error.
I think it should go down, but pretty minimally.
Perhaps enough to simulate rainfall?
I might try lowering the temperature and / or waiting for low barometric pressure?

cheers Darrel
 

Mazan

Well-Known Member
Messages
369
Just rereading this and linked threads as I am finally ready to start the project. It took a while as I first had to catch and sell the baby Guianacaras (relatively easy with bottle traps), but then catching the remaining small fishes was more problematic - I had to take all the wood and floating plants and virtually all of the water out to catch them and even then I left a couple of ruby tetras, a Copella and a rineloricaria (which must have buried itself in the sand). Then I had to catch the pike cichlids that were in a tank measuring 200 x 65 x 65 cm with a lot of roots and branches where the pike cichlids spend most of the time so nets were not really an option. . The female was easy, she went into a bottle trap baited with shrimp pieces immediately, but the male proved much more difficult, I finally managed to get him yesterday with a different trap design.

So now I am going to look for some peat without additives, but also revisiting the possibility of adding acids. We don't get many API products here and I haven't seen pH Down, but there is a Seachem pH acid regulator which uses phosphate buffers - is this the same? And might this increase phosphate levels in the tank potentially leading to more algae or even the dreaded Cyanobacteria? Or increasing TDS /consuctivity a lot?

Another question I have concerns water changes. In that tank I have been in the habit of changing 20-30% of the water weekly, but I notice @MacZ that in one of your posts you say you don't do water changes but just top off the tank with RO water. Could I do the same with tap water? Or distilled? As I think water changes prevented the pH from going down when I have previously used botanicals and peat.

A bit more info about the tank - it is 240L but the actual volume is less as I have some big pieces of wood and a fair amount of sand in there. The only fish are the two dwarf pikes, the catfish and the two ruby tetras are still there, don't know for how long...the tank has 3 large amazon swords that frequently produce offspring, a java fern, Vallisneria, java moss and is virtually covered with frogbit and water lettuce. At the moment the TDS in the tank is 27. I have already added a few leaves from here, but they don't produce any visible tannins. I am going to try to find almond leaves but is proving difficult lately.
 
Last edited:

Mike Wise

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Staff member
5 Year Member
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11,399
Location
Denver, Colorado, U.S.A.
IMHO water changes are necessary for a healthy aquatic environment. In nature water is continually being changed. There are exceptions of course, like residual pools but in most cases fish die. The amount of water chan depends on the bio-load. You are continually adding to it whenever you feed your fish. Topping off a tank with anything less than 0 TDS distilled water will slowly increase the hardness of the water. Water evaporates but DOCs (dissolved organic compounds) do not. As for pH regulators I feel it is best to use natural products and not play chemistry set with a tank of fish.
 

Ben Rhau

Apisto Club
Messages
633
Location
San Francisco
We don't get many API products here and I haven't seen pH Down, but there is a Seachem pH acid regulator which uses phosphate buffers - is this the same? And might this increase phosphate levels in the tank potentially leading to more algae or even the dreaded Cyanobacteria? Or increasing TDS /consuctivity a lot?
Phosphate buffers combine a weak base with its conjugate acid. They will definitely increase the conductivity of your water, and as such, have no practical purpose when reducing pH in aquariums.

You don't need to buy API products. Can you find something on Amazon or an online lab supply store? Dilute strong acids are also used for making wine and beer, so some vendors sell relatively small quantities (like 1L). You're looking for as DILUTE a solution of HCl, Sulfuric acid, or Phosphoric acid you can find. By dilute, I mean no higher than 1M or 1N. Sometimes it's expressed as %, so that would be 5% or below for HCl, or 10% or below of the other two.

Even those dilute solutions should be handled very carefully. I use gloves and a secondary container.


As I think water changes prevented the pH from going down when I have previously used botanicals and peat.
If you're doing a 20% water change, you need something to neutralize the carbonate buffering that's inherent in distilled water that's exposed to air. You could do this with organics, but those eventually deplete, as you've observed. What I've done is determine (through experience) how many drops of acid I need to add (before adding to the tank) in order to keep the tank below a certain pH between water changes. It will take some time and effort. Preferably worked out before you have animals in the tank.
 

dw1305

Well-Known Member
5 Year Member
Messages
2,840
Location
Wiltshire UK
Hi all,
but there is a Seachem pH acid regulator which uses phosphate buffers - is this the same?
No, and worse than useless <"https://apistogramma.com/forum/threads/seachem-acid-buffer.915/#post-5410">.
the tank has 3 large amazon swords that frequently produce offspring, a java fern, Vallisneria, java moss and is virtually covered with frogbit and water lettuce.
Perfect.
At the moment the TDS in the tank is 27.
Also perfect. I wouldn't change anything at that point.
I have already added a few leaves from here, but they don't produce any visible tannins.
Where are you located? Can you pick your own Oak (Quercus spp.) or Alder (Alnus) "cones"? There are other "leaf" possibilities <"https://apistogramma.com/forum/threads/apistogramma-sp-breitbinden.9042/#post-50647">
I am going to try to find almond leaves but is proving difficult lately.
Are there other types of trees you can access? I trained as a botanist so I may have some idea of what trees they are from a photo.

cheers Darrel
 

Mazan

Well-Known Member
Messages
369
Thanks for all the replies!

