Water Quality Problems, Help!

[Ribcracker]

I am relatively new to the hobby, but loving it.

I have a 125L tank which seemed to be going ok but I had a few losses, the ammonia, nitrite, nitrate kept bobbing up and down, despite a 25% water change every 2 days.
Then the tank got a dose of Whitespot, another couple of deaths.
Also, the filter seemed to be getting clogged with waste mid-week, so assuming the filter wasn't performing to the optimum I replaced it with a Fluval 405, my thinking being you can't have too much filtration.
I added the sponges from the old filter as well as a pouch of ammonia remover and a nitrate absober and added a good dose of StressZyme to kick start the filter.
I dosed for Whitespot with Malachite Green and the whitespot has cleared up nicely. The affected Bala shark has retuned to his playful self.

So, tonight I tested the water, it was up on ammonia and nitrate, despite the pouches of ammo remover etc.
I did a 50% water change to clear the water and medication and added a carbon to clear the meds.
I left it a couple of hours then tested the water again; the results were ammonia 0.25 and nitrate 0.5.
I suspect the medication has killed the bacteria in the filter and it needs to be cycled as it doesn't seem to be doing it's job properly.
As I have fish in the tank and nowhere to re-house them, how do I get the filter up and functional again?

 

[OldMan47]

Welcome to the forum RibCracker. What I would do in your situation is stop using the ammonia and nitrate remover completely. The filter will take care of ammonia very nicely on its own and the way to remove nitrates safely is to do an occasional water change. You may be correct that you are at the beginning of a fish-in cycle. That is not a disaster and can be managed quite well if you are willing to do the work. Your chemistry says that it is time to do a 50% water change. The idea of a fish-in cycle is quite simple. You do large enough water changes often enough that the water never has more than 0.25 ppm of ammonia or nitrites in it. All it takes is water testing and the willingness to stay on top of the water changes. As the next week or two go by, it may take more or less water changes to keep up because the bacteria population in the filter will change and mature over time. In a few weeks, you should not need to do any water changes to keep ammonia and nitrites under control. At that time you start judging how large and how often you need to do water changes to keep the nitrates from building more than 20 ppm above your tap water nitrate reading. That is usually only a small weekly water change.

The problem with ammonia and nitrate absorbing materials is that they become exhausted. When they become exhausted, you have typically kept the filter bacteria from developing properly and suddenly the fish are faced with more ammonia than they can survive. In the case of nitrate absorbers, you have lulled yourself into the false assumption that you don't need to do big water changes, then suddenly you do but you are not in any kind of routine that will maintain the nitrates and don't know how big a water change to do. It is the reason that I suggested you stop using them, they are a poor substitute for proper aquarium care.

There is a link to fish-in cycling in my signature area that will give better details on how to go about doing a fish-in cycle. I have just touched the surface here.

 

[Ribcracker]

Thanks OldMan for the rapid response.
I will remove the Ammo remover and Nitrate absorber.
In the Fluval 405 I have 3x BioMax, 2x PreFilter, 1x Carbon, 1x Fine Foam I am hoping it will seed soon as I have a 350L custom built tank coming in 2-3 weeks and want to swap all my gear straight over leaving the old tank for my daughter to keep coldwater in.

 

[Ribcracker]

OK, tonights water results are:

Ammo 0.25
Nitrite 0.25
Nitrate 0.50

Should I do another large water change or just add StressZyme to break down the Ammo & Nitrite?

 

[OldMan47]

The chemical treatment will not remove the problem chemicals, at best it will keep the fish safer from the ammonia and nitrites while you deal with it. It is time for a significant partial water change to reduce both ammonia and nitrites. A 1 day build to that level probably means at least a 30% water change is needed.