Cycling

[Wasil Khan]

I'm a new member and a beginning aquapon.  I built a flood / drain system with a 300 gal fish tank and 150 gal total growbed with hydroton.  I put about 50 juvenile comet goldfish in initially to cycle things and am growing several plants.  After 3 weeks, I did a water test showing no ammonia, nitrite, and (somewhat concerningly) no nitrate.  I went ahead and ordered a hundred tilapia fingerlings which arrived 8 days ago.  They were doing well, but I then had one death 3 days ago.  It was comparatively small and thin compared to the other tilapia in the shipment.  Anyhow, I immediately tested the water and found ammonia up to 1ppm, NO2, NO3 still zero.   I bagged up some gravel from an established aquarium in cheese cloth and but these bags under the return flow to the grow beds.  Now I'm seeing a quick rise in NO2, and NO3 is now also showing up.  I've been doing 50 to 60% water changes each day for the past 3 days.  The fish seem active, are eating well and growing fast.  Plants seem also to be OK.  Should I just continue doing partial water changes until the NH3 and NO2 drop out?  How high can these get before the tilapia start to deteriorate?

 

Any advice is appreciated.

 

Wasil

 

 

 

 

 

[Wasil Khan]

Doesn't anyone have some thoughts on preserving tilapia through a system cycling?  Ideally, I should have measured water parameters until I saw evidence of the a complete cycle with the goldfish.  But now, I have tilapia in the system and obviously don't want to lose them...

[Keith Rowan]

water changes can interfere with the cycling process..just be patient, hold off on feed and monitor water parameters..

salt will help them deal with the stress, 3ppt

[Wasil Khan]

Thanks very much for replying, Keith.

 

Wasil

[Wasil Khan]

Just wanted to update this and say the system appears to have cycled.  The process is summarized in the chart below.  Some notes:

1.  The system was set up in early June with about 40 small comet goldfish and several plants (sweet potato, radish, Jalapeno pepper, cherry tomato, chive)

2.  Added 100 blue tilapia fingerlings 7-10-12.

3.  Daily 50-60% water changes 7-13 through 7-17-12.

4.  Seeded the system with gravel from an established aquarium 7-13-12

5.  Added approximately 2 cups of duckweed from a nearby pond 7-21-12

 

All fish survived the cycle, appear vigrous and growing well.  Plant growth became rapid once ammonia, NO2 and NO3 started appearing.