Just tested water, inadequate filtration?

[David R]

800L tank, filtered by a wet/dry trickle filter, pump doing about 6150lph, more details here, stocked with;
~15" green aro
~17" ornate
13" and 6" indo dats
12" tyre track eel
11" Uaru (female)
2 6" A. heckelii
5" "surinamensis"
4" balzanii
3" royal plec

The tank was set up 3 weeks ago, although 1/3 of the water, the substrate, wood, and filter media (and fish) were all from my 160g which had been running for ~10 months and should have been well established. I've been doing 250-300L water changes every 5-7 days since it was set up, and I was thinking there may have been a bit of a mini cycle from the move, but I thought by now it would have been over. I tested the water before doing a wc this morning and the nitrite was 0ppm, ammonia ~0.75ppm and nitrate only about 10ppm. The fish are fed a mix of raw shrimp and pellets, and I don't over-feed. The sump has about 29L of media, bioballs and pumice, with about 1/3 submerged and 2/3 above water.

The high ammonia has got me thinking, and if its not caused by a die-back in bacteria following the move (which I thought it should have recovered from in 3 weeks) then perhaps I just don't have enough bio media? I've been thinking about modifying or replacing the sump so I can set up a continuous drip system to reduce the time water changes take, so perhaps I should upgrade to one with a much larger bio chamber?

 

[12 Volt Man]

sound like its just going through a mini cycle. if the filters/substrate supported the required bacterial population in the 160, they will do the same in the big tank. but it might take some time to build the population back up thats all.

just keep doing what you are doing (water changes and don't overfeed) and the tank should be fine. as your fish grow in the bigger tank and eat more, the bacterial population should grow accordingly.

 

[David R]

Thanks. I've found a source for cheap ceramic media so I might add a basket in the sump and put some in there.

Another thought I had was that my sand/grit substrate could be a too thick. Its about 1.5-2" deep, and I usually give it a good stir every other waterchange to try and keep it clean, buts hard to get all the fine particles of waste out of it. I might take some out .