700 liter Amazone

[Jacco]

I started an 'amazone aquarium' 3 months ago. Here are some numbers:

1.70 long, 0.7 wide, 60 high.
JBL 1500e filter (pumping around 800 l/h)
50 liters of filter sand (0.5 - 0.9 mm)
filled with osmosis water.
everyday 30 liters are changed (automaticly)
temperature around 27 C
pH 6
kH 1

Here a pic (more than a thousand words)

a nice look at an empty aquarium, wood 'wattering in' and my own created background.

Here the same but 10 weeks later (cannot see my background anymore... )

I only have a simple camera... so no pic's of the fish.

What I've got so far:
30 parachareidon simulans (wild)
20 hyphessobrycon amandae (f1)
2 microgeophagus ramirezi (wild)
4 rubrocaudatus (wild) (was a group of 18... haven't figured out why i lost them and other fish stayed oke...)
some corydoras sterbai which came as eggs with plants from a friend. (somebody have a trick to get them out easily?)

And I want to keep a group (2-3m 4-5 f) of A.bitaeniata (rio Tigre). An importer with connections in peru is currently making inquieries if he can get somebody up there to catch some... keeping my fingers crossed.

Plants... not realy my interst, but at the moment I'm still starting up and i keep more variaties than I will end with. 50-75% is coverd with floaters (this will stay), but I'm waiting for my echinodorus to grow, so I can remove some other plants.

I still want to play with the placement of the wood. So I haven't added any leaves yet (beech, oak etc.)

My dilemma's:

My current (luxary) dilemma, I've found some beautiful dicrossus maculatus (wild). And am wondering in what ratio (male:female) to keep them and if 2 males would keep each other alife. Is 2m 3f a livable group?

the pH of my aquarium, eventhough i've got it file with osmosis water I have trouble to get it to around 5. Peat doesn't do the trick (unless i use 50 liters of it maybe and where to place it...) I used some acid (H2PO4) for the time being, but would like to use something beter. Any suggestions?

Well this is it so far, looking forward to your comments.

 

[raymond82]

Very nice tank!! I would love to have a tank that size to be able to have a group of apistogramma's and see them interact.

When I use peat to filter osmosis water the pH lowers quite well but usually I'm dealing with small volumes. I do have the feeling the water should really interact with peat for the pH to lower, just hanging peat in a bucket doesn't do much for me. In other words, putting the peat inside a filter and letting the water run through is more effective. Sometimes when I need low pH water quickly I boil some peat in RO water. This gives water with a pH as low as 3 which I then mix with normal RO water again. However, this may not be very useful for the quantities you need. Anyway I think the easiest way to use peat is in a bucket before you add the water to the aquarium.

 

[regani]

beautiful looking tank!
where is your pH at the moment? if it is not too far off it may be easiest to keep it where it is. if the fish feel happy enough you may not need to go down to 5 unless you want to some of the species in there?
the phosphate you use to lower the pH will cause trouble in the longer term as it will lead to problems with algae. it may be better to hydrochloric acid or sulfuric acid. another alternative that I have used successfully is citric acid.

 

[Jacco]

@ regani: thx, pH is round 6 right now. I thought at this pH there should be virtually no PO4 available, just H2PO4. But I'm new at this . Too much PO4 is certainly not what i'd like . Citric acid can be organicly decomposed I read somewhere, don't know if this is harmfull for the balance of the waterquality? So HCl and H2SO4 are probably "best" as you stated.

@ raymond: thx too, nice to see some amsterdam here I've got peat (4 liter) in my filterroom in the back corner of the aquarium, it turned my water into an english blend tea... but lowered the pH only by aprox. 0.1... Boiling is a nice tric! Not for my quantities but i didn't know this.

An other question: Does anybody know why adding acid (like HCL, H3PO4 and H2SO4) highers the conductivity, while lowering the pH with peat doesn't have this effect?

 

[regani]

'phosphate' in water actually exists mostly as hydrogenphosphate (HSO4)2- over much of the pH range, the 'real' phosphate exists in larger amounts only at very high pH (>11), dihydrogenphosphate (H2PO4)- forms the majority of of ions only at very low pH (<3). so, regardless of which form of phosphate you put in, at most pH values in an aquarium, there will always be plenty of hydrogenphosphate around useful for bacteria (and plants).

