Aren't These Readings Odd!

[Gav_B_UK]

As the title states....aren't the readings in the chart below a little odd??? Can anyone explain this?

 

[keeper-of-fish]

what needs explaning?

the nitrates going up yes thats expected... to get those down u do more gravel vacs and water changes.

 

[Gav_B_UK]

Sorry...didn't explain correctly....I'm about 5 days in to a fishless cycle. I understand the nitrates should go up...but by 40ppm in a day??