# Can anyone help...ph question



## michael woods (21 Apr 2014)

Ok so I'm about 4 weeks into my first aquascape and the tank is nearly cycled...showing 0.25 ammonia and 0.25 nitrite with 10ppm nitrate. I'm running an ei dosing schedule with a 50% water change on Sundays. It's a 64 litre tank with a pressurised co2 system pumping around 2bps and no fish in. But, when I got my water tested today my PH came back as 6. Unfortunately I don't know the kh and gh so I was wondering whether this low ph is detrimental to the tank? I'm trying to grow a dwarf hairgrass carpet which is showing encouraging signs of growth and there are 2 pogostemon helferi and 2 ludwigia glandulosa (going in on Thursday). My drop checker is a nice lime green so I figure there's enough co2 in (running fluval 106 external canister and a hydor koralia 900 powerhead) and enough flow but I'm just a bit worried about the ph level as some threads on here say to forget about the ph and others have said the cycle crashes below 6. So if anyone can help if hugely appreciate it.  It may also be worth noting that I intend to put around 5 amano shrimp in and I read that soft water isn't good for their exoskeleton. So please, help me out?

Cheers, Mike


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## Alastair (21 Apr 2014)

Ph 6 or below has never affected any of my newly set up tanks or the cycle process. My current tanks ph was 5.6 cycled as normal


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## michael woods (21 Apr 2014)

Really?? Again it was various other forums and my lfs that said below 6 will stall the cycle so I went out and bought some coral sand and media bags but I was a bit hesitant about putting it in so if there are people out there who have cycled and run a tank with a ph lower than 6 then I'll take the coral sand etc back! Thanks for your reply


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## Lee Sweeting (21 Apr 2014)

I've never had any ill effects, and my pH is currently 6.0.


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## Alastair (22 Apr 2014)

michael woods said:


> Really?? Again it was various other forums and my lfs that said below 6 will stall the cycle so I went out and bought some coral sand and media bags but I was a bit hesitant about putting it in so if there are people out there who have cycled and run a tank with a ph lower than 6 then I'll take the coral sand etc back! Thanks for your reply



A lot of fish shops are still on the belief that all fish are to be kept in ph 6 to 7. I remember telling a guy in a shop I was buying some chocolate gourami from when he asked what my water was like and I told him it was around 5 and a half and he looked at me like I was clueless and like you, saying I need to buy some crushed coral. 
After telling him what the fish true habitat is like water etc he looked confused as I said thanks and left. 
After that now, when he knows he has them coming in on a shipment he sets up a tank specifically for them also with leaf litter etc low ph and they are really colourful and happy.


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## Lee Sweeting (22 Apr 2014)

michael woods said:


> Really?? Again it was various other forums and my lfs that said below 6 will stall the cycle so I went out and bought some coral sand and media bags but I was a bit hesitant about putting it in so if there are people out there who have cycled and run a tank with a ph lower than 6 then I'll take the coral sand etc back! Thanks for your reply



Like Alastair i also keep soft water fish, what people don't realise is that ammonia is ionized form (ammonium) at low Ph values, which is drastically less toxic to fauna. The biochemical activity in your filter may be a little low, but any nitrogenous compounds that are present are much less toxic than in buffered water.


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## EnderUK (22 Apr 2014)

michael woods said:


> I read that soft water isn't good for their exoskeleton


 
Not directed at you, just quoting 

Can you call your water soft if you dose EI?
My tap water is 75 TDS pretty damn soft water.
I do a 75% W/C and that gets my tank to around 200 TDS
By the end of the week it's around 375 which if I was taking that out of the tap I wouldn't call it soft water. I dose with KNP+Trace and Mg since my water already has 20ppm Ca. I know EI has no direct effect to "soft water" fish.

My low tech shrimp tank I threw in some oyster grit which has brought the ph up to 7 for my nerite snails. I don't think I would do this with my high tech tank as the TDS would shoot up even more but you could do that if you want to add some more calcium to the water, or you could just add it direct as a salt. Once the last of my glass shrimp kick the bucket I was planning on adding amano to my high tech, I might start adding a bit of Ca salt then if they do need it.


