Ph Keeps Changing? Also Ammonia Always .25

[Fluval-1200]

Ok Ive had my tank running for about 6 months now and ive ran into a problem.
Im using an api liquid test kit.
My tank is a 323litre tank with a fluval fx5 filter, ive got some java fern and moss, a large fake rock and large piece of bogwood.
My ph levels constantly change.
Tapwater ph is about 8 straight out of tap.
Wednesday my ph was 7.6
Thursday my ph as 6
Today my ph is 7.4
Im not running co2 and last night I done a 20% water change.
 
Also I tested for ammonia before I changed the water, it was .25
Then I tested it again this morning, its still .25
 
Have a got a duff test kit or has my water got a problem?
 
 

 

[misterpro]

I'd guess that your result of 6 thursday was wrong (unless you messed with PH changing chemicals recently). Did you lose fish? A large PH change down and back up would've killed some fish.

*edit* Read over the 20% waterchange... What's the gh / kh of your water? (If it's extremely low your ph can crash. And the waterchange might have added some buffering, so it flew back up)

 

[snazy]

Tap water Ph can be different than once it settles because of different additives used by the water company which will outgass.  Fill an open glass, leave it at least 24hrs, then test. That should be your regular Ph. But you don't want your tank's water Ph to change at all.
 
The Ph is normally being buffered by what's called KH(carbonate hardness). If the Kh is very low then your water doesn't have buffering capacity and the Ph will fluctuate all over the place. That's because in a fish tank the Kh gets somewhat "consumed" due to many natural chemical processes that go on inside. Using a bit of crushed coral in the filter(starting from a small amount) can help maintain the Kh.
 
When the Ph is below 6.5 the beneficial bacteria gets inhibited and at ph of 6 and below it stops functioning, hence why you may get an ammonia reading. But the lower the Ph and temperature, the less toxic the ammonia at these levels. However, doing a water change that shifts the Ph back up all of a sudden, will make the ammonia more toxic and any Ph change is no good anyway to the fish because they can go into osmotic shock and die.

 

[Fluval-1200]

I'd guess that your result of 6 thursday was wrong (unless you messed with PH changing chemicals recently). Did you lose fish? A large PH change down and back up would've killed some fish.

*edit* Read over the 20% waterchange... What's the gh / kh of your water? (If it's extremely low your ph can crash. And the waterchange might have added some buffering, so it flew back up)

Not lost any fish, not sure what the gh kh is as I don't have kit for that.

Tap water Ph can be different than once it settles because of different additives used by the water company which will outgass.  Fill an open glass, leave it at least 24hrs, then test. That should be your regular Ph. But you don't want your tank's water Ph to change at all.
 
The Ph is normally being buffered by what's called KH(carbonate hardness). If the Kh is very low then your water doesn't have buffering capacity and the Ph will fluctuate all over the place. That's because in a fish tank the Kh gets somewhat "consumed" due to many natural chemical processes that go on inside. Using a bit of crushed coral in the filter(starting from a small amount) can help maintain the Kh.
 
When the Ph is below 6.5 the beneficial bacteria gets inhibited and at ph of 6 and below it stops functioning, hence why you may get an ammonia reading. But the lower the Ph and temperature, the less toxic the ammonia at these levels. However, doing a water change that shifts the Ph back up all of a sudden, will make the ammonia more toxic and any Ph change is no good anyway to the fish because they can go into osmotic shock and die.

Il give the standing water ph a try.
Will the plants be effecting the kh? I know they use carbon (maybe there taking the carbon away?)
Il test my ph again in a sec.

 

[snazy]

I'd guess that your result of 6 thursday was wrong (unless you messed with PH changing chemicals recently). Did you lose fish? A large PH change down and back up would've killed some fish.

*edit* Read over the 20% waterchange... What's the gh / kh of your water? (If it's extremely low your ph can crash. And the waterchange might have added some buffering, so it flew back up)

Not lost any fish, not sure what the gh kh is as I don't have kit for that.

 
If you really have a fluctuating Ph, grab at least a liquid Kh test. They are fairly cheap.
The fish may survive a slow change in Ph, some are more sensitive to this, some less but a rapid change is dangerous.

 

[Blondielovesfish]

Test your tap water for ammonia.

 

[TwoTankAmin]

I doubt the 6 pH reading is reliable. I manipulate the pH in several tanks. Mostly making it 1.0 to 1.5 lower than my tap. It is not easy to move the pH by that amount rapidly without doing some things to cause it.
 
