ok

[apistodave]

http://s5.photobucket.com/albums/y177/apistodave/Auction Videos/?action=view&current=P1000702.mp4

 

[tjudy]

OK.... fry?

 

[apistodave]

They just laid them-but I am having some problems with viability. Their fertile but they die within a day or two.

 

[Mike Wise]

Sort of like A. elizabethae fry - 'touchy'.

 

[apistodave]

I have spawned these fish many times--but what do you think?? This is the first time I've used Sulfuric to lower Ph --I think that's the problem

Elizabathae fry arent this touchy till they start showing sexual characteristics

I got some goofy stuff going on--My water comes out of the tap at 87ppm aND 7.8. pUT IT THROUGH THE rO AND IT IS ZILCH---WITH pH OF 5.0-5.5!!!!!!!!!!!!!

 

[tjudy]

Dave... if you are using a meter to test the pH of your R/O water you are probably getting a false reading. Water with 0 TDS messes with a pH probe. Add some plain aquarium salt (NaCl), which will not affect the pH, up to about 50 mS (25 ppm) and then try the pH meter.

 

[apistodave]

Ted for that reason alone I am using liquid tests

 

[tjudy]

Hmmmm.... are you using a post-R/O filter cartridge of any kind? If so, it may need to be changed. Same goes for pre-filters.

 

[apistodave]

No carbon filters just sediment filters--I'm on a well--I have other fish spawning just fine its part of what confuses me.

I have three sediment filters on it Ted--one was layered, really packed

 

[dw1305]

Hi all,
Ted is right, you can just ignore pH in water that is very low in solutes. The reason for this is that pH is a ratio of the H+ ion donors:H+ ion acceptors, and if you have very few of these you can't get a stable reading and pH is inherently unstable. This is a problem with using pH as a proxy for acidity/alkalinity, not a problem with the water.

Because of this you don't need a strong acid ("strong" defined as "A strong acid is an acid that ionizes completely in an aqueous solution by losing one H+ ion".)
If you start with low conductivity water, the tannins and humic compounds (weak acids) from oak leaves or sphagnum peat will add both DOC and some CEC and reduce the pH by cation exchange. I think water with some tannins/DOC in it is more likely to aid fry survival by complexing heavy metals and acting as a weak anti-microbial.

cheers Darrel

 

[apistodave]

I agree--I have them on a completely different program right now

 

[gerald]

The idea of "ignoring pH" in very soft water still makes me squirm just a bit, despite my high regard for DW's expertise, but I totally agree about the importance of DOC from dead leaves, twigs, sphagnum. Research on Rio Negro fishes and banded sufish has shown that DOC is vital to their osmoregulation at low pH and low mineral concentration. Gonzales, Wood and Wilson published several papers on this. So ... Got Leaves ??

ALso, Dave -- what liquid pH test do you use for measuring in the 4 to 6 range?

And what is the fish? Pic is way too dark on my screen to ID it.

 

[apistodave]

The fish on the pic is adoketa. The other one from same type habitat is elizabethae. When I lived in the old house up the street, I had everything down to a "T". I was spawning everything. 2 years ago I moved 3 blocks downstream in the aquafier and the water changed, it was harder with a Ph of 7.9. This should not happen where I live and it kind of threw me. I changed a few things, no RO, after all it is 83 PPM out of the tap. I used peat and leaves and coulnt bring the Ph down and things werent working. So I set my RO up again but continued with the new Ph regimen, that is a mistake, I am going back to the old schedule--RO, Catappa leaves and Peat. I have a very nice elizabethae fem with eggs for two days now. I got these in Germany and are from the original stock Uwe brought back in 97. No more Ph tests, they dont read true--I didnt do it in the old place and wont do them here--I am going to get some other tests done. I live in the cascade mts and the water goes through volcanic rock, basaltic mostly

 

[dw1305]

Hi all,

I am going back to the old schedule--RO, Catappa leaves and Peat.... No more Ph tests, they dont read true.

Best of luck Dave, it would be my suggestion and hopefully it will get them back to being successful. It was reading some of yours (and Mikes) posts on "the Krib" that first got me interested in Apistogramma, when I came back to fish keeping after many years away.

it was harder with a Ph of 7.9

Interesting, was it actually harder? I ask because we have a had a lot of people finding similar things in the N. of the UK, where the pH in their tap water has suddenly become much higher, and we think the reason for this is the addition of sodium hydroxide (NaOH) by the water companies, added because of the new tougher rules on heavy metals in drinking water. This raises pH, but doesn't offer any buffering and a lot of people were adding acids to reduce the pH, and finding that the pH suddenly flipped from alkaline to very acid, once the OH- ions were exhausted.

