Odd Readings While Cycling

Stop adding ammonia.

Adding ammonia except when certain targets have been reached just makes so much nitrite that the cycle stalls. Nitrite stalls the cycle around 15 to 16 ppm. As 1 ppm ammonia is turned into 2.7 ppm nitrite, it doesn't take much ammonia to get to stall point.
The tester scales will show the highest reading no matter how high the level actually is.
The method on here (which I feely admit I stole from somewhere else) says to add ammonia only when certain targets have been reached, and if followed carefull will not allow nitrite to reach stall point.. https://forums.thinkfish.co.uk/fishtank-filtration-and-cycling/fishless-cycling-how-to-do-it/


As you now have plants I would do a total water change to get rid of the ammonia and nitrite and get nitrate back to tap water level. Then plant the plants. Take a photo and go and do something else for a couple of weeks. Do not add any ammonia.
After a couple of weeks, compare the photo to the tank to see how much the plants have grown. If there is a good amount of growth, you can get the first few fish. Keep an eye on ammonia and nitrite for several days afterwards.



The reason for not adding any more ammonia is twofold.
Many plants cannot tolerate ammonia at 3 ppm (the amount that should be added for fishless cycling). Fish make ammonia in tiny amounts 24 hours a day. It is removed as soon as it is made so there is never enough in the water to show up in the test. Adding ammonia from a bottle may add the same daily amount, but all at once so the level shoots up, then slowly drops. It is this high initial level which harms some plants.

Plants prefer ammonia as their source of nitrogen, and they turn it into protein rather than nitrite. If more ammonia is added than the current plants can take up, bacteria will grow and convert the surplus into nitrite. This will remain in the water until enough nitrite eaters have grown to remove it, and growing the nitrite eaters is a slow process. Fish cannot then be added until nitrite drops to zero, which is a lot longer than waiting till the plants are visibly growing.

So 2 things went wrong here:
1 - I added too much ammonia & stalled the cycle
2 - The plants threw the method out the window
Is that about right? : ??

That's about it.
Older methods of fishless cycling say to add 5 ppm ammonia and to add more whenever the ammonia reading drops to zero. More recent knowledge says that a tankful of fish makes less than 3 ppm a day, so 3 ppm grows more bacteria than are actually needed.
We now also know why cycles stall when too much ammonia is added - nitrite inhibits the nitrite eaters.
Plants do change things because they take up ammonia faster than bacteria. This can fool the fish keeper into thinking the ammonia eaters are growing well. Ideally, if a fishless cycle is done plants should be added after it's finished. Or use the plants to do a silent cycle with no added ammonia.



Can you squeeze all the old media into the new filter, even if it means cutting part of the new media off? You will already have grown some ammonia eaters and possibly a few nitrite eaters so it's worth hanging on to them. They won't die off while you are waiting for the plants to establish (Another belief from years ago is that the bacteria die in 24 hours with no food, but they actually live for months)
Even with a jungle of plants, bacteria will still grow slowly in the background, just not nearly as many as in a tank with no live plants.

The usual recommendation is at least 4 weeks.

If you do a fishless cycle with ammonia, it can be taken out straight away as all that will do is make it take a bit longer; but with a plant cycle, I would leave it in there until a couple of batches of fish have been added, then remove it but wait a bit longer till the next batch of fish to be on the safe side.

I tend to favour the "make sure it can cope with the worst case scenario" way of doing things, rather than "it'll be OK, just do it" way. My husband calls me a pessimist so I always expect the worst to happen.

Strips don't have the best reputation. If they get damp they can give false readings.

Have you tested some tap water that's been allowed to stand overnight?

Do you know the KH of your water? Nitrite and nitrate are acidic and if KH is low they will use it all and with nothing left to buffer the water the pH will fall.

Good plant growth 

Agree that it would be good to check your KH.

Water supplier says
Water hardness average: 128.3mg/l calcium
pH (Hydrogen Ion Conc.)   7.3

Sorry, forgot to mention I did that earlier today & the strips were identical.  It was fresh from the tap not a day old as Sue suggested, will try that in the morning.
Gonna need some new liquid based tests I think.

Your tank looks good, and your plants are doing well too.

I mainly use liquid tests, but when using strips I would use paper towel to remove excess water in a similar manner to how Matt describes tapping the strips on the tank.