While I do not wish to make a huge issue of it, I have personally changed the pH of tanks with fish in them by over 1.0 inside of 5 minutes with no ill effects. I have watched others do this as well. In all cases the pH was being monitored digitally. However, this doesn't mean any and all fish can handle this. What it does mean is it is incorrect to make the blanket statement that fish are unable to handle a large rapid change. Some can and some can't. The simple rule is if you are not certain the fish you have in a tank can handle that sort of change, do not subject them to it. But please do not imply that no fish can handle such changes because it simply is not true.
 
Water companies do indeed manipulate pH to make treatments work better. However, what usually is at work relative to tap pH differing from tank pH is there is either an excess or a lack of dissolved CO2 in the tap water. Too much causes the pH to be artificially low and too little makes it appear artificially higher. So to test it you can fill a small container from the tap and put in an air stone and bubble the water for a couple of hours. This allows any excess co2 to out gas or for water deficient in co2 to have it in gas. Using the air stone works faster as it breaks the surface tension of still water which facilitates gas exchange between the air and the water. Also, find out what the KH out of the tap is as mentioned above.
 
More often then not, a .25 ppm ammonia reading in an established tank is not real. Something has to cause it if it is real. And then the next thing that would happen is there would be a bit of nitrite showing up as well because of the "excess ammonia." There are many other things that can cause one to get a .25 when its not there. As long as you don't see nitrite and your fish appear to be behaving normally, that reading is probably not real. What might legitimately cause it are the death of a fish whose body rots some before its discovered or an excess of dead organic matter from things that die- this includes algae, plants, the blue/green algae (this is actually a bacteria). Basically, ammonia doesn't suddenly appear, something has to cause it.
 
Your plants should not be using up the carbonates that contribute to KH, plants use CO2. In order to have enough co2 in a tank to alter the pH and KH in any noticeable way, one must be adding co2 gas.

 

[Fluval-1200]

Ok I finally received my gh and kh test kit.
Kh is 35.8ppm
Gh is 107.4ppm
 
I had bought a large fake rock for my tank, I rearranged my tank other day and I pulled the fake rock out....it was absolutely stinking of death!!!, it was full of decaying plants and fish muck. 
20% water change a day for 2 days and now ammonia is 0
 
The test kit says the gh-kh is fine but what are your thoughts?

 

[snazy]

Ok I finally received my gh and kh test kit.
Kh is 35.8ppm
Gh is 107.4ppm
 
I had bought a large fake rock for my tank, I rearranged my tank other day and I pulled the fake rock out....it was absolutely stinking of death!!!, it was full of decaying plants and fish muck. 
20% water change a day for 2 days and now ammonia is 0
 
The test kit says the gh-kh is fine but what are your thoughts?

 
You've got very soft water. Your Kh in particular is very low and that's causing the fluctutations in Ph as the Kh naturally gets lower in a fish tank, and you normally would need about 70ppm to keep the stats stable at all time.
 
You can try crushed coral in the filter, but start from a very little amount and add little by little until you Kh is about 70-72ppm or slightly less. That will also affect your Gh to an extent so it needs to be done slowly as to not stress the fish. Once you achieve the desired value, just keep that amount of crushed coral in a bag in the filter and it will slowly work it's charm over time.
 
The good part is that you can keep some soft water species of fish that will appreciate this type of water.

 

[misterpro]

Gh is soft but fine.  Kh however is too low.
 
In tanks with a low KH value, say under 2-3d (35.7-53.6ppm), the respiration of the plants or animals at night (CO2 production) can cause large pH shifts which harm and eventually kill aquatic animals. This is called pH shock. It is due to lack of water buffering.
 
That's a quote from the aquarium wiki
 
It has instructions on what to add to raise your Kh and a calculator to measure how many teaspoons.  They recommend it should never be under 4°d (71.4ppm).

 

[Fluval-1200]

Thanks for the info, I should be running a co2 system in the next couple of days. Will that make a difference at all?
Should I tank the plants out? I have a plant grow tank running atm with a yeast co2 system

 

[snazy]

Will that make a difference at all?
 

 
Don't run the CO2 before you get the Kh sorted. Sorting the Kh is even more important when injecting CO2 as your Ph will be all over the place, changing too fast,  and you risk killing the fish and filter bacteria. The recommended for any planted tank is the same, 70-ish ppm Kh the minimum.

 

[Fluval-1200]

Luckily my diffuser hasn't arrived then lol.
I will add some crushed coral to my filter.
Should I take plants out?

 

[snazy]

No, why would you take the plants out?
Sort the Kh, give it a bit of time to see if it stays stable, then connect the CO2 system and enjoy your planted tank growing

 

[Fluval-1200]

I thought taking the plants out would stop the tank ph changing so rapidly at night lol.
Thanks for the info il get some crushed coral in my filter asap.