Can A Tank Cycle In 20 Days?

[littlest]

It's been a while since I've had a tank but I've done fishless cycles before. I am setting a small tank (15 gal) and cycling with ammonia. Ammonia dropped to zero on day 7. Ben topping up to 4ppm daily. Nitrites peaked (darkest on chart) then dropped to zero on day 19. Today is day 20 and nitrites were zero about 16 hours since ammonia last added. If ammonia and nitrite are zero tomorrow am I ok to add fish? (After a water change). It just seems so quick

 

[Mamashack]

That would be quick unless you had started with some mature media or bottled bacteria. You'll need both ammonia and nitrite to be cleared within 24hrs after adding some ammonia. I'd add 3 pmm ammonia and see what it shows after the 24hrs. What's the nitrate and pH reading at the moment?

 

[littlest]

No mature media or bacteria. The only thing that went in was dechlorinator.

This morning I tested and ammonia and nitrite were 0 (after adding 4ppm yesterday evening). I added back up to 4ppm and will test again tomorrow morning.
I've not tested pH actually. I do have tests somewhere. Normally it's a tad alkaline round here.

 

[Mamashack]

It sounds like it's about almost there then You'll need to know pH really as it will affect what you can have in your tank. Good idea to keep regular check on all parameters and record them then you can maybe spot problems before they affect your fish.

 

[littlest]

Thanks - I tested this morning - about 20 hours after last adding ammonia. Ammonia was 0 and nitrite just had a slight tinge of colour to it - less than 0.1 but not quite zero either. So it seems like I am pretty close.
I found my pH kits and it's 7.8

 

[Mamashack]

You'll need to stick with fish that prefer slightly alkaline conditions then.
What are you thinking of getting once it's fully cycled?