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## RichardJW (23 Apr 2014)

Alastair said:


> Ph 6 or below has never affected any of my newly set up tanks or the cycle process. My current tanks ph was 5.6 cycled as normal


Like Alistair I'm very lucky in that our tap water comes out of the pipes in quite a soft state - can quite understand that shrimps ( and snails ) would not thrive in a low Ph environment without some access to source Calcium for their exoskeleton . Conversely both these creatures exist naturally in low Ph - any problems we may encounter may be because of the specific species that are prevalent in the hobby . What's the bet that those in hard water areas like London don't have these issues ( unless they use RO )


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## sciencefiction (26 Apr 2014)

There is a difference between soft water and low Ph.

Two tanks with the same Ph can have totally different other stats. For example I now have two tanks both with a Ph of 7.4, but the TDS in one is 200, in the other 500, Gh in one 7, in the other 14. You can have a low Ph tank with hard water too. So for anecdotal evidence it's best to provide all readings to make a conclusion.

Low Ph can be because one injects CO2 or some other factors but there could be enough minerals to support the life of the fish/inverts.
Or low Ph because the Kh has dropped to 0 and no longer buffering the Ph, in which case your fish will struggle to survive. No matter the Ph they need it stable and not fluctuating with water changes or for lack of buffering.

If the Ph is low because the water is soft but keeps stable at certain value then as long as you keep soft water species you are ok.

And in terms of cycling a tank with such a low Ph, it's the plants that take up the ammonium in such environment because nitrification is inhibited. Go try a fishless cycle in a tank with no plants with a Ph of 6 or below, it won't happen or will take you half a year to cycle such a tank.  Yes, ammonia is in its non-toxic ammonium state in such enviroment but with no plants to take it up where will it go, disappear?

So I agree, no problem cycling a planted tank with low Ph. But if I have soft water I'll make certain I know the rest of the stats to make sure I don't have a possibility of a getting to a 0 Kh and possible crash in the system.


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## ceg4048 (26 Apr 2014)

sciencefiction said:


> Or low Ph because the Kh has dropped to 0 and no longer buffering the Ph, in which case your fish will struggle to survive.


Which is not really true. Amazonian fish actually breed when the pH drops to very low levels. Fish really do not care about pH as an arbitrary number. It has to be within context of other factors. In the rain forest, tannic acids and humus leach from the leaf litter during rain. The leached products, including acids, in combination with other factors, such as temperature and so forth, drops the pH of the waters to very low levels. This typically triggers the onset of breeding.

I have absolutely no difficulties whatsoever cycling a low pH tank. Nitrification is not inhibited because there are lots of species in the sediment and media to perform nitrification under a variety of conditions.

I think folks really need to forget about low pH because neither fish, nor microbial community, nor plant actually care. They only care about the reasons that pH is low. More people kill their bacteria by their addiction to adding ammonia when starting a tank, than any due to low pH.

Cheers,


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## sciencefiction (26 Apr 2014)

ceg4048 said:


> Which is not really true. Amazonian fish actually breed when the pH drops to very low levels. Fish really do not care about pH as an arbitrary number. It has to be within context of other factors. In the rain forest, tannic acids and humus leach from the leaf litter during rain. The leached products, including acids, in combination with other factors, such as temperature and so forth, drops the pH of the waters to very low levels. This typically triggers the onset of breeding.
> 
> I have absolutely no difficulties whatsoever cycling a low pH tank. Nitrification is not inhibited because there are lots of species in the sediment and media to perform nitrification under a variety of conditions.
> 
> ...



I am not sure why are you pointing out my statement..  I am not talking about the number of the Ph, I am talking in a Kh of 0 the Ph will drop. Now if one starts out with a low Ph because of the fish requirements and keeps it that way constantly, then it is a different story. But if water changes or possibly addition of fertilisers such as Mg and Ca bring the Kh back up and in turn raise the Ph, then these are fluctuating conditions and fish will get sick or die.

In terms of no problem cycling a tank with low Ph, you are talking about a planted tank where the sediment is alive, plants take up ammonium, etc..... In that scenario it doesn't matter I agree, but I gave an example for a non-planted tank. You only need to try cycling a tank with a Kh of 0 and Ph below 6.5 without plants and is very easy to prove what I am trying to say above.



> More people kill their bacteria by their addiction to adding ammonia when starting a tank, than any due to low pH.



