pH - general thoughts

Sarcastic

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This is going to be a hodge podge of thoughts about the behaviour of pH in a Freshwater tank. There's no crisis, all my fish seem healthy and happy, I'm just trying to get a broader understanding of pH.

As I understand it, "muck" in the water will make more the water more acidic, and thus lower the pH. So, why isn't there an inverse relationship between pH and nitrates (nitrates rise and pH declines)?

For a community tank, what do you consider an extreme pH shift? (Look at my next two questions for more on this thought.)

I find that over a period of about 5 weeks the pH gradually declines from just under 7.0 to around 6.4 or 6.5. I make 20% water changes weekly with R/O water treated with Electro-Right and pH adjuster. Every other month I add 1 Gal of "strong tonic" - a powdered pH buffer in a ratio against the total volume of my tank, with Electro-Right and a couple of teaspoons of salt. The pH bounces up near to 7.0 overnight.

I notice that as the carbon filter insert in my filter (an Aquaclear 300 on a 29-Gal long aquarium) ages, that the pH declines. I use this as a guide as to when the carbon filter is spent - when the pH drops to 6.5 or so I change it out. Then the pH comes back up to about 6.9 - which is the average pH my tank maintains. Is this the common experience?
 

sgould

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I've never even tested the pH of my tanks. Everyone I have talked with has indicated that tank raised fish will adapt just fine to whatever your pH is, and have not had any problems with fish, so I have not yet seen a benefit to monitoring it that closely.

I guess that probably wasn't too helpfull... :-[
 

tan.b

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sgould said:
I've never even tested the pH of my tanks.  Everyone I have talked with has indicated that tank raised fish will adapt just fine to whatever your pH is, and have not had any problems with fish, so I have not yet seen a benefit to monitoring it that closely.

I guess that probably wasn't too helpfull...   :-[ 
that's about all I can say too! my pH is always stable at 7.2, although my tetra tank shifted itself this week to 6.4 for the first time. suspect a shell in there may have done that although i'd expect the mineral content to raise the pH rather than lower it?! who knows?
but so long as pH adjusts slowly fish will adapt. its the constant changes in pH that upset them. sorry I can't offer any inspiration to your thoughts!
 

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HI there, I have a little experience with your situation. An extreme pH shift would be anything more than .2 either up or down. Example - from 7.0 to 6.7 or lower. You are doing great with water changes it sounds like but I am wondering why you are using reverse osmosis water which takes all the minerals and buffers out and makes the water soft/acidic and then adding buffers and things to raise the pH? Fish do best in stable pH vs. specific pH and the species you have in your tank are all fairly hardy fish that can take pH up to 7.5 even if not a little more. The problem with doctoring your water the way you are is the effects tend to be temporary and it causes a pH rollercoaster that over time, will stress your fish out and lead to disease susceptibility or even death. I did this a few years ago. I tried to get 7.0 water and I had 7.6 - 7.8 coming out of my tap. I learned the hard way (killing my tank of Tiger Barbs) that it would have been better to let them adjust to what my pH was naturally than trying to attain a specific pH that they might have preferred. My water's pH didn't stay stable as yours isn't and I spent a ton of time and money trying to keep them healthy and happy. They got sick, they nipped fins more than they normally do and they all got fin rot and basically it was a mess. I am sure your fish are fine now but as time goes on, it may stress them out and they may not live as long etc. As to your question on the pH shift and nitrate levels. Your pH can drop if your nitrates are really, really high? How much are your readings? Under 40 is desireable or they too can get a little toxic. As far as your carbon is concerned, activated carbon only helps out for a very short period of time. Sometimes only days does it work before it has adsorbed all it can from your tank water. The reason it seems to work so well for most people is because it has thousands of surfaces that can house the nitrifying bacteria for your biological filter that is the most important filter in your aquarium. If you want it to work more for you, you may need to change it more often or put two filters on and switch out changing the media every other time between the filters. The carbon doesn't really have a whole lot to do with your pH though. It is most likely the chemicals and buffers you are putting in. Is there a reason you can;t use tap water? Do you have a well or city water? I could probably help you out more if I knew what your tap was producing and why you were using the R/O water instead. Let me know.
 

kalika

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I just remembered! What do you use to test your water with? If you are using the API master test kit, there is a sticky in here somewhere, someone with the sign on "Terry" found out that you have to really shake the 2nd bottle of the nitrate test really well because there is an ingredient that will solidify in the bottle and if it isn't mixed in, it can give you falsely low readings. The point is, if you are using that test kit, and if that has been happening to you, you should look up that post and shake your bottle because maybe you have higher nitrates than you think contributing to your pH swings. I know this all sounds like a lot but I know it isn't only me who has had these experiences and If I had known back then that there was a forum I could join to get these kind of answers that are better than what anyone in an LFS has ever told me, I would have saved myself a lot of heartache and frustration and dead fish. Again everyone is here to help and if you have more questions or concerns, never be afraid to ask.
 

