Cycle Completed, Or Almost Completed?

[Fisho]

I've been cycling for about a month now and over the last few days Nitrites and Ammonia seem to be dropping from 3-4 to 0 in about 12 hours. I was going to get a lift from a friend and get some fish today since it seemed like my cycle had pretty much finished. Unfortunatly this morning I found a very low nitrite reading, like maybe 0.1-2ppm. I'm going to test again in a few hours and I'll be doing a 90% water change before I put the fish in the tank. Is it safe to get fish with these sorts of readings? I'm not going to be getting much, maybe a few honey gourami's or a small group of tetras and its a 70ltr tank. Any help would be great, the shop I'm getting the fish from is quite a distance away so I'm hoping that I won't have to re-arrange as it could be quite a while before I could make it out there again.

Any advice would be great.

 

[Lynda B]

You should have 0 ammonia and 0 nitrites before adding fish.

What were you planning on getting for your first fish?

 

[Fisho]

B)-->QUOTE(Lynda B @ Jul 12 2007, 02:10 PM) [snapback]1688479[/snapback]
You should have 0 ammonia and 0 nitrites before adding fish.

What were you planning on getting for your first fish?[/quote]

I know, but I've had 0 ammonia and nitrites yesterday and the day before, and I'll be doing a 90% or more water change a few hours before I put the fish in so there'll basicly nothing in the water anyway. I'm planning on getting a small group of tetras (6 probably) or maybe a trio of Honey Gouramis.

 

[Lynda B]

I have serpaes, red eyes and black phantom tetras. They're pretty hardy. You might be okay.

I don't know anything about gouramis, other than they are beautiful.

 

[rdd1952]

If you can add 3 to 4 ppm of ammonia and in 12 hours, your ammonia and nitrite readings are both zero AND your nitrates have risen, then your cycle is complete and you are ready for fish. Just do the big water change and you are ready.

What is your current nitrate reading?

 

[Aphotic Phoenix]

Sometimes you'll get little fluctuations like that on a tank that is nearly finished. If you can't wait to get fish just keep a close eye on everything, doing a test in the morning and evening so if you need to do a water change for some reason you can.

 

[Fisho]

Hey, I didn't end up getting fish today anyway, just decieded it was better to wait a bit longer and make sure everything is going ok. Thanks for all the help everyone

 

[orange shark]

could you post your full water stats so we can help?

 

[Fisho]

Yeah sure, at the earliest I'll be getting fish on Monday so I'm just going to keep monitoring everything until then.
This morning was pretty much the same after I added ammonia to about 3-4ppm in the previous evening.

Ammonia-0
Nitrites-Very slightly pink- 0.2-3
Nitrates - 5-10ppm (My test for this isn't great)

I carried out a 90% water change last night which is why the Nitrates aren't so high.

It seems ammonia is dropping fine, but while Nitrites are definatly dropping there just not dropping quite as fast.

 

[orange shark]

I think you should keep adding ammonia until the nitrites eventually go down to zero. (can someone confirm this for me?)

orange shark

 

[DarkEntity]

ONce a cycle is complete you will have Zero Ammonia and Zero Nitrites with a slight Nitrate reading. Do large water change and you can safely add a few hardy fish. after a coulpe of weeks add a couple more fish and so on.

dont rush it as you need to build up the good bacteria so it can cope with the new waste the fish produce.

 

[Puffdaddy]

There are in fact two types of beneficial bacteria you are trying to grow the first is nitrosomonas which converts ammonia to less harmful nitrites. The second type of beneficial bacteria is called nitrobacter which converts the nitrites to even less harmful nitrates. The nitrates are then removed by water changes. You have stated above that 3-4ppm of ammonia is consumed after 12hrs with some lingering nitrites still present. Soooo that would suggest that your nitrosomonas has fully developed and you nitrobacter still has a little bit to go. When 3-4ppm of ammonia has been consumed in a 12 hour period with no ammonia and no nitrite readings then add fish within the next 24hrs after a large water change. With the amount of ammonia you were using for the fishless cycle, you could safely add the 6 Tetra's or 3 Honey Gouramis you are shooting for.
Good Luck!

 

[rdd1952]

As Puffdaddy mentioned, once your tank is to the point that you can add 4 ppm pf ammonia an din 12 hours you have zero ammonia and nitrite, you are ready for your fish. Continue to add ammonia up til the day before you get your fish. Add it that morning. It should be all zeros that evening, do the water change to lower nitrates and then add 75 to 100 percent of your fish the next day. If you have used 3 to 4 ppm of ammonia the whole time, you will hve plenty of bacteria to support a full fish load.