Problem Cycling HUGE Tank

[turbovr6]

Hello AA members,

Not being a newbie to cycling, I have cycled quite a few "normal" sized tanks in my life. Now I am trying to cycle my 600 gallon indoor pond.

I was going to take a shot a cycling with pure ammonia but just could not find any! So I went with fish food and raw shrimp, a method that has always worked for me in the past.

So my pond..... I filled it up, treated with Prime, got the ammonia up to 2.0 and then added Stability in the correct amounts for 8 days...NOTHING! Ammonia stayed at 2.0, never seen nitrites, nitrates would go to 5ppm some days, then back to zero. After 2 weeks or so I took a bunch of gravel, bio media, and sponges from two of my established tanks and placed everything in the wet/dry sump filter. It's been another week and the same exact thing!!! No change!

Does the amount of water usually determine the time to cycle? I know it can take quite some time to cycle but I have been testing every day and it is always the same. Ammonia 2.0, nitrites zero. I am using the API master kit, I know it is good because everything in my other tanks test correct.

Pond specs: 600 gallon, temp 77-78 degrees. 2400GPH pump, 75gal sump.
PH 7.2.

Any advice or suggestions would be greatly appreciated! I have a big fish that needs to start his life in the new pond!!!!

 

[jsoong]

Well, at 78F it will take longer to cycle than tropical temps. When I cycled my 1st tank, it was close to 10 weeks at mid 70's.

However, do you really need to cycle the pond like a normal tank? When you cycle a tank, you would grow a bacteria colony that can handle a full bioload of the tank. Now the full bioload of a 600 gal pond is huge, so I would think it will takes a while to grow that big of a colony. But you probably won't need to grow that big a colony since your fish will not be maxing out the pond's bioload.

If your fish is currently in a fully cycled tank, that tank would have a big enough colony to support the fish's bioload. If you move everything (filter/substrate/etc) from the tank over to the pond, you should have enough bacteria to handle the fish & not see a cycle spike. Leave everything in the pond for 6-10 weeks & the bacteria will migrate to the pond & can grow as you add more fish.

Anyway, this is how I had moved fish from small tank to big. I do monitor the water chemistry closely for the first few weeks just in case, but had never even have a mini-cycle. This is one way to get a tank (or in your case pond) ready without a lengthy cycle.

PS - you might want to head over to the pond section to see if the ponders have any more tips.

 

[turbovr6]

Thanks for the tips. I have considered moving the fish and the canister filter from the cycled 125 to the pond. I just worry about ammonia and nitrite poisoning as well as the massive amount of waste this guy produces and the fear of having to do 200 gallon water changes every other day!!!
I guess it makes sense that if the water params are fine now with just one fish moving everything to the pond should not make a difference.