IMHO water changes are necessary for a healthy aquatic environment. In nature water is continually being changed. There are exceptions of course, like residual pools but in most cases fish die. The amount of water chan depends on the bio-load. You are continually adding to it whenever you feed your fish. Topping off a tank with anything less than 0 TDS distilled water will slowly increase the hardness of the water. Water evaporates but DOCs (dissolved organic compounds) do not. As for pH regulators I feel it is best to use natural products and not play chemistry set with a tank of fish.
To be honest these have always been my opinions too. I think leaving a long period between water changes then doing a large one can sometimes trigger spawning, but might be difficult in my case to have enough water at the correct pH to do this.
Phosphate buffers combine a weak base with its conjugate acid. They will definitely increase the conductivity of your water, and as such, have no practical purpose when reducing pH in aquariums.

You don't need to buy API products. Can you find something on Amazon or an online lab supply store? Dilute strong acids are also used for making wine and beer, so some vendors sell relatively small quantities (like 1L). You're looking for as DILUTE a solution of HCl, Sulfuric acid, or Phosphoric acid you can find. By dilute, I mean no higher than 1M or 1N. Sometimes it's expressed as %, so that would be 5% or below for HCl, or 10% or below of the other two.

Even those dilute solutions should be handled very carefully. I use gloves and a secondary container.



If you're doing a 20% water change, you need something to neutralize the carbonate buffering that's inherent in distilled water that's exposed to air. You could do this with organics, but those eventually deplete, as you've observed. What I've done is determine (through experience) how many drops of acid I need to add (before adding to the tank) in order to keep the tank below a certain pH between water changes. It will take some time and effort. Preferably worked out before you have animals in the tank.
Thank you, I think I could probably find pure acids her somewhere, but as I already have the fish in the tank it will be safer, though slower to stick with natural methods.
Where are you located? Can you pick your own Oak (Quercus spp.) or Alder (Alnus) "cones"?
I am in the Andes of Ecuador, no oak here but we do have alder (the Andean species) and I have some cones of this. Most leaves I have tried from immediately around here do not release tannins, but do last longer in the tanks than almond leaves. A common tree round here is "Nogal" , not sure of the scientific name but will find out, the fruit is virtually identical to walnuts. Of course the most common tree is Eucalyptus, which is introduced, but widespread, I can easily get leaves and seeds, but not sure if these would be good? Later I will find a more complete list of species found here.
 

Mazan

Well-Known Member
Messages
369
Where are you located? Can you pick your own Oak (Quercus spp.) or Alder (Alnus) "cones"? There are other "leaf" possibilities <"https://apistogramma.com/forum/threads/apistogramma-sp-breitbinden.9042/#post-50647">
So here are a few of the trees I can think of that we have close to the house:
Nogal - Juglans neotropica
Capulí - Prunus salicifolia
Cedro- Cedrela montana
Aliso - Alnus acuminata

There are a lot more, especially just a little higher up where there is more native vegetation, but I honestly don't know the names of most of them.
 

dw1305

Well-Known Member
5 Year Member
Messages
2,840
Location
Wiltshire UK
Hi all,
Eucalyptus leaf is no good, the seed pods might be though. I've got access to a fruiting Eucalyptus gunnii, so I'll try with that (but not in a tank with any fish). I'll heat the seed pod first to get it to release any seed. The advantage would be that the seed pods are persistent on the tree (over several years) so they would always be available.
Most leaves I have tried from immediately around here do not release tannins, but do last longer in the tanks than almond leaves. A common tree round here is "Nogal" , not sure of the scientific name but will find out, the fruit is virtually identical to walnuts.
Nogal - Juglans neotropica - That one might be alright, I'd probably try the shells, not the leaves?
Aliso - Alnus acuminata - The leaves won't add any tannins, but the bark should.
Capulí - Prunus salicifolia
Cedro- Cedrela montana
I'd guess they won't be suitable, but I don't actually know.

cheers Darrel
 

MacZ

Well-Known Member
Messages
3,442
Location
Germany
They will all release humic substances when decomposing. Just not much directly visible stuff.
 

Mazan

Well-Known Member
Messages
369
OK, so it is worth using them anyway, I have actually tried using a variety of leaves from round here, none have done any harm but none produced visible tannins. However they do provide enrichment for fish...
the seed pods are persistent on the tree (over several years) so they would always be available.
Yes, I can always get Eucalyptus pods any time...
 

anewbie

Well-Known Member
Messages
1,788
I'm not sure visible tannins is important? If the fish prefer subdue lighthing you can get there with floaters and dimming the light.
 

Mazan

Well-Known Member
Messages
369
So I found some peat that just says peat "Turba" in Spanish, I suppose as nothing else is listed on the package it should be OK? I was hoping to find one that said "Turba Sphagnum" but it just says Turba...costs just over $2 for a large pack.... otherwise an aquarium shop had a very small pack of peat for aquariums by Sera costing $30!!
 

Mazan

Well-Known Member
Messages
369
That's double the price it costs here. I would pay 16€, if I were using peat at all.
Well that's typical with aquarium products here...

So on the packet it says no chemicals added. It says its made from almost completely decomposed vegetation, doesn't mention sphagnum...

Also something strange, it says its high pH makes it one of the components of substrates most used in plant cultivation... High pH?? Anyway I have put some in a cup of tap water and will test the pH tomorrow...

Also when I opened it I see it contains small pieces of white stone - what could this be??
IMG_0806.jpeg






:
IMG_0805.jpeg

Another possibility I found is this, its meant for garden ponds and will treat 4000L, I would have to order it from Quito...

 

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