I have used citric acid (together with HCl) for the past 18 months or so and have seen no negative effect on water quality or fish.

in a nutshell: conductivity in water depends on the availability of free ions, pure water actually has almost no conductivity. like salts strong acids dissociate completely into ions (e.g. H+ and Cl- in the case of hydrochloric acid) and and increase the number of ions in solution, therefore contributing to the conductivity.
humic acids dissociate as well (if not as easily), but also have the ability to 'capture' some of the cations present in the water as complexes. these captured ions (complexes) can't contribute fully to the conductivity anymore and therefore conductivity is not affected to the same degree as with strong acids.
some other organic acids also possess this ability, which is the reason why I use citric acid. if the conductivity is not too high you can actually see that the addition of citric acid lowers conductivity.

 

[merlin]

In what format do you buy citric acid.(powder or liquid) Is it an over the counter product. What name.

Derek

 

[regani]

Hi Derek. you can buy citric acid as crystals/powder from some food supply or soap making shops (it is used as food additive and in the making of soap). for dosing I usually make up a 30% solution in water as I find liquids easier to handle than solids.

 

[Jacco]

Thx again regani, you obviosly payed better attention at chemistry than I did In the netherlands its considered not done to use acid so i havent found a good recipe yet. In what proportions do you use citric and hydrochloric acid?

 

[regani]

I use about 2:1 ~14%HCl (diluted from the commercial 28% I can buy here) to 30% citric acid. you have to keep the solutions separate, though, as the citric may go off over time when kept with the HCl.
I use the HCl because our tap water here is fairly hard (kH ~18, GH ~6, ~650 uS conductivity) and a bit basic (pH 7.6-8) and HCl has a stronger effect on pH. so I dilute ~50% with rain water, then add HCl and then citric. I use about 12mL of the 14% HCl and 6mL of the 30% citric in ~200L of water. this brings if to a pH of about 6.0 and ~120 uS conductivity, which I use for most of my tanks.
I have used other ratios as well and also just pure citric acid. the amounts added will of course depend on your water. just experiment a bit to see what you need to get to where you want your water to be.

but as your pH is at 6 already and you use RO water you will not need much.

 

[Jacco]

Actually the pH of my RO water is 7.5. I lowered it with acid over time (20 ml of 75% phosporic acid)

 

[dw1305]

Hi all,

Does anybody know why adding acid (like HCL, H3PO4 and H2SO4) highers the conductivity, while lowering the pH with peat doesn't have this effect?

Have a look here: <http://www.apistogramma.com/forum/index.php?threads/sphagnum-moss.12164/>, but basically it is because of ion exchange, the humic acid (acids are defined as H+ donors) binds the positively charged calcium (Ca 2+), magnesium (Mg2+), potassium (K+) ions, and exchanges them for positively charged hydrogen ions (protons - H+). This decreases the pH (acids are defined as H+ ion donors), and also the conductivity (metal ions conduct, protons don't) .

Weak solutions of strong acids (like HCl, H3PO4 and H2SO4), disassociate fully and the anion (PO4--- etc) raise conductivity. If you want to experiment a weak acic like citric acid (C6H8O7) doesn't disassociate and will reduce both pH (it is an H+ donor) and conductivity (possibly by chelation? I'm not sure).

The use of citric acid in aquaria is usually avoided because supposedly its "decomposition leaves gummy residue on the equipment and substrate", but I'm not convinced by this and I think it should work quite well.
I've tried it in a planted tank (more as a carbon source than as a pH/conductivity reducer), and it didn't seem to cause any problems.

cheers Darrel

 

[Jacco]

Thx! Read the other threads now and again got a little wiser

 

[Josh]

Just wanted to say, gorgeous tank. Nice work

 

[regani]

I haven't seen any residues or similar problems with the citric acid. citric acid is actually an intermediate product in the energy production of most cells (Krebs cycle) so many organisms will be able to process it, resulting products are 'energy' and CO2 - that was one of the reasons I picked it. the other is that of all the organic acids citric acid is one of the stronger ones.
the reduction of conductivity does work through chelatio. chelation and complex formation/complexation are the same thing (more or less).

(metal ions conduct, protons don't)

just a small correction here. you don't need metal ions to increase conductivity, H+ does the trick as well. this is the reason why e.g. HCl added to water increases the conductivity. all ions added will increase the conductivity - unless other factor such as complexation/chelation come into play.

