pH question

[pisces22]

Hey everyone,
I live in the country and use well water. I have a water sofetner for some of the taps, so I have a choice between hard or soft water. The pH for both is quite high-8.4. I was worried about this at first but I was told by the pros here not to fiddle around with pH-just as long as it was stable its fine. My fish seem very healthy and active and are doing fine in their stable pH of 8.4. However, I was worried that such a high pH would be dangerous when it comes to ammonia-i know im over-simplifying the chemistry behind this-but is it true even the slightest bit of ammonia will be stressful to my fish with a pH of 8.4?? I'll have the complete water paremeters for tommorow (mon.sept27th). I cant test rite now-its late and i have school tommorow and my mom will yell at me lol!
Thanks

[Watcher74]

From what I understand, any ammonia in water above 7.0 is more harmful than it would be in a below 7.0 PH environment. As for the higher the PH goes the more toxic, I'm not sure at all.

But you should always consider possible ammonia presence as harmful and either do a fishless cycle or frequent large-scale water changes to minimize the damage to any fish.

[ChicoRaton]

The details of this may be wrong, but the general idea is right :rolleyes: Maybe happychem will come along and correct me if need be

anyhow, ammonia exists in two forms in water. NH3 and NH4+. The NH4+ is much more toxic to fish than the NH3. At ph below 7, most of the ammonia is in the form of NH3. As the ph rises, more and more of this is converted to NH4+. pH is a logarithmic scale, so at ph 8 you will have 10 times as much MH4+ relative to NH3 as at ph 7. Therefore, ammonia is highly toxic at ph 8.4, and it would be best to keep it as low as possible if there are fish in the tank.

However, if your tank is cycled, you shouldn't have to worry about ammonia.

[happychem]

At pH 8, you have 10x as much H+ as you would at pH 7. This will translate to more NH4+ as well, but it doesn't necessarily mean that all NH3 will be NH4+, although at pH 8.4, it may well be. I don't know the dissociation constant, so I can't calculate the equilibrium.

I remember getting in an argument with another member over a similar post. The poster had high pH and measurable, actually fairly high, NH3 and wanted to know if he/she should be trying to decrease pH. My point was that lowering pH is a little like treating the symptoms, not the disease. If you've got NH3, get on your water changes and get the NH3 levels down as low as you can. Stepping into the world of pH manipulation is asking for trouble. Your tank will set its pH based on your tap water chemistry and tank chemistry. Keep it stable and be thankful that you've got hard water that doesn't have pH swings like us soft water folks.

[RTR]

Ammonia toxicity is due to the comcentration of dissolved gas ammonia, NH3, not the ammonium ion, NH4+, which is in itself essentially non-toxic - so one discussion above got it backward. Happchem is correct that the proportions of ammonia to ammonium ion are dependent mainly upon pH, but also upon temperature, the ammonia rising in relation to ammonium ion as both pH and temperature increase, although the toxicity of the ammonia itself also changes - lower titers will be toxic at lower pH - which adds confusion. But as almost all hobby kits measure total ammonia nitrogen (TAN), it is not easy for most folks to read inonized versus non-ionized.

For more complete information, see:

http://www.thekrib.com/Chemistry/ammonia-toxicity.html

A broader table of ammonia/ammonium ion is available at:

http://edis.ifas.ufl.edu/FA031

HTH

[Cat]

I was going to ask about this myself, I live in a very hard water area to the point with my ph tests where its off the scale I actually get limescale around my pump!
I did tests for the first time on both my tanks at the weekend (one that has been running for ages and the other is a very new set up and both readings are the same. In my early days I found some particular species of fish I had absolutly no luck with at all they always died very quickly so I guessed they didn't like my hard water so I just avoided ever getting those fish.
Unfortunatly my test kit dosent test for ammonia but the NO2 and NO3 tests for both tanks were perfect. I have never liked the idea of tampering with my Ph. Do you think my water is okay?

[pisces22]

Okay! I got home from school and tested my aquarium's water Here are the results;

Ammonia: 0 ppm
NitrIte: 0 ppm
NitrAte: 0-20 ppm
Hardness: 120-250 ppm
Alkalinity (buffering?): 240
pH: 8.4

THe test kits are: Hagen NH3 and NH4 for ammonia and Mardel Test Strips for the others. I do a weekly water change (30%)and gravel vaccum so I am I right in thinking I am okay?
The fishies are healthy and active and colourful-I fed them frozen Brine Shrimp and they loved them lol

[OnyxFishies]

Okay! I got home from school and tested my aquarium's water Here are the results;

Ammonia: 0 ppm
NitrIte: 0 ppm
NitrAte: 0-20 ppm
Hardness: 120-250 ppm
Alkalinity (buffering?): 240
pH: 8.4

THe test kits are: Hagen NH3 and NH4 for ammonia and Mardel Test Strips for the others. I do a weekly water change (30%)and gravel vaccum so I am I right in thinking I am okay?
The fishies are healthy and active and colourful-I fed them frozen Brine Shrimp and they loved them lol

From your test results, your water looks great. Looks like your water change routine is working well. Test every so often to keep tabs on things, but basically just keep up the good work!

Alkalinity is *basically* a measure of your water's buffering capacity.. Not quite exactly, but it works out that way.