# Water hardness



## Zarathustra (Nov 9, 2003)

Discuss buffers from the market allegedly siften the water, yet, they do so by adding solids to it. Using a colometric GH reading, indeed, after adding this buffer, the reading shows that it soften the water, yet, the TDS measurment from conductivity increases in Siemens due to the added solids.

It is my understanding that soft water is important to Piranhas since it equates their environment thus similates their osmoregulation in nature. The question is: WHAT IS THE MEANING FOR FISH OF TDS AS OPPOSSED TO GH AS IT RELATES TO OSMOREGULATION/That is, I imagine that TDS is the true measurment meaningful to osmoregulation, as oppossed to just calcium/magnesium measurment, which is the value associated with GH. If so, Discuss buffers, and all related products only mis-guide us by blindsighting a reading that is meaningful to fish. In Summa: Do fish systems really differentiate GH from TDS, or is the true meaningful reading TDS as oppossed to GH as it pertains to fish health/osmoregulation???

Anu guidance, or suggested reading on this subject?


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## hastatus (Jan 16, 2003)

Topic moved to appropriate forum.


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## Zarathustra (Nov 9, 2003)

Thanks! I noticed that after and re-wrote the question under the right category. In the future, can i move it, or is it up to you guys?

Order and read the Los Peces Cariba...Great book!

RGDS


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## Piranha_Adept (Feb 11, 2004)

To the best of my knowledge. Peat is the best thing to use. The other softeners only manipulate the Calcium, and Magnesium content. It's true they drop the percentage. Thus changing one form of hardness, but they also increase the sodium content. Sodium is conductive. That is probably what you are seeing with your reading. When one thinks logically. How can a substance be added, and total added substances be reduced???

Peat or the reverse-osmosis unit are the best for truly softening the water for discus and piranhas. But this is just my opinion. I will follow this tread to see what the specialist come up with. Some people cut 50% distilled water with 50% tap. Depending on tank size and amount of water changes. The distilled water method can become costly.


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## DonH (Jan 25, 2003)

I have never used Discus Buffer but I'm pretty sure it is a phosphate buffer (most likely sodium biphosphate) that also precipitates calcium and magnesium to soften the water. Thus, measuring GH will yield a lower value but TDS will still be present due to the added sodium. Without altering water parameters, TDS (total dissolved solids) is usually not a problem in raising piranha unless you slack off on maintenance and just top off your tank. Evaporation will slowly increase the mineral content of the water so the only way to alleviate the problem is through water changes.

Distilled/Reverse Osmosis water and peat are two ways to both soften water (without increasing TDS) and lowering pH. They do it through two very different methods though&#8230; Using distilled or r/o water will dilute the mineral content while peat acts more like an ion exchange media by swapping ions of calcium and magnesium for hydrogen ions (H+). The extra H+ ions will lower pH while hardness (Ca2+ and Mg2+) is taken away.

As for osmoregulation, without making this into a long biology lecture, you have to understand osmosis first. Osmosis, in the case with freshwater fish, is the movement of water through a semi-permeable membrane (the skin and gills) from a solution of lower solute concentration (the water) to a higher solute concentration (the fish). This means that a fish is constantly taking up water into the body and thus must be able to get rid of it. This is done by expelling excess fluid in the form of urine. That's why fish that have kidney disfunction will bloat up (dropsy) due to retained fluids.

Back to the main question about TDS vs GH in osmoregulation&#8230; Since osmosis is determined by solute concentration, elements of GH does factor into that but you need to look at TDS to get the complete picture because there's more to a solution than just calcium, magnesium, and to a lesser extent, iron, manganese, and aluminum.

So is everyone asleep yet? lol


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## Zarathustra (Nov 9, 2003)

So indeed, TDS is what truly matters mostly in osmoregulation, and when looking for soft water conditions related to fish, the conductivity reading, as oppossed to colormetric reading will guide us better (since we are not making soap!)?

Does softer water (from now on, meaning los TDS), make it easier for Piranha's to have proper kidney functionality?

Ro/distilled water mix is truly the right answer then. As far as peat, it seems it does not lower the TDS, but the tannic acid content lowers the PH...or does the ion exchange resulting from peat gets rid of solids from the water? How do ion exchange resins play a part on this matter?

Lastly, when adding salts for treatment, it increases substantialy the TDS, thus after treatement, it seems paramount to lower the TDS back to normal, otherwise we can blow the Piranha's kidneys?


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## DonH (Jan 25, 2003)

It's actually more difficult for a fish to osmoregulate in water that's low in TDS. Think about it... Water that's low in TDS is very low in solute concentration which means that more water will be entering the fish's body through osmosis. That means that a fish will have to work harder to expel these fluids. Fortunately, millions of years of evolution has given these fish very efficient kidneys just for this purpose.