COBettaCouple

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At first, we used stuff like pH Down & those fizzy tablets, etc. trying to get to the magic number of 7.0 but they really seemed to be a waste of money and then we started reading how fish do adjust to their surroundings and it was better to let them adjust & be happy at 6.4 or 7.6 than stress them with trying to force the pH to 7.0

Our pH stays pretty stable. We used treated tap water and the API master test kit also.. and AmQuel+ if we need to.
 
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Thanks for the input.

kalika said:
An extreme pH shift would be anything more than .2 either up or down.  Example - from 7.0 to 6.7 or lower.
Thanks for that. Its useful to have a frame of reference. The range on my tank is between 6.5 and 6.9 over time. The shift happens gradually a period of a week or two. I was worrying that was an extreme shift - and that worry has been founded.

kalika said:
You are doing great with water changes it sounds like but I am wondering why you are using reverse osmosis water which takes all the minerals and buffers out and makes the water soft/acidic and then adding buffers and things to raise the pH?  Fish do best in stable pH vs. specific pH and the species you have in your tank are all fairly hardy fish that can take pH up to 7.5 even if not a little more.  The problem with doctoring your water the way you are is the effects tend to be temporary and it causes a pH rollercoaster that over time, will stress your fish out and lead to disease susceptibility or even death.........Is there a reason you can't use tap water?  Do you have a well or city water?  I could probably help you out more if I knew what your tap was producing and why you were using the R/O water instead.  Let me know.
This worries me, too. I live in Brooklyn, NY and have city water. I came to this situation because my tap water is extremely soft (pH of 6.0,  1°> dGh, 1°> dKh) and has a high level of phosphates and sulphur. I was using distilled water for water changes up until recently and this was equally soft, just without the other minerals that my tap water has. About 3 weeks ago I bought an Aquarium Pharmaceuticals Tap Water Filter for Aquariums and now use that to filter my tap water. Any advice on this topic would be appreciated.

kalika said:
They got sick, they nipped fins more than they normally do and they all got fin rot and basically it was a mess. 
Interesting observation. My fish are seemingly healthy - clean and full eyes, fins and scales, happy consistent behaviour, etc., yet I do notice some aggressiveness, though, where (according to the literature) there shouldn't be. One of my Silver Dollars often harasses the other. And I have one Swordtail who has murdered everyone in her species I tried to introduce to the tank (but doesn't go after any other fish).

kalika said:
As to your question on the pH shift and nitrate levels.  Your pH can drop if your nitrates are really, really high?  How much are your readings?  Under 40 is desirable or they too can get a little toxic.   
This was more of a general question - not really a problem I am having. The levels of Nitrate in my tank are consistently around or below 20ppm. There have been two instances where I was out of town for over a week and the Nitrate level rose to about 35ppm. In both those instances the pH remained at 6.8. It seems, based on my limited understanding, that the pH should drop as Nitrate levels rise - but this wasn't borne out by these examples. Maybe its only in the extreme range that Nitrate impacts acidity? Or maybe I am mistaken in hypothesizing this correlation?

kalika said:
As far as your carbon is concerned, activated carbon only helps out for a very short period of time....... If you want it to work more for you, you may need to change it more often or put two filters on and switch out changing the media every other time between the filters.  The carbon doesn't really have a whole lot to do with your pH though.......
I change the carbon filter insert approximately every 3 weeks. The trigger, besides the timetable, that I use to know when its time to change is the pH. The pH gradually declines towards 6.5. When I change the carbon insert, it rebounds within 1 week to 6.9.

kalika said:
If you are using the API master test kit, there is a sticky in here somewhere...
I do use the API master test kit, and I read that sticky some time ago. I shake the #2 bottle for Nitrates thoroughly, shake the test tube to make sure it mixes well, and give it a full 5+ minutes to take color.
 

tan.b

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not wanting to sound picky or awkward, but with the nitrate testing solution it needs to be exactly 5 mins. much longer and the colour will go even darker still, thus resulting in a falsely high reading. but as you both mentioned, leave it not long enough or not shaken enough and you get a false low reading :. it seems in particular with the nitrate test you need to be quite precise with it all to get a precise reading!! tan
 

COBettaCouple

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tan.b said:
not wanting to sound picky or awkward, but with the nitrate testing solution it needs to be exactly 5 mins. much longer and the colour will go even darker still, thus resulting in a falsely high reading. but as you both mentioned, leave it not long enough or not shaken enough and you get a false low reading :. it seems in particular with the nitrate test you need to be quite precise with it all to get a precise reading!! tan
hmm.. I try to do the tests as accurate as I can, but sounds like I need to be more exact on the timing to not let it sit too long. Thanks for the tip.
 

