Mini-cycle After Change From Gravel To Sand?

[RMcdowell]

Okies,
Ive got a 4 foot tank thats been running fine for years (PH 7.2, Ammonia 0, Nitrites 0 and Nitrates 5).
It used to have gravel with a UGF powered by 2 X 1000L powerheads + a Fluval 2 and a Fluval 3+ filter wise.
Ive changed the gravel to sand (Ditching the UGF and Powerheads) following the excellant thread on these
forums on how to do it.
Ive also added a 2nd Fluval 3+ filter, that im currently running alongside the fluval 2 at one
end of the tank, and will remove the fluval 2 in 3-4 weeks time (once the bacteria has built up on the new fluval 3+) - im
intending to run a fluval 3+ at each end of the tank.

I did a 30% water change (Dechlorinated of course) same time as I did the change over and I fully washed the sand till
totally clear (Dechlorinated water for final rinse) - Argos Playsand.

Water stats +5 hours after change to sand = PH7.2/Ammonia0.25/Nitrite0/Nitrate20
Water stats + 1 day after change to sand = PH7.0/Ammonia0.25/Nitrite0/Nitrate7.5
Water stats + 2 days after change to sand = PH7.0/Ammonia0.50/Nitrite0.25/Nitrate5

Im assuming im going through a mini cycle as the fluvals now have to pick up the slack left over after the removal
of the UGF?

Starting to get a little concerned about the ammonia due to the fact in my community tank ive about 40 cherry/amano shrimps.

How would you guys proceed?? Water change??

 

[minxfishy]

Yep sounds like you lost some bacteria with the removal of the UGF, it happens.

Hopefully it should only be a small mini cycle that you get as you still have the mature media in the fluvals.

You should continue the water changes, 50% daily to get the ammonia and nitrIte to 0.25ppm or lower if possible until the filters catch up with the waste load.