Cycle Going Unexpectedly Fast?

hiya!
 
currently cycling a new 200l tank with a fluval u4 internal filter. added a small (now inert) carbon sponge from old juwel canister to speed the process up a bit along with three rocks from existing tank, albeit only a week ago. have also got a fair few plants in the tank and some bogwood as you can see in the attached image and have been using 9.5% ammonium hydroxide to cycle. my question is regarding the speed at which things seem to be happening as it seems rather faster than i imagined. if i could get some opinions id appreciate it! my readings since the start are as follows:
 
day; Ammonia ppm; nitrite ppm; pH; liquid ammonia dose;
 
1; 3.0ppm; 0ppm; 8.2; 4.11ml (only have 130l of water in tank atm)
2; N/A
3; 2.5ppm; 0ppm; 8.0; 
4; 2.0ppm; 0ppm, 7.8
5; N?A
6; 1.0ppm; 0.1ppm; 7.5
7; 1.0ppm; 0.2ppm; 7.5
8; N/A
9; 0.25ppm; 0.35ppm; 7.5
10; <0.25ppm; 0ppm??; 7.5; 4.11ml (after days readings)
11; 2.5ppm; 0.25ppm; 7.4
12; 0.5ppm; 2.0ppm; 7.4
13; <0.25ppm, 2.5ppm; 7.4 (could be zero ammonia, hard to tell 0 vs 0.25 on API test kit sometimes)
14; <0.25ppm; 0.25ppm; 7.4
 
my main concern today was the change from 2.5ppm to 0.25ppm of nitrite that quickly and only on day 14. is that expected? im guessing the plants are consuming some ammonia but cant explain the nitrite
 
thanks again for any input. really wanna get this cycle right for the sake of the fish!
 
edit: yes there is a fair amount of nitrate too; about 30ppm last i checked

It does look good, I must say, but the level rose quite a bit from day 10's 0ppm, so I would give it another snack dose of ammonia, and see what the nitrite reading does then.

yeh was wondering why it was coming and going so rapidly. thought nitrite would rise and peak over a week at least! guess its the established stuff i added. so chuck the 1/3 dose in now and test again tmr? also forgot to upload pic of tank so will do here in case it helps understand whats going on due to planting etc
 
thanks for response!
 
also the day 11 reading of nitrite at 0.25ppm would have been about 16 hours after i added the second ammonia dose the day before which would also explain the drop from 3ppm to 2.5ppm ammonia over night? does that make it more acceptable?

Your cycling does seem to be progressing somewhat, though a little confusing. I agree with thelockman and dose snack dose of ammonia, 1ppm, and see what results occurs from that.
 
Can I ask for nitrate test results if you have any of that?

just tested nitrate and again its not the easiest to read on api chart but i think its around 20ppm. guessing the plants are gobbling it up? also just added the 1/3 ammonia dose so will see if there is any left tmr

Ch4rlie said:

Your cycling does seem to be progressing somewhat, though a little confusing. I agree with thelockman and dose snack dose of ammonia, 1ppm, and see what results occurs from that.
 
Can I ask for nitrate test results if you have any of that?

Click to expand...

 so 5 hours on from snack dose addition and half of the ammonia is gone (now 0.5ppm) and nitrite is still 0.25ppm