As far as treatment, I think you have it backwards... When a fish is stressed, sick or has an open ulcer, it needs every bit of help it can to recover. Salt aids in osmoregulation by bringing the water's solute concentration closer to the fish's body concentration. Thus, reducing the fish's need to expel excess fluids and taxing the kidneys. Once again, these are FRESHWATER fish and after the treatment is done, the salt should be removed through water changes.

From what I understand, peat retains the calcium and magnesium ions as it releases hydrogen ions into the water (thus the ion exchange to soften AND lower pH). That's why peat must be replaced every so often in order to keep these properties.

Finally, there aren't that many hobbiests who would monitor TDS. The equipment is more expensive than a standard GH test kit and most would probably not know what it does anyway. Knowing the GH of your water is acceptable enough for piranha keeping in my opinion.


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## serrasalmus_collector (Mar 9, 2003)

Rocking topic.. Great answers...


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## Zarathustra (Nov 9, 2003)

Indeed your logic is sound, and higher TDS demands less effort to osmoregulate, thus fish's systems in low TDS water do have to work harder to do so. However, given that these fish do live in such soft water (average rainfall in the Amazon throw "distilled" water in copius amounts!), I wonder if thier systems are not configured to work in such conditions.

If we follow the logic that it is actually better/easier for kidneys to work with more levelled, that is, closer osmotic pressure through semi-hard water, then we would, and maybe should, conclude that it is better to keep Piranhas at higher TDS than their natural habitat. I am not being facetious. The fact that animals/humans lived in certain conditions does not mean that there are not better ones...may it be that harder water, say 300 PPM (16/17 GH) is actually better for pirtanhas?

The measured hardness taken at various part in the Amazon indicate variances from 3GH, to 12 GH depending on where it is taken. However, I have been there during rainy season and boy, does it rain!; and prior to it. I can't help to think that the hardness must go through dramatic changes...from high, after the dry season/evaporation specialy in the "cochas" (small lakes), to the torrential currents/rivers resulting from heavy rain, whereby the hardness is probably very low. Do you know whether the water testing done, and thus recomended has been done during rainy or dry season?

As far as salt is concerned, indeed, the recomended dosage for treatment is off course way to high to keep them as such for long periods of time, thus I do think it is essential to remove after treatment...

Incidentaly, Siamese fighting fish seem to do better with 1 /4 to 1/2 tblspoon per gallon..yet, I don't do so with the pirahnas...


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## serrasalmus_collector (Mar 9, 2003)

Zarathustra said:


> may it be that harder water, say 300 PPM (16/17 GH) is actually better for pirtanhas?


 OMG... I don't truly know how to answer that question. But I myself keep my piranhas GH between 5dH and 7dH normally, and keep it between 1dH-3dH for breeding. I don't think that high of a parameter will hurt the fish, but chances are it's nothing like the native biotope. There may be some stress, but sooner or latter they should adapt.

The GH can effect the overal matabolism of the cells. High GH will deffinately effect spawning. I breed fish, and try to keep my aquariums as close the the native biotpe as possible.


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## Zarathustra (Nov 9, 2003)

Do you think that they are more prone to breed at low GH since it coorrelates to the rainy season, that is, to a lower GH as a result of rain...see, I don't know if Piranhas, like discuss, have a season where they breed in nature, and if it relates to rain??? (and again, I from now on always think of GH in terms of TDS, since, as discussed, GH as calcium/magnesium only, makes no sense for osmoregulation).

Also curious about your quote: what has your experience being about shaoling serrasalmus?


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## serrasalmus_collector (Mar 9, 2003)

Zarathustra said:


> Do you think that they are more prone to breed at low GH since it coorrelates to the rainy season, that is, to a lower GH as a result of rain...see, I don't know if Piranhas, like discuss, have a season where they breed in nature, and if it relates to rain??? (and again, I from now on always think of GH in terms of TDS, since, as discussed, GH as calcium/magnesium only, makes no sense for osmoregulation).
> 
> Also curious about your quote: what has your experience being about shaoling serrasalmus?


 Well in the wild they breed during the rainy season. There are many simularities to discus breeding, and breeding wild piranhas. I choose to duplicate nature, and it works for me.

An increase in fresh water, drop in GH, shift from low to higher ph, and a few other tactics I use on wild piranhas. If you have breed discus you probably use simular tactics.

