Is my ph a problem? - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 10 Old 01-09-2013, 08:20 AM Thread Starter
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Is my ph a problem?

Due to some sort of strangeness in my local water, the ph of the water in my fish tank tends quite acidic. By quite acidic, I mean it reliably reads 6.0. I've confirmed with the people at the lfs that they have the same problem with the local water. On their advice, I added a ph stabilizing chemical which brought the water to a perfect 7.0. That was only 3 days ago, and it's already returned to 6.0. Is this ph low enough that I should be concerned? If so, what can I do to raise it on a more permanent basis? It's not practical for me to be adding chemicals everyday.
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post #2 of 10 Old 01-09-2013, 08:26 AM
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Rather than trying to do this have you considered just having the fish suit your water? Trying to do it the other way round as you have said is just not practical, nor will it ever be good to keep having to add so many chemicals in.

I'd say just have fish that thrive in your water conditions
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post #3 of 10 Old 01-09-2013, 08:40 AM
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One of the largest misconceptions about fish keeping is the desire to have a pH of 7. A pH of 7 is actually extremely unnatural.

There are two catagories of freshwater fish. Soft water, and hard water. With few exceptions, soft water fish excel at pH's less than 7 (in other words acidic water) along with a low GH (General Hardness, in other words soft water).

What kind of fish do you have? You may actually have ideal water for them. In fact, there are a lot of fish who do very well (even thrive) in a pH less than 6. Each species has its own requirement though.

The other kind of fish are hardwater fish, and they prefer basic water (pH above 7) and a high GH. These are mostly livebearers (like platy, molly, guppy, etc) and African lake cichlids.

Using chemicals is never a good idea. It does exactly what you saw. It temporarily changes the pH, and then things crash. pH swings is extremely harmful to the fish's health and there is never a case where I would recommend a chemical to adjust pH. If you wish to keep hard water fish, the better solution is to use a calcareous substrate which will not only raise the GH, but the buffering capacity as well (KH, Carbonate Hardness) which results in a corresponding rise in pH.

GH, KH, and pH are all related.
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post #4 of 10 Old 01-09-2013, 08:47 AM Thread Starter
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Currently I have glowlight tetras. One of them died this morning, which is why I was worried, but apart from the ph, all of the other water readings are fine. I just got these fish Sunday, so it's possibly he was injured in transport. All the others seem fine.
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post #5 of 10 Old 01-09-2013, 09:00 AM
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Those are soft water fish, so I wouldn't worry about the pH at all, leave it be. You may wish to find out your GH and KH of your tap water. Your water utility can tell you (sometimes on their website in the water quality report) and give you a very accurate number, otherwise you can get it tested at a LFS usually for free but all you'll get is a ballpark number (and do get the number, don't settle for words like 'hard' or 'soft'). No need buying your own test kit, unless you plan on adjusting it you would only use it once.

For the fish dying, there could be three main reasons or a combination.

1) Is this a new tank? Was it cycled (and if so how)? If it's new, and not cycled, that's a common cause of death.

2) Rapid pH swings from the chemicals

3) Sick/diseased from store (all new fish should be quarantined for a month before adding to a tank but if they're your only fish by definition their in quarantine ;) )

"all my other readings were fine" can you give the numbers? "Fine" means different things to different people =)
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post #6 of 10 Old 01-09-2013, 09:10 AM Thread Starter
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According to the city water quality report, the hardness is 25 ppm. I doesn't say anything about KH. I've successfully kept both tetras and platies before without doing anything to the water, so it must not be totally horrible.

These are the only fish I have right now, so there is no risk of infection. However, none of them, including the one that died have any signs to indicate disease. I wasn't entirely happy with how the woman at the store handled the fish when netting them, so it is possible that one was injured.

My measurements are:
ammonia- 0ppm
nitrites- 0ppm
nitrates- 10ppm
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post #7 of 10 Old 01-09-2013, 09:37 AM
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I would say the most likely cause is actually the rapid pH change. 1 full point on the pH scale is really a 10 time difference, it's a logarithmic scale. For example 6 to 7 is a 10 time change. 6.0 to 7.1 is a 20 time change, and 6 to 8 is a 100 times change. so you can see how quickly that grows into a massive and dramatic shift.

25 ppm is really soft water, perfect for the tetras, not perfect for the platy's. The effects of this is a gradual thing, something over the course of months to years rather than anything sudden. It's the difference for example of a fish living 3-4 years versus the 5 that is normal.

You are in a situation many fishkeepers dream of, and I have the same benefit. Soft water opens the doors to all kinds of possibilities. It's very easy to make soft water hard, but difficult and expensive to make hard water soft.

My advice is to take a look at the fish profiles here on the site and use the information there to plan out how you'd like your tank to be stocked in the end. The Glowlight Tetra is in there (you can also click the blue shaded name right here in this post) along with Platy. Towards the bottom of each page you can see the water parameters each fish needs. Most profiles here use the unit dGH which stands for Degrees of General Hardness. The conversion is 17.848 ppm = 1 dGH so your 25 ppm water is 1.4 dGH and is very soft water.

You could even keep Discus with just using your tap water if you had a large enough tank, that's enough to make lots of people jealous ;)
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post #8 of 10 Old 01-09-2013, 10:19 AM Thread Starter
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Thanks for your advice Geomancer. I have been leaning towards just keeping soft water fish because it seems like there are many and messing around with chemicals makes me nervous. If I do this, how should I deal with introducing new fish into the tank? I know that the lfs treats their tanks to close to neutral. I do try to acclimate my new fish slowly, but I worry that it may not be enough if the ph is way different.
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post #9 of 10 Old 01-09-2013, 11:26 AM
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There are two ways to do it. With particularly sensitive fish the best method is called drip acclimation. Basically you set up a piece of airline tubing that slowly drips water and over the course of an hour or two acclimates the fish to the new conditions.

For most fish though, you can simply just float their bag to equalize temperature. While you are doing that, remove half the water from the bag and discard. Every 5-10 minutes or so, take 1/4 to 1/2 cup or so of water from your tank and put it into the bag. Keep doing that until the bag is full, then repeat one more time, takes about a half hour. The exact amount of water you scoop out and the exact amount of time isn't really critical, you are just aiming for a more gradual change over time versus a sudden change.

When finished, just poor the bag out into the sink through a fish net. The fish will get caught in the net and you can then just plop them into your tank. That's usually easier than trying to net them in the bag itself.

Doing all of this with the tank lights off helps with stress, leave the lights off for the rest of the day.

An added safety measure is to quarantine all new fish for a month before adding them to a main tank. This requires a second tank that's cycled and/or fully planted. You would still acclimate them to the quarantine tank, but you likely wouldn't have to acclimate them from the QT to main tank unless they are a sensitive fish (or if for some reason your pH and temp is fairly different between tanks).
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post #10 of 10 Old 01-09-2013, 12:23 PM
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I hardly need to post, as Geo has covered this issue very well. So I will just point you to an article I wrote on hardness and pH that may help to explain the background of what's going on:

The above link will take you to it direct, but it is in the Freshwater Article section, and there are some other articles on various aspects of freshwater aquaria that may be helpful too.

If you read that article you will understand why the pH will continue to lower naturally, so don't fight it. You might want to raise the GH a bit, if you have or would like to have live plants. We can discuss this if you do. Live plants are very useful with soft water fish.


Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
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