The idea of "ignoring pH" in very soft water still makes me squirm just a bit

I know exactly what you mean, it has taken me a long time to, hopefully, fully get my head around pH and buffering, but I think I now understand it and I can visualise what is actually happening in the tank.

If you can visualise the acidity/alkalinity in terms of the relative amounts of proton (H+ ion) donors and acceptors, and their reserves, rather than being entirely reliant on their ratio (which we measure as pH) it becomes a lot easier. If you have small potential reserve of H+ acceptors and donors, (the soft water/low conductivity scenario), the pH can swing about over almost the entire pH scale, but there can only ever be a very limited change in the numbers of ions and it is the total amount of ions that is much more important than their relative ratio.

You get the exact reverse of this is in very strongly buffered alkaline water (with a huge reserve of H+ acceptors) where you need to make extremely large changes in water chemistry to effect the pH.

What pH does effect is the availability of metal ions, in water with a low pH and very few solutes, all metals are likely to go into solution and become available. This could mean that iron, aluminium, lead, zinc or copper etc. that had been bound as insoluble compounds (carbonates, phosphates etc) comes into solution, possibly at levels which are toxic to sensitive fry. This might be a problem particularly for Amazonian species that have evolved in an environment rich in iron and aluminium, but almost entirely deficient in other metals.

I think this is also were the CEC and DOC from humic compounds come in, these will complex the metals and make them less available. As Gerald says there has been a bit of work on this, but it still isn't fully understood how it works in the fish, and why NOM ("natural organic matter") works and synthetic analogues don't appear to.

If you want to search for some more papers, these compounds are also referred to as ""Dissolved Humic Substances"" <http://scholar.google.co.uk/scholar?cites=17539073771122810882&as_sdt=2005&sciodt=1,5&hl=en>

cheers Darrel

 

[tjudy]

David Boruchowitz says, "The most dangerous threat to the health of a fish is a pH test kit in the hands of a person who does not understand pH."

pH is a tough concept from a purely technical point of view, but becomes more confusing in an aquarium where so many factors affect it, and what the pH really does (or does not do) for the fish is not well understood.

I have found, after many years of trial and error, that the parameters of pH, TDS (conductivity) and hardness (KH) are not equally important to the fish (and I am talking about soft water fish here). I think that the most important factor for the physical act of egg fertilization and development is KH. If it is too high there is a poor fert rate. That is why I use R/O to breed any soft water fish. Even when the fish do not seem to care behaviorally, I get better results in low KH water.

The next most important factor in my experience is pH. If the water is soft but the fish are not breeding at all, lowering the pH usually does the trick. There are lots of hypotheses as to why this might be, and I tend to believe that a low pH's anti-microbial properties is a part of the answer. I suspect that, for some species, there is a physiological instinct to spawn in low pH. Case in point, the two Parananochromis sp. I am breeding. P. brevirostris did not spawn until the pH was dropped to 5.0. The Chromidotilapia kingsleyae from the same collecting location spawned in soft water with a neutral pH.

The least important factor, IME, is TDS/conductivity. When the dissolved solid is something relatively inert and does not affect pH or KH, there is wide range of tolerance that the fish will accept. The way I lower the pH in the Parananochromis breeding tanks is to use a pH reducing chemical (Kent Marine's pH Control Minus), which uses NaCl as the binder for the acidifying ion. When I use it in low hardness (KH) water to reduce the pH, my TDS rises from >20 ppm (>40 mS) to over 150 ppm (300 mS). The fish still spawn and behave normally. I have seen this happen with other species too: Apisto. panduro, Congo. sabinae, Dicrossus filamentosus, Nano. transvestitus and numerous tetras, barbs, rasboras and Betta sp.

 

[dw1305]

Hi all,

The least important factor, IME, is TDS/conductivity. When the dissolved solid is something relatively inert and does not affect pH or KH, there is wide range of tolerance that the fish will accept. The way I lower the pH in the Parananochromis breeding tanks is to use a pH reducing chemical (Kent Marine's pH Control Minus), which uses NaCl as the binder for the acidifying ion. When I use it in low hardness (KH) water to reduce the pH, my TDS rises from >20 ppm (>40 mS) to over 150 ppm (300 mS). The fish still spawn and behave normally. I have seen this happen with other species too: Apisto. panduro, Congo. sabinae, Dicrossus filamentosus, Nano. transvestitus and numerous tetras, barbs, rasboras and Betta sp.

