by Rockfish » Thu Feb 11, 2016 12:07 am
Hi Claire,
Welcome to the forum and sorry to hear you are having this issue.
It's a good thing the pH levels aren't any higher otherwise the switch in the ratio of ammonia:ammonium would almost certainly be rapidly fatal. Even so, that is an extremely high level as I'm sure you already know, so my first thought is have you checked the level with a conventional ammonia kit to confirm the Seneye reading? (Not all standard aquarium kits allow you to distinguish between ammonia/ammonium without pH charts but it would still give an idea if the total amount is really that high).
Moving and cleaning the tank will clearly have caused the spike, saving a good proportion of the water isn't a bad idea, but won't make any real difference to the population of filtration bacteria. Even though the filters were washed in tank water, the combination of that with cleaning the tank and substrate etc has obviously knocked the bacteria down to a level that it can't handle the bioload yet - especially if extra fish were added around the same time.
With mature filter media, you would expect the recovery to be fairly quick, because it's not like starting from scratch with a new tank, but another problem you may have is that when the ammonia/ammonium level is really high, it can actually inhibit the ammonia-converting bacteria themselves, so it can stall the recovery process. The only way to combat this apart from physical removal with zeolite etc (as opposed to things like Prime that bind/convert but still leave as measurable, albeit safer, levels in the tank) would be to continue large water changes to remove as much as possible. However, you need to make sure the change water is as similar to the tank as possible, and don't remove too much at once as you don't want to risk affecting the filter bacteria any more than necessary. For that reason, I wouldn't clean the filter at all unless the flow slows significantly.
In addition, I would stop feeding to minimise wastes. Several days without food won't do the fish any harm, and they may not have much appetite in any case.
The NH3 might not be changing in a totally predictable manner with the NH4 due to either variations in the accuracy of detection with the sort of numbers you're dealing with, or due to the ratio changing with minor pH changes that might be hardly detectable, but would still change the numbers a little due to the amounts involved.
So I would say continued large water changes, don't touch the filter unless necessary, minimise feeding and it might help to add extra bacteria if possible if you have access to any mature media, substrate etc from a different mature tank, or some bottled bacteria products might help, but bear in mind that with either of these things, the bacteria added may still be inhibited by the very high ammonium levels.