Has my Cycle Stalled

[Kym a]

I was hoping someone could explain to me why my New tank I`m cycling has not progressed as expected.
It is a Juwel 450 Vision which come standard with a Large Internal biological filter with a pump with a 1000 Litre ? hour rating.
I set the Tank up in late October with Moderate to heavy planting and no fish.
A week later I added 3 small Rainbow fish after unsuccessfully trying to source Pure Ammonia.
2 weeks after that I transfered the contents of a 3 foot to this tank.
At that time all water readings were 0 and the PH 7.2
The fish transfered over were 6 Medium Rainbows, Pearl Gourami, (2) 4" Bristlenose 2 SAE and a 6" Ghost knife fish.
A few days later the Ammonia rose to .50ppm but no sign of Nitrite or Nitrates
I immediately done a 50% water change and added some Stress Zyme to try and increase the Bacteria level, the Ammonia level has remained a .25ppm consistently since with still no sign of the next 2 steps in a normal cycle.
I have added the Eheim Filter that was running on the 3 foot and is fully cycled from that tank which was in operation for the last 10 months with perfect readings for Ammonia & Nitrate of 0 and Nitrates were ever only around 5mg/l.
This filter is running on the opposite side of the tank from the Internal which is also operational.
I have been doing weekly water changes of 25% since this started.
The ph remains 7.4 to 7.2
Is it that the plants are buffering the Ammonia & Nitrite levels before they can develop to the Nitrates, the plants are all growing very quickly and the fish do not show any signs of stress.
I have just purchased a Eheim 2217 which is to be run on this tank however I was hoping it would be fully cycled before I changed any Filters over.
Any suggestions would be welcome.

Kym a

[fins_n_fur]

Nice tank! I have the same one--it's about 120 gallons.

Note that I'm not 100% sure, but I suspect that your plants are using the ammonia and nitrites as nutrients (food) in the water column causing your cycle to be slower. I'm not sure that it is stuck, rather than just cycling slower with the plants (sometimes called a silent cycle). What are you going to do with the Eheim from the 3 foot tank that you have on the 450 temporarily? What size filter or model is it? I would think that you could take as much of the filter material in that filter and put it in the 2217 to have a nearly cycled filter. I hoped this helped somewhat. Also, is it your plan to removed the internal filter that came with the 450?

[Kym a]

The old Eheim Filter is a 2013 which was rated at 390 litres with probably about 1/2 the capacity for Filter material as the 2217 so probably would need a bit of time also to become fully biologically efficient.
I was hoping to run just the internal filter but after reading varying reports on their capacity if you have a large population of fish and the fact they skim from the top I will probably run both the Filters to hopefully keep Water variations mimimal.

Kym a

[fins_n_fur]

I didn't like the amount of room it took up, so when I had the opportunity to replace the internal with a 2180 I jumped! LOL Also, I'm pretty sure that the internals do not only top skim, but take in water from the bottom as well (you should see vents in the bottom part). Agreed that it may be enough for a light to medium stocked tank, probaby not enough for a full stocked tank. Whatever material that's in the older Eheim will definitely speed up the cycling of the new Eheim.

[Mvjnz]

If you added a cycled filter then that filter is processing all the ammonia and nitrite, and the plants are prolly using most of the nitrate.

[Kym a]

Just a quick update about my cycle.
I appears to have been completed a couple of days ago, the Ammonia tested 0 as did Nitrites & Nitrate, Never noticed a reading for the last two but as is the common belief the plants have probably been using them as nourishment.
I did install the new Eheim Filter after seeding it with most of the material from the old filter which also may have helped.
I`ll post Photos in the near future once happy with my setup.
Thanks for replies and suggestions.

Regards
Kym

[Lady Hobbs]

When you began to stock, stock about 6 fish per week to keep things in balance. Sounds like you finally got-r-dun! Good job.