Now that is really interesting, and not what I would have expected, but this is when you can't beat experience. Interestingly I was talking to a well known Bristol "L number" breeder recently and he uses an RO/HMA water mix (with Terminalia catappa leaves) at about pH6.5, but at much higher conductivities (180 - 200ppm TDS) than I would have expected.

I've never used really soft water, as even our rain-water has quite a lot of carbonate buffering here and I've always used rain water in the tanks.

Some of the most difficult to deal with landfill leachate, combined a high conductivity & BOD with a low PH, but I didn't keep fish then and we never managed to find a biological filtration method that could cope with it at all, possibly due to heavy metal availability at low pH.

cheers Darrel

 

[tjudy]

I read an article a long time ago (scientific paper) that looked at the affect of different NaCl concentrations on breeding apistos. I do not remember the title or author. It described some species of 'soft water' apistos successfully spawning in conductivities as high as 500 mS, but the pH was maintained under 7.0 and KH less than 3.

 

[gerald]

Darrel - Thanks, the concept of actual numbers of free H+ and OH- ions rather than just their ratio does help me understand. I can see how a tiny change (biologically insignificant) in actual numbers of ions can cause a BIG change in their ratio (and pH measured) when there's very few of them present.

BUT - Does that mean an obligate soft-blackwater fish is perfectly happy long-term at pH 9 (and can reproduce without a badly skewed sex ratio) if the conductivity, GH and KH are really really low?

And what about pH influence on a fish's O2 uptake, mineral uptake, CO2 & ammonium excretion, etc, etc -- or is pH not relevant to those processes when total ion content (conductivity) is really really low?

IF pH still has some fish-physiology significance in ultra-soft low-cond water (I can't quite let go of that yet Darrel) then would adding a small amount of NaCl into R.O. or rainwater (maybe 1 teasp per 10 gal = about 300 uS) help to STABILIZE pH (without actually changing pH), since Na is a top-notch proton acceptor and Cl is a top-notch proton donor?


>> DW wrote: "If you can visualise the acidity/alkalinity in terms of the relative amounts of proton (H+ ion) donors and acceptors, and their reserves, rather than being entirely reliant on their ratio (which we measure as pH) it becomes a lot easier. If you have small potential reserve of H+ acceptors and donors, (the soft water/low conductivity scenario), the pH can swing about over almost the entire pH scale, but there can only ever be a very limited change in the numbers of ions and it is the total amount of ions that is much more important than their relative ratio."

I think that the most important factor for the physical act of egg fertilization and development is KH. If it is too high there is a poor fert rate. That is why I use R/O to breed any soft water fish. Even when the fish do not seem to care behaviorally, I get better results in low KH water..[/I]

Ted - what about GH? I thought it was the Ca and Mg ions (GH) that interfered with fertilization in soft water fish, not the carbonate & bicarbonate (KH) ions?

Ted/Darrel/Dave/Josh -- This discussion is GREAT but can we change the thread title please? Maybe "Adoketa pH & Hardness" or something like that? I'd hate to lose track of a good resource like this due to a non-descriptive title.

 

[dw1305]

Hi all,

BUT - Does that mean an obligate soft-blackwater fish is perfectly happy long-term at pH 9 (and can reproduce without a badly skewed sex ratio) if the conductivity, GH and KH are really really low?

Unfortunately we are now into territory where I haven't got any knowledge, I was always interested in plants and ecology and as far as possible I avoided any animal physiology, even at school.

And what about pH influence on a fish's O2 uptake, mineral uptake, CO2 & ammonium excretion, etc, etc -- or is pH not relevant to those processes when total ion content (conductivity) is really really low? IF pH still has some fish-physiology significance in ultra-soft low-cond water (I can't quite let go of that yet Darrel) then would adding a small amount of NaCl into R.O. or rainwater (maybe 1 teasp per 10 gal = about 300 uS) help to STABILIZE pH (without actually changing pH), since Na is a top-notch proton acceptor and Cl is a top-notch proton donor?

I think this is what Ted is saying, that you can stabilize pH with NaCl, and that this doesn't effect any other parameter, and the fish themselves are as happy at 300microS as they were at 30microS. My initial hunch would have been that conductivity does make a difference, but this looks not to be the case.