As for shoaling serras. That's my kick. I like to keep quantities together in a small tank, and then explore breeding them. There is always a threat of canabalism, or life threatning aggression with the serrasalmus species. But, I appear to have defied some odds. I currently have 10 S.Maculatus and 1 SB spilo in a 100 gallon tank. 2 eigenmanni and 4 maculatus in a 45 gallon tank. 4 red throated spiloCF's in a 75 gallon tank, 7 S. Gery in a 100 gallon tank. And some pygo shoals.

All fish other than the spiloCf's have been together for a minimum of 6 months. I can't understand why they continue to shoal, but I dig it. Perhaps it's my water parameters. I have my personal beiliefs why the stay together. But untill I can breed more, and then aquire more serras; this is just a hypothesis.

Defying the odds, and comming out tryumphant is my greatest pleasure in the piranha hobby. There are some pics of my shoaled serras on this forum.

Macs and SB spilo.

eigenmanni and maculatus

S. Geryi

I don't want to ruin the water parameter topic, but there are a few of my still shoaling colonies...


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## Zarathustra (Nov 9, 2003)

It makes sense that they breed during the rainy season when the TDS would be lower...

As to the shoaling of serras...I have had 24 spilos and two rbp, 2 to 3" together in a 144 gal tank and seem to be doing OK, except for fin bites...will see as they grow...but i do believ in attempting and experimenting...though it seems by the very different results that it is a highly individual experience and is tough to make generalizations or predictions...


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## serrasalmus_collector (Mar 9, 2003)

Good Luck!!! I love to hear, and see others with serrasalmus shoals... Just keep a watchful eye. If you have success and keep them for long periods of time, you will learn so much more about the individual personality of your fish.


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## Zarathustra (Nov 9, 2003)

For now, it seems OK, but the two RBPs that I have there are growing so much faster that they are sterating to become a problem...I might have to take them out and leave only the spilos...

These are solid 3" now..do you think is too risky to put them in with my 9" Piraya/Ternetzi and RBP, plus 2 5" RBP, and a 6" Cariba" in a 115 g tank?


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## Piranha_Adept (Feb 11, 2004)

Well all fish have a personality of their own. But to place reds with other wild pygos 3 times larger is just asking for serious trouble. The reason I use wild is based on the captive breeding history of Ternetzi and Piraya. I honestly don't think the 3 inch reds will make it through the night. I have had problems with piraya all the same size. Piranhas like wolves build a pecking order. 3 inch won't pass the test with 9 inch fish. Simply placing them with captive 9 inch reds would be a problem.

But the final choice is yours. If you put them together they must be monitored until the babies reach about 5 inches. And this is 24 hour monitoring. Perhaps you can place a barrier in the spilo red group. Feed the spilo's on worms, and shrimp. Do 2 small water changes a week, and perhaps in a few months they may pump up in size.


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## Zarathustra (Nov 9, 2003)

Thanks...will probably wait for the 5"...at the rate these are growing might be only a few months!...but, what happends in nature, do the big ones eat the small one often???


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## DonH (Jan 25, 2003)

Let's not derail this thread... There's good info regarding water chemistry. If you want to discuss piranha aggression or breeding, please start another thread in the appropriate forum. Thanks.


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## Zarathustra (Nov 9, 2003)

Agreed Donny...thanks for keeping us in check.

Do you have any feedback on my last posted question: whether it may actualy be better for Piranhas' kidney function to have harder water based on logic?

Also, isn't the water in the dry season much harder than in the rainy season? Do we know how different the hardness readings are in the natural habitat between rainy and dry seasons? I would imagine that low is better since in their nature dry means danger, maybe even death, and they spawn on softer water...but mine are conjectures, are there any factual studies?


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## DonH (Jan 25, 2003)

In a healthy fish, you do not need to adjust water parameters just to ease osmoregulatory stress. They are "designed" to function in soft water. You can't take TDS and relate it just to osmoregulation. This parameter, along with GH can affect growth, color, and their immune system. True, they are very adaptive fish, but if given the choice, I would keep the water soft. Unfortunately, I don't have the choice... they'll just have to be happy in liquid rock. lol.

As far as their native habitat, that's out of my area of expertise... You'll need to ask Frank (hastatus). He might be able to give you info or direct you to more literature.


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## Zarathustra (Nov 9, 2003)

I hate to drill the issue, but are we in agreement from the above discussion that soft water means truly low TDS? Since you can get a low reading from discus buffer but high TDS?

Also, do you mean that you don't have the option to keep water soft since where you, as it is my case, the water is high? How about mixing it with RO water? How hard is your water? Have you noticed any adverse effects?

All and all I agree, that ideally, we ought to emmulate, as much as possible, their natural habitat always!


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