Weird results during fishless cycle

[Clockwork-Crow]

Hi, I've been fishless cycling my 14 gal/65L aquarium for about 1.5 weeks, and over the last few days I've been seeing some very odd results. Yesterday I tested my nitrite levels, and they were clearly 0.25ppm, I tested them in the evening and they were back down to zero, but no change in the nitrate (still 0ppm) and couldn't really see a change in ammonia. I ran the same set of tests today, around the same time, I got a nitrite spike in the morning, but no nitrate, and ammonia hadn't noticeably decreased. I just finished another test about 4 hours later, nitrites were 0, nitrates were 0, and ammonia was maybe at3ppm down from 4. It's a reasonably well planted aquarium, with 2 anubias, 2 large jave ferns, and 7 stalks of egeria densa. Does anyone have any idea what's going on?

 

[Aiken Drum]

I wouldnt be overly concerned.

It doesnt take much ammonia to be cycled for you to see nitrite (1ppm ammonia to 2.7ppm nitrite). So your 0.25 nitrite is probably the result of a drop of 0.1ppm ammonia. That nitrite will also be producing a similarly small amount of nitrate, which is probably so small your test kit wont pick it up. Your 0.25 nitrite may result in 0.35 nitrate.

On top of all that your plants will be taking up some ammonia and nitrate, so that will affect your readings also.

1.5 weeks is only the begining for a fishless cycle, it could be 3 or 4 weeks before you see noticable nitrite and nitrate. Maybe longer in a planted tank because the plants are taking up both the fuel and end product.

 

[Clockwork-Crow]

Thanks. To be fair part of my confusion arises from the fact that I added both a small bag of sand from one of LFS's tanks a week ago, alongside 100ml of Tetra safestart, so was expecting to see something more significant by now. Also when adjusting my aquascape/trimming my egeria I can feel the slimyness that indicates biofilms.

 

[Aiken Drum]

The sand will help a little, established filter media in the filter would be better. The safe start might help a little too, at best it will speed up your cycle, but it wont instantly cycle your tank. At worst the safe start wont do anything. These products can speed things up, so a cycle takes 4 to 6 weeks, without them it can be months. Every cycle is different, people on here have done it in a couple weeks, others several months. 1.5 weeks is too short a time to tell where yours is going.

The plants will slow the cycle down a little, not that im suggesting you remove them. Turning the tank temp up can help. Optimum temp for the bacteria growth is 28 to 30c (83 to 87f). Remember to reset the temperature before you add fish.

 

[Clockwork-Crow]

Another odd thing I've noticed. This has happened three times now, I'll test the nitrites, and get a reading of <0.25ppm but definetly above zero, test them a few minutes after and get 0. Any idea what's going on here?

(I know it's >0 because I have started comparing my nitrite tests to a tapwater control and can reliably tell the tank water samples apart from the tapwater ones)