I agree to disagree.
The levels added to a tank for fishless cycle are below what kills bacteria. I dose 3ppm max.  I've cycled planted/unplanted tanks using with ammonia, no problem whatsoever. It hasn't killed the bacteria but has cycled the tank instead in the same amount of time you'd cycle with plants with that difference you can fully stock the tank at once.


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## ceg4048 (28 Apr 2014)

sciencefiction said:


> I am not sure why are you pointing out my statement.


I'm pointing out your statement because it is incorrect. You stated that the inability to prevent the pH from falling is a dangerous situation and clearly that's not true as I pointed out in the natural system. So people need to understand that they really ought not to unilaterally find ways of controlling pH without first understanding the WHY of a tanks pH. My fish breed at very low pH, and in fact, sometimes it's the only time that they will breed easily.

You can disagree all you want, but I don't use ammonia and I don't have any trouble with low pH. I really don't care how fast you stock your tank. I am not in a race and I see the big picture. My fish breed, are healthy, don't have weird problems, the tank has no trouble, no algal blooms and nothing untoward. I use this same procedure regardless of pH. I'll continue to warn people against dumping toxic disinfectant into their tanks. Just because the fish survive your throwing them into an unstable tank, it does not mean that there has not been any damage to their systems. You can easily damage their gills or respiratory system and, at a later stage, they will be more susceptible to other problems that occur in the tank. Many unexplained deaths and diseases are attributable to too-early introduction of fish to the tank.

Cheers,


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## sciencefiction (28 Apr 2014)

ceg4048 said:


> I'm pointing out your statement because it is incorrect. You stated that the inability to prevent the pH from falling is a dangerous situation and clearly that's not true as I pointed out in the natural system.
> Cheers,



There is a bit of misunderstanding. If that's how my statement sounded to you then I was wrong explaining myself and I apologize. I am not very good at explaining myself.
You quoted the following statement:
_Or low Ph because the Kh has dropped to 0 and no longer buffering the Ph, in which case your fish will struggle to survive. _
However, there are a few more sentences in regards to this just after the single sentence you quoted:
_No matter the Ph they need it stable and not fluctuating with water changes or for lack of buffering.
If the Ph is low because the water is soft but keeps stable at a certain value then as long as you keep soft water species you are ok.
_
What I meant by it was really that a fluctuating Ph is dangerous, such as a sudden rise or sudden crash. If the Ph dropped or rose slowly overtime than it's a different story because it gives the fish time to adjust to it.



ceg4048 said:


> Just because the fish survive your throwing them into an unstable tank,it does not mean that there has not been any damage to their system



I think this is another misunderstanding. I don't dump ammonia into the tank when there are fish in there. Hence it's called fishless cycling.  You do it prior to introducing fish for a period of time until about 3ppm ammonia each day is converted to nitrAtes in 12-24 hrs and like that for a week to make sure it's fully cycled. Then a large water change is performed to remove the accumulated nitrates if there are no plants, and you add the fish.  During cycling I test the equipment, decorate, plant the tank, etc..After a fishless cycle the tank is extremely stable. You won't see an ammonia or nitrite reading ever in such a tank after stocking unless your filters fail, you dump all the food at once, or some other reasons out of your control.

People dump other "disinfectants" in the tank that are harmful to fish such as liquid carbon, and have killed fish with accidental high doses of CO2 too quite often. Not all high tech tank keepers but a lot of them don't even have the same fish for 6 months at a time.



ceg4048 said:


> My fish breed, are healthy, don't have weird problems, the tank has no trouble, no algal blooms and nothing untoward



It's funny, because I can say the same about mine. Although my tanks are not as beautiful as yours because I keep them a bit simpler due to lack of time or finances.

And I had weird problems such as my 2nd hand old tank developing a leak, my filter developed a leak and poured half of a 5f tank water on the floor, the drivers of the LEDs got bust because they were cheap and low quality, in another tank the lights were replaced by the seller 5 times due to a manufacturing fault, tank stayed with no light every so often the plants went to shits.

But yeah, besides this I haven't had much problems recently.


