Some random thoughts on tank cycling.
Your tank is never done cycling....it's not like you do it once and it's done forever.
When you cycle, what you are actually doing is establishing a healthy bacteria colony in the tank that
has the ability to slow down the rise of pollution within the tank. You can never achieve
a total balance, which is why we water change. Not only do water changes recharge some of
the trace elements within the tank, but water changes are necessary to dilute the amount of
toxic chemistry in the tank and keep it down to a level that won't kill the fish. You can aid this process
by having adequate water movement at the tanks surface which will facilitate the exchange of good & bad gases
within the tank.
Back to the cycling. Your tank will actually have a mini-cycle every time you have a change in the bio-load within the tank.
If you add more fish to your community, you add bi- load and the ammonia, nitrate, nitrite cycle will occur again. Maybe not
to the scale you see with the initial cycle, but you'll see a bump in your numbers. Wanna bump the numbers on purpose?
Just toss a hand full of flake food into the tank that's larger than the inhabitants can consume, then wait a couple of days, then test.
Keeping filters too clean can destroy the bacteria colony too, so that can help bump the numbers, as can gravel washing, which is why
you should never gravel wash more than half your tank at a time. Loss of power in the aquarium can cause a re-cycle too if the bacteria expire.
That's why we water change during power outages...tap water spilling into the tank will help oxygenate the aquarium, especially if you use cold water.
BTW.....for those of us who think they are experience aquarists....who's got a generator? You've got hundreds invested in your fish. Have you ever thought
about going to a discount tool store such as Harbor Freight and spending $150 on a generator in case you lose power? It's an easy sell to your non-fish loving spouse.
You can always get it to keep the fridge cold and the tv on. I'm just saying.
The bottom line is not to spend too much money on test kits, nor too much time worrying about the cycle or nitrite levels. Fish can handle higher nitrite levels
than ammonia or nitrate. We've all lost fish due to bad water for one reason or another, but I've never heard anyone claim to be losing fish due to nitrite.
Kyle "non-test kit owning" May
Ohio Cichlid Association
Northern Ohio, USA