When I think about it, I've actually had some very similar correspondence with planted tank guru (and "the Krib" member) Tom Barr. Tom has found a number of interesting things whilst running his "high tech." planted tanks using the EI (estimative index) method.

He initially made me think about pH and buffering, because he was using a drop checker with "bromothymol blue" indicator and a 4dKH solution as an estimate of the CO2 content of the water. The method used is to set the CO2 needle valve so the pH indicator in the drop checker is running at green/yellow. The pH range for bromothymol blue is quite small, blue at pH 7 or above green at pH6.5 and yellow at pH6 and below.

When the CO2 is turned on the pH will rapidly fall to ~pH6, as a small proportion of the CO2 goes into solution as carbonic acid, and then if the valve is set correctly for the water volume, plant mass and PAR, the CO2 usage by the plants will match the CO2 input and the drop checker will remain green/yellow. The rapid reduction of pH resulting from the dissolved CO2, doesn't appear to effect the fish, although often you would go from pH8 to pH6 over an hour or so, even in a buffered system.

The EI fertiliser addition is meant to ensure that growth is not limited by lack of any of the available nutrients.

This brings on to the other things Tom has found, notably that high levels of NO3 (50ppm and above) aren't in themselves harmful to fish, if that NO3 comes from the addition of KNO3, rather than arising as a result of the conversion of NH3 - NO2 - NO3, and also the same as Ted has found that soft water fish seem quite happy in water with high conductivity (from the EI fertiliser addition), if that water is clean and highly oxygenated (another Tom Barr finding, you can have high CO2, as long as you have enough O2, without asphyxiating the fish).

cheers Darrel

 

[tjudy]

I think this is what Ted is saying, that you can stabilize pH with NaCl, and that this doesn't effect any other parameter, and the fish themselves are as happy at 300microS as they were at 30microS. My initial hunch would have been that conductivity does make a difference, but this looks not to be the case.

I agree....

(another Tom Barr finding, you can have high CO2, as long as you have enough O2, without asphyxiating the fish).

This, I think, is misleading.... gases do not behave like solids when dissolved in liquids. In fact, gasses cannot dissolve... we just describe it that way. They are actually diffusing into the solution. A solution at a given temperature has a limited capacity to contain gas (cooler liquids can contain more). So you cannot simply increase the aeration when adding CO2 in order to increase oxygen content. We see this phenomenon whenever we add cool water to an aquarium (or even let it sit in a glass). As the water heats up excess gas is forced out of the solution and appears as bubbles all over the place. I have often wondered if the pearling of plants in a heavily CO2 injected tank is also a result (at least partly) of there being no space in the water for more diffused gas.

One of the reasons CO2 causes problems for fish is that it is MORE soluble in water than O2 is. Whenever a gas has the ability to chemically combine with another molecule in the solution (in this case CO2 is combining the the water itself), the solution can hold more of the gas. CO2 + H2O = H2CO3 (carbonic acid) O2 does not have the ability to bond with water, so it is not as 'soluble'. The attraction between CO2 and H2O forces an unequal rate of diffusion of gas into the water. That means that if CO2 and O2 are presence above the water in equal concentrations, the CO2 will diffuse in faster than the O2 will... resulting in a greater concentration of CO2 than O2. The reason we 'inject' CO2 into planted tanks is that the atmospheric concentration of CO2 is naturally much much lower than that of O2. Lakes do not acidify due to the CO2 in the atmosphere. I know many planted tank hobbyists who ignore CO2 altogether and have beautiful tanks. They grow more slowly, but the amount of CO2 from the atmosphere is plenty for aquatic plants.

Ted - what about GH? I thought it was the Ca and Mg ions (GH) that interfered with fertilization in soft water fish, not the carbonate & bicarbonate (KH) ions?

You are right... I often confuse myself, still, wrapping my brain around these concepts. I have pretty much convinced myself that when dealing with tap water (or well water, especially in the midwest) the GH (Ca and Mg) and KH (carbonate) hardness are linked. Because the prominence of calcium carbonate in the water is the source for both ions in solution. That being said, when using R/O water the addition of sodium bicarbonate should increase the KH (carbonate) without increasing the GH (Ca and Mg). The Na ion is effectively inert. But I think hobbyists have known that through conventional wisdom for years. If you need to buffer the tank from experiencing a pH drop, use baking soda (sodium bicarbonate).

Though I shudder to admit it... there is a pretty easy to follow explanation of how CO2 behaves in solution on Wikipedia: http://en.wikipedia.org/wiki/Carbonic_acid