kalika

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Wow!  You obviously love your fish.  I was going to suggest that tap water filter you have.  That kind of stinks that you have sulfur in your tap water.  If your nitrates are that low then they aren't hurting your pH at all.  The reason they do if they get high is simply the way the bio-filter works.  When waste is produced and the bacteria turn it into nitrite and then into nitrate it can at times compound, what I mean is if you have really high nitrates it means that you have also then had a lot of waste that was turned into through that biological cycle.  It is good that the bacteria are alive and well and doing that but it would also mean more water changes or less fish or less feeding etc to keep them down, your levels are just fine though.  You were right on hypothesizing that there was a correlation between the two.  As far as the way your swordtail is behaving there could be several reasons for that.  How many other swordtails have you introduced to her?  Do add at least two or more at a time?  Swordtails are generally very peaceful and like to loosely school.  Of course that is a generalization and sometimes you find a fish here and there that are more aggressive or shy than others of their species.  They all do have very different personalities.  If you add more that one friend, that may help.  She may also be a little extra territorial so when adding new fish it could help if you re-arrange the decor in the tank so it upsets the ownership of the different areas of the tank by rouge fish like yours.  Another thing would be what are you feeding them?  You sound like you really have it together but I learned the hard way as well that a varied diet is best.  Not just because it gives the fish more nutrients etc. (even different flake foods have different ingredients between the brands) but also, especially with omnivorous fish, it is important that they get some kind of meat in their diet.  I don't mean table food but some frozen brine shrimp or freeze dried blood worms can help if given on a regular basis at least a few times a week.  I once had a kissing gouramI that developed a taste for the other's slime coating an proceded to eat it off of them and killed two of my favorites.  It turned out that he just needed a little brine shrimp added more often to his diet and he quit doing that.  The other reason for the aggression could very well be your pH swings.  It is a huge swing but it is a little much.  At least it isn't swinging that much overnight all the time.  That does help a little.  As far as you now filtered tap water which is still extremely soft, the only other thing I canthink of besides constantly monitoring your water and possibly doing more frequent water changes to keep the pH more stable (2 - 3 times a week) I would think about getting fish that just naturally love soft water.  I happen to really like tetras of all species and these fish love soft water.  I have 7.6 coming out of my tap so my water is king of hard.  I can only keep a few species of tetras so I had to learn to love that fish that will be either hardy enough to adapt to my water and be OK and then mostly keep fish that like harder water.  So Zebra Danios are great, just not that colorful.  Anyway, I am also lucky there is one LFS near me that has the same city water I have and they don't treat it with pH adjusters so any fish I buy there is already used to my pH, just not the same chemicals I treat the water with.  If you can find a store near you that keeps their fish in the same water you have (of course probably filtered to at least take care of the phosphorus and sulfur) and the fish look healthy, you can bet they would be good fish to buy for your tank.  The Amquel mentioned in another post by the FLBettaCouple does work and helps to take care of ammonia etc in the water but the only problem with it is it can compromise your biological filter and doesn't eliminate the reason for needing it.  Even if ammonia is neutralized, it is still being produced.  It is usually better to eliminate causes vs. treating symptoms.  I am not saying it is bad, just that you need to be careful of what you put in your water and why.  I know this is getting lengthy so I will try to cut it short.  The reason for this too is that everything in your water can cause what is called osmotic stress on your fish.  So putting things in to treat ammonia or nitrites or algae etc vs. using preventative measure put that stress on the fish because it is more stuff in the water that is coming into contact with their gills and blood stream.  The cleaner and simpler you can get with the water you keep them in the easier it will be for you and healthier for your fish.  I hope I am not sounding harsh here at all, I have just learned theses lessons the hard way and did give up the aquarium hobby for quite a while before trying it again because of similar problems.  I would hate to see you do that.  You do seem to have everything together and the situations you are describing are exactly the kind of things that a lot of stores out there don't know a whole lot about, especially petco or petsmart.  If the store doesn't specialize in fish, you have to be careful of their advice.  Even if they do like the one near me that keeps their fish in the city water like me, they still haven't been consistently doing their research on things like how often to do a partial water change etc.  I get good fish there and good products but a lot of time not so great advice.  I really hope this helps you out!  Again, if you have more questions, ask!  You can even email me personally if you want, just look it up under my profile.  It is my work email so I am here during the day and do have a day off a week so if I don't get back to you right away, that is why.  At least until I get my high speed set up at home in a few weeks.  Good luck, let me know how things are going for you.
 

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