I am sorry I am relying on the science and the facts reported. Freshwater, I am insulted by your statementsAnd I have made a great effort to refrain from going after folks for having things so wrong, but you fired the first shot, your information advice and conclusions are not supported by either the science nor the facts here and I will show you and Nimbose why again.
1st am not assuming it is false positives, I am saying it flat out. And I can pretty much prove it.
"My 120 litre tropical tank has had an ammonia spike and it refuses to go lower than 0.50ppm; granted, it's better than it was and it was actually off the charts and killed five of my fish, but... I'm still not comfortable. Any ammonia is bad, after all."
"The tank has been running for a couple of months now, as I upgraded from a smaller 64 litre one."
These two statements tell us a few things- the tank had higher ammonia and had ammonia from some time, this ammonia came down but now is stuck at .50. So there has been some level of ammonia in that tank for some time- why is there no nitrite now why was there no nitrite issue ever? Why does nimbose state
"The only problem is the ammonia."
"I tried using Interpet Ammonia Remover, and while it got rid of the huge spike I had that caused the fish deaths, it hasn't done anything to help my problem now."
I know these products do not remove ammonia, they convert it to a form that doesn't show on tests but can be used by the bacteria. So even as fish died and then the ammonia readings appeared to vanish, it was there for the cycle to keep using but not to harm fish. So I know the cycle progressed to some degree. For some reason you would have us believe that a product which made ammonia readings so high they killed fish drop to zero is unable to handle .50 ppm of ammonia now? Please explain how this would be possible. Or did you not read this information?
Now since you are sure that repeated and steady .50 ppm reported is real and accurately measured, how do you explain that the level never rises from day to day and never drops either. Tell us, given the circumstances, how it is even remotely possible under any real world conditions to produce those results? It is impossible to engineer them, yet you would have us beleive it is possible for them to occur naturally in a tank. Horse hockey. You could not get those results on a bet or a dare. Nobody can. To quote Sherlock Holmes "
when you have eliminated the impossible, whatever remains, however improbable, must be the truth?" In this case, it is a false reading that remains.
If there is a daily reading of .5 ppm that is not getting turned into nitrite, are you saying the fish made this and then stopped making any more day in and day out? Why doesn't the ammonia ever rise if we know the fish keep making more every day and none is being converted. Where is it going? Why isn't it accumulating? And don't say to nitrite because that means you agree there are ammonia bacs at work. If there are ammonia bacs at work they always size up to the bio-load. How long does it take that many bacs to multiply to handle .5 ppm? FA so far you failed failed to address this or to refute it with any sort of facts.
What about the fact that Nimbose moved over some bacteria when she initially set up the new tank? Where does this information figure in your reaching your conclusions and giving your advice.
"The decorations, except the jellyfish, were all from my old aquarium. Hmn."
What about the fact that when one compares the remaining fish list to the fish that died list, the ammonia load in the tank was about cut in half. I cosidered this in what I said, did you FA?
With no nitrite readings you are again in a bit of a corner. Either there are no ammonia bacs, which is impossible here, so maybe there must be nitrite converting bacs dealing with it as it is produced? But that would mean the cycle is closer to done in terms of the fish load since the deaths than to being an uncycled tank.
Now FA I want you to defend your adivce: "First thing you should do is change as much of the water as possible, drain as much as you can leaving just enough so that the fish are swimming upright, about 90%."
Given a reading of .5 ppm, 0 nitrite and zero nitrate in a tank that turned out yo have a fairly low pH. Provide some scientific support for what you suggested. Show us evidence that .5 ppm total ammonia will do serious or lasting harm to the fish in that tank if it were there for several days or even two weeks. Especially since it is most likely 100% ammonium (NH4).
Acid waters ameliorate, whereas alkaline waters exacerbate ammonia toxicity. The threshold concentration of total ammonia ([NH3] + [NH4+]) resulting in unacceptable biological effects in freshwater, promulgated by the EPA (1998), is 3.48 mg N/liter at pH 6.5 and 0.25 mg N/liter at pH 9.0.
from
http/http/www.sciencedirect.com/science/article/pii/S1546509801200053
3.48 mg N/liter = 3.48 ppm Ammonia-Nitrogen. Since the test kit scales we use are measuring total ions, one has to multiply that 3.48 by 1.28 to convert it to that scale. So they are saying 4.45 ppm of ammonium at pH 6.5 is where harm starts. Isn't that just a wee bit higher than the .5 ppm you would have Nimbose panic about and change water by 90 %.
Nimbose reported:
I" did the normal PH test and it came out as 6.0. I thought that couldn't be right, and the instructions said a higher PH wouldn't react with the test so I did the High Range PH test. It almost looks like it's going to be 7.4 but the colour isn't quite dark enough."
and I replied
"As for the pH, your test results indicate you may have a pH crash. When you test with the high range kit and the result is 7.4, the lowest level, the next step is test using the low range kit. Conversely, if you test with the low range kit and the result is 7.6, you then test using the high kit."
The junk about degassing to know one's tap is correct, the problem is here it is t0tally irrelevant. The test was on a going tank. Either the tap is higher because it is devoid of Co2 when it comes out and needs to in gas and this supports there being a low pH in the tank. Why will letting the water sit raise the pH in the tap but putting it in a going tank with surface aggitation would not? Just the action of refilling the tank from a water change acts to balance the co2 in the water even as it goes in. Unless the tests are being done wrong or the kits are bad, this tank has a low pH. And even if th tap is hig pH and it is something in the tank that is lowering the pH, what difference does this make in what the tank pH is?
And then what about when Nimbose posted this:
"It's weird, though. I went downstairs to get a midnight snack and I thought I may as well check the tap PH (Normal and High Range) while I'm there and it definitely wasn't as soft as the tank. 7.0, minimum.
So something in the tank has lowered the PH, as I tested that again too and it still read as 6.0."
I accept this fact, why can't you FA? Especially since Nimbose has not done the tap test after doing an outgassing.
FA, find us some scientific support or research that .50 or even 1.0 ppm of total ammonia will do irreversible harm or to or kill the fish in this thread and at the parameters involved of they are in it for a week or two.
One last comment, Nitrate is 0. Likely because of the combination of two things, the water changes and the two big sword plants. Do not worry about nitrate. Most of the kits are flakey and you will get different results depending in how you shake the bottles. Test the same water water with 3 different kits shaking as desired and you wont get 3 close to identical readings. I will never rely on the presence or absence of nitrates in a tank (especially planted) to decide it it is cycled or not.
You totally ignored all of the explanations I provided and provide them with your inaccurate information without any rationale or explanation to support your advice.
So I will make things really simple. Nimbose, I have always advised people to pick one voice and listen to it. It minimizes the confusion. If you think what I have said is not logical, is not factually sound, is not supported by science; if you believe I have no idea what I am talking about, then by all means listen to AF or to somebody else. Trust me, I will not be offended nor will it influence me in any way should you want my help with something down the road.
If you wish my continued input I am more than happy to help you. I would prefer to do it in PM. In that case. When things either work out well or else fall apart as a result of your having followed my advice, post about it here. You can post what I suggest to you and what happened as a result, I won't object. I will refrain from posting here any more to avoid a contrary voice.