It's really frustrating isn't it, I'm going through very similar circumstances to you with my fishless cycle, and if I had any hair to waste I'd have pulled it out in clumps by now.
I'm on day 56. The first 13 days went great with Ammonia dropping to zero, and Nitrites were peaked out at 10 for a few days, then were just starting to drop. The problem was I wasn't really checking Ph as it had been stable since the start, then suddenly everything went wrong. Ammonia was back up to 2ppm after 24 hours from daily dose, the Ph had dropped to 6.0 and checking on here meant a diagnosis of bacteria stalling was reached. There was a big lump of bogwood in the tank which was the cause, so out that came and a full waterchange/cleaning etc was carried out.
The cycle started again pretty quickly, 4 more days and I was processing Ammonia down to zero after 24 hours, with Nitrites down to zero after 7 days (24 hour mark). The 12 hour measurements showed Ammonia 0.25 and Nitrites 0.5 so things were moving. Then I bought one of those plastic tree roots, you know the sort....big thing with loads of hidey holes for the fish. I obviously gave it a good wash, in ordinary tap water, and as it's hollow there was loads of lovely chlorine laced water left inside to mix into the tank
Ammonia was back up to 2ppm after 24 hours. Another water change. This was day 34 of my cycle. The ornament was removed.
It took 7 days for the ammonia to go to zero (24 hours) and the nitrites took 12 days to get to that point. the 12 hour measurements were just starting to look batter when I decided to change 20% water because there was a lot of what looked like soap suds on the surface and the nitrates were really high.
My ammonia is still processing back to zero in 24 hours, but my Nitrites have slowed right down, from zero at 24 hours to 0.5 at 24 hours. It's been like this for 4 days. (I'm laughing or else I'd cry).
How bloody frustrating is this? It sometimes seems that it's a waste of time, if I'd waited until after the cycle was finished these problems with water changes etc would still happen. So how do you finish a cycle, re-fill with nice new water, add your plants and ornaments then avoid putting your fish into what is then an un-cycled tank?
I'm always really careful with the water btw. The tap water is Ph 7.0, Amm 0, Nitrites 0, Nitrates 5 and I add the Tetra Aquasafe at 1.5 dose with a syringe dropper so it's spot-on.
Sorry to hijack with a long thread. I needed to get it off my chest.