 

[dw1305]

Hi all,

just a small correction here. you don't need metal ions to increase conductivity, H+ does the trick as well. this is the reason why e.g. HCl added to water increases the conductivity. all ions added will increase the conductivity - unless other factor such as complexation/chelation come into play

I'm not a proper chemist, so I did wonder why H+ ions "don't conduct" and pure H2O is an electrical insulator. I know that you don't really have 10-7 H+ & OH-, but that two water molecules form one hydroxide anion (OH−) and one hydronium cation (H3O+), and I've just found out, via the wonders of Wikipedia that water does conduct electricity, but only at a very low level:

Chemically pure water has an electrical conductivity of 0.055 µS∙cm−1. According to the theories of Svante Arrhenius, this must be due to the presence of ions. The ions are produced by the self-ionization reaction
H2O + H2O

H3O+ + OH−

So are we saying that protons (H+) conduct much less electricity than other cations, or have I still got the wrong end of the stick?

cheers Darrel

 

[dw1305]

Hi all,
I should also said both it is a really nice tank and I've now read Regani's excellent post on citric acid, which I seem to miss when he posted it.

cheers Darrel

 

[regani]

to have conductivity in a material the charge (e.g. form two electrodes) will have to be able to 'move around'. in solids these are usually the electrons that do the job. but to be able to do that the atoms need to be bunched up close together as it is the case in most solids, otherwise the electrons can't jump across the gaps. the metals are a special case here as in a metal the electrons are not fixed to one atom but can move around relatively freely and hence can carry charge from one end of the metal to another, which is the reason why metals are generally good conductors.

in liquids the atoms (or molecules) are further apart and less ordered which makes it impossible for the electrons to carry the charge across the liquid, so pure liquids are usually insulators. this changes if we can introduce ions into the liquid as we can do in water. in a very simplified version you could say that the ions now move around towards the respective electrodes and carry the charge and make our solution a conductor. any ions will be able to do this and you can look at HCl basically as a 'salt' similar to NaCl, which dissociates to give the ions H+ (which will form H3O+ in water) and Cl-

a more accurate model is to look at the water molecules. they are dipols and will aggregate around any charges and they also form what is called 'hydrogen bonds' which each other. this basically means that a water molecule (H2O) shares it's hydrogens (H) to a degree with it's neighbors. the addition of ions 'loosens' those hydrogen bonds. now, when a charge is present it is not the big ion that has to move around trying to get to an electrode, but the water molecules can just very quickly 'swap' hydrogens to transport a charge.
an analogy may be a very crowded square that you are trying to cross with a box in a wheelbarrow. it will be slow going as you will have to push everyone out of the way to get across. if on the other hand you give one person on your side the box and ask them to just pass it on until it gets to the other side, this will get the box there much quicker.

because of that 'hydrogen swap effect' the addition of acids (or bases) has such a big impact on conductivity, much the same or even bigger as for salts.

I hope the above makes sense? I tried to avoid getting too technical.

 

[dw1305]

Hi all,

I hope the above makes sense? I tried to avoid getting too technical.

No, I think I've got it. I can see that for a solution of NaCl (disassociated into Na+ and Cl- ions) you would have approx. linear relationships between weight of salt added, electrical conductivity and specific gravity of the solution.

The same then for a strong acid (solution), it would have lots of H+ ions fully disassociated (this is shown by the acid dissociation constant, Ka) and a high conductivity. This large density of protons would mean the hydrogen swap effect was pronounced and electrical conductivity was high, but in this case they would contribute little mass (because of the RAM of hydrogen 1M sol of H = 1g in 1000g, and the Cl RAM = 35.5).

I've just looked it up - 10% HCl ~ 3M HCl density = 1.048

So it doesn't matter what the ions are, more of them will conduct more electricity, unless solid compounds are formed that precipitate out (removing ions) or ions are complexed/chelated (like they would be by EDTA or humic compounds).

cheers Darrel

 

[regani]

that's it

 

[Jacco]

today i got the biggest compliment one can get as a fish keeper: fry !
guess 3 times which fish:
No not de maculatus, nor the ramirezi, but the paracheirodon simulans. There is at least one swimming in between my floating plants of about 8-10 mm long. Fascinating to see it already has it's blue stripe. Just had to share this. I'll have to find a camera and post some pic's... eventhough it's not apisto fry