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## sciencefiction (28 Apr 2014)

sciencefiction said:


> What I meant by it was really that a fluctuating Ph is dangerous, such as a sudden rise or sudden crash. If the Ph dropped or rose slowly overtime than it's a different story because it gives the fish time to adjust to it.



Just to elaborate on my own statement above. And also to add I am not trying to teach anyone anything just explaining myself because I feel misunderstood.

 I don't mean a sudden change in Ph caused by a CO2 injection which has no effect on the fish. I mean change caused by the Kh suddenly zeroing and pulling the Ph down in a day or a sudden rise in Ph in a soft water tank in which one decides to do a large water change with water with totally different parameters which causes the Ph to rise too fast the fish can handle at a time, or the tank can't handle the chemistry in terms of not capable of dealing with the rise of toxic ammonia which process happens with a temperature and Ph rise.



> My fish breed at very low pH, and in fact, sometimes it's the only time that they will breed easily.



Yes, I am not saying anything against that. Some fish require this. But your fish are constantly in that same type of water with same chemistry, it's stable. If you don't inject CO2 or add ferts does your Ph or TDS change each day signifficantly? I presume not.



ceg4048 said:


> So people need to understand that they really ought not to unilaterally find ways of controlling pH without first understanding the WHY of a tanks pH.



I've never said anything about controlling the Ph. I am totally against Ph control with chemicals of any sort providing you can keep the stats stable normally via water changes and the minerals in the present water are enough to sustain healthy life.  But you ought to know whether there's a possibility for your Ph to drop in a day and kill your fish because of lack of buffers to keep the Ph stable.  In my water with a Kh of 8 this can hardly happen overnight. The Kh gets down slowly in the space of months if one doesn't replace the old water which gets acidic over time with water containing buffers.

If you are talking about keeping fish in pure RO water with 0 Kh, then I don't know anyone keeping fish in such water.
As far as I know people add minerals to the water before doing water changes. Some of these minerals form enough Kh to keep the tank's ph from fluctuating all over the place.

And then in normal tanks it's almost impossible to have water with 0 Kh because in high techs you may be dosing Ca and Mg occasionally and do regular water changes which I presume aren't 100% RO water so the buffering capacity is replenished often enough to prevent Ph fluctuations regardless of what the actual value is.

If you neglect the tank, don't do maintenance, overstock, overfeed, stop doing water changes, etc, then the water will one day become acidic enough in terms of lacking any buffering capacity and the Ph will swing all over the place. This happens way easier in a soft water tank because you start with naturally acidic water.


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## dw1305 (29 Apr 2014)

Hi all,





sciencefiction said:


> No matter the Ph they need it stable and not fluctuating with water changes or for lack of buffering.If the Ph is low because the water is soft but keeps stable at a certain value then as long as you keep soft water species you are ok. What I meant by it was really that a fluctuating Ph is dangerous, such as a sudden rise or sudden crash............. If you don't inject CO2 or add ferts does your Ph or TDS change each day signifficantly? I presume not.


You can get large diurnal changes in pH in low tech. situations as well. The problem is with pH as a measurement, it is only really applicable in buffered situations. As you get towards pure H2O it has less and less relevance. 

Soft water will always have swings in pH, mainly because small changes in water chemistry lead to large changes in the acid ("H+ donor": base("H+ acceptor") ratio, and that is what pH measures. 

This occurs in nature as well as in the aquarium, if you have a lot of plants then changes in the O2:CO2 ratio are enough to lead to swings from pH6 to pH8 during a single photo-cycle.  

cheers Darrel


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## sciencefiction (29 Apr 2014)

Thanks Darrel.
But in CO2 injected tanks and in nature the Ph swings are due to the different levels of O2:CO2 but that doesn't change the chemical composition of the water. Plus in nature the water is different, way less polluted so the swings of Ph do not cause an accidental toxicity of some other sort.
However in a fish tank that massively produces pollutants at any given time, it does have an effect on other factors such as ammonia toxicity or metal toxicity depending on ones water chemical composition, substrate type, level of stocking ,etc...The different types of bacteria will work in different ways under different Kh/Ph conditions having effect on the balance. A planted tank being way safer obviously because the extra processes going on.
It can have a detrimental effect the least on critters such as snails and shrimp molting and on other sensitive fish in general. A sudden drop in Ph may trigger spawning in some fish but disease in others.

Some people say my fish are doing great, so are my snails but they jumped/ran out of the tank....They do what they'd do in nature, try to move to a better place but unfortunately they find themselves locked in.

One thing I know from anecdotal experience is that when the Kh drops not being able to hold pretty stable Ph of some sort, my critters suffer. I am not sure whether it's because of the lack of useable carbonates/bicarbonates and the sudden extra H+ load instead of bonding with CO3 for example, starts trying to bond with my snail shells, possibly irritating the fish tissue too, or some other sort of chemical reaction happens, but they do not like it and there's a behavioural change the least.

Plus if the Ph is the ratio between H+ and OH- we still don't know whether you've got a ratio of 100:100 or 10 000:10 000. A drop in Ph increases the left side, decreasing the right side. So in some tanks a drop in Ph may not cause much difference because the original ratio is 1:1 and it will swing not many H+ to the left,  but in others people's tank it may have an impact because the ratio was 10 000:10 000 and it will swing thousands of H+ to the left causing way more acidic water no matter that in both tanks the Ph is the same? Or did I get this part wrong possibly?


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## sciencefiction (29 Apr 2014)

I also see why Ceg/Clive is so adamant about cleaning the tank/filters, plants and doing large water changes. In a high organic load tank in which the Ph fluctuates daily, any pollutant can turn into toxic solution either because the Ph went down(metal toxicity) or because it went up(ammonia toxicity), or because the organics start suddenly decomposing overnight when the Ph is back up and the bacteria picks up it's decomposing rate, and use up massive amounts of oxygen, etc........from which any inhabitant may suffer.  Especially if you have your tank out of whack due to algae issues or some other issues and the oxygen levels are lower to start with.

In a low tech tank the water will also become more acidic too and loaded with pollutants over time if not enough water changes are done where one day all your nice iron loaded clay substrate may become poisonous for example and one may be wrong blaming the low Ph but it's the consequences of the low Ph that may be detrimental. So I agree to a point that the Ph or the swings of Ph don't matter in a sterile environment but I don't think it's the case in a daily polluted fish tank unless you do daily large water changes daily and you are really adamant about it. But then laziness kicks in....or you just don't do enough maintenance required to remove the amount of pollutants in your particular tank. One maybe fine with 50% weekly, another tank may need 150% weekly to maintain the same level of water quality, a third maybe fine with 50% a month or less.


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## dw1305 (29 Apr 2014)

Hi all, 





sciencefiction said:


> But in CO2 injected tanks and in nature the Ph swings are due to the different levels of O2:CO2 but that doesn't change the chemical composition of the water.


 That's right when we add CO2 to water, the CO2~HCO3 equilibrium is changed and there is more H2CO3 in solution and the pH falls. Because we are adding CO2, even though we may have pearling and water super-saturated with O2, the potential pH rise due to the oxygen is masked. Have a look at this post <http://www.ukaps.org/forum/threads/ph-drop-high-alkalinity.30384/#post-319698>.





sciencefiction said:


> Plus in nature the water is different, way less polluted so the swings of Ph do not cause an accidental toxicity of some other sort.


 Not necessarily, that is why conductivity is a useful measurement. If you have fairly low conductivity (60 ppm TDS or 100 microS.) this is pretty clean water. In a planted tank with some DOC you can really ignore toxicity from heavy metals or NH3. 





sciencefiction said:


> Plus if the Ph is the ratio between H+ and OH- we still don't know whether you've got a ratio of 100:100 or 10 000:10 000. A drop in Ph increases the left side, decreasing the right side. So in some tanks a drop in Ph may not cause much difference because the original ratio is 1:1 and it will swing not many H+ to the left, but in others people's tank it may have an impact because the ratio was 10 000:10 000 and it will swing thousands of H+ to the left causing way more acidic water no matter that in both tanks the Ph is the same? Or did I get this part wrong possibly


 No that is the important bit, and why pH measurements are not very useful without some measure of dKH. Have a look at this thread: 
<http://www.ukaps.org/forum/threads/co2-injection-leading-to-large-decrease-in-ph.23327/#post-239720>

cheers Darrel


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## RichardJW (29 Apr 2014)

The bottom line in this discussion is find a healthy equilibrium and stick with it !! If you try to alter what what is nice and steady already you run the risk of see-sawing and as pointed out can end up with a 10,000:10,000 balance where 10:10 was fine .
Plenty of stable water changed has always worked for the majority - even RO is fraught with danger to the inexperienced as in its raw state it's 0 so potentially you can destabilise things as it's no buffering powers !


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## sciencefiction (29 Apr 2014)

dw1305 said:


> Not necessarily, that is why conductivity is a useful measurement. If you have fairly low conductivity (60 ppm TDS or 100 microS.) this is pretty clean water. In a planted tank with some DOC you can really ignore toxicity from heavy metals or NH3.


 
That's why I initially replied to Michael here saying the Ph itself is not an indicator of what type of water one has. He may have a high conductivity or low conductivity water regardless of his Ph of 6. His water may have buffers or no buffers, The H+ may be 10 or 10 000. So in his case a fast dropping Ph may have no effect or some effect, who knows...
I suppose RO mineralised water would be safer. I've never used RO so I have no idea how it works in practice.
The TDS/conductivity can be deceiving. I now have  a tank in which I haven't changed the water for about a year, maybe a few scoops the odd times when I top it up(a small tank) and the Gh, TDS and Kh have all decreased significantly. Is my water purerer because the TDS is showing way less? Or is it polluted because I haven't done any cleaning at all?


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## dw1305 (30 Apr 2014)

Hi all,





sciencefiction said:


> The TDS/conductivity can be deceiving. I now have a tank in which I haven't changed the water for about a year, maybe a few scoops the odd times when I top it up(a small tank) and the Gh, TDS and Kh have all decreased significantly.


 That is an interesting question, I can see how dGH and dKH can fall, but I can't see any mechanism for TDS to fall, unless it was really high to start with, and the water really alkaline. In that case the water could super-saturated with salts, which could then potentially precipitate out as less soluble compounds. 





sciencefiction said:


> Is my water purerer because the TDS is showing way less? Or is it polluted because I haven't done any cleaning at all?


 It will definitely have more DOC and other compounds and these would contribute to the TDS, if we actually measured TDS, rather than estimating it from the conductivity.  I'm a fairly fanatical water changer (small percentage change every day), and I only have very heavily planted tanks, so I never really have "old water" - <http://www.skepticalaquarist.com/bioacidification>.

cheers Darrel


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## sciencefiction (30 Apr 2014)

dw1305 said:


> That is an interesting question, I can see how dGH and dKH can fall, but I can't see any mechanism for TDS to fall, unless it was really high to start with, and the water really alkaline.


 The tap water is 300-ish TDS which I started with and alkaline(Gh 12, Kh 8, Ph 7.4) The TDS dropped over time. I thought at first my TDS meter was out of whack but it tests fine in the tanks I do 50% weekly water changes( they always have the same readings as the tap)
And yes, I presume the conductivity/TDS meter doesn't really measure the true TDS at all so this tank is probably loaded with organics despite the TDS readings lowering. As well as the TDS lowering from 300 to 200ppm over a year, the Gh has gone down from 12 to 7 and the Kh from 8 to 2. The Ph has remained constant 7.4 as it was to start with. Plants, shrimp and snails are doing great but they are hardy critters.  Another factor that may come in place is that I recently discovered the soil that is inside this tank has peat in it which I overlooked when I was setting up the tank.  Could that be the reason even for lowering TDS?



dw1305 said:


> I'm a fairly fanatical water changer (small percentage change every day), and I only have very heavily planted tanks, so I never really have "old water"


Yes, I totally agree, regular water changes are the way to go.  I am a water change person myself, always did 50% weekly on all tanks almost ritually but my life was a bit of a rollercoaster for the last 7-8 months(which is no excuse for the poor critters) so I left a couple of the 5 tanks that I thought can manage without much attention. They did to an extent but the chemistry went all directions as a result. Now the problem is I used to rely on the TDS meter to tell me about the tank. Now I think I can't as it maybe showing me the same reading but the tank water has gone way worse. Normally the TDS always rose over time if I skipped water changes. I never knew it can go down because of some chemical processes.


P.S. I feel I am hijacking this thread. I really apologize Michael. I hope the discussion may bring us some knowledge of how things work inside a tank.


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