Fishless cycle appears complete...change substrate now?

[Graybeard]

Ammonia dropped to 0,

Nitrite off the chart

Nitrate at 50

I started with natural looking epoxy coated gravel and later found threads on using playsand even in FW tanks.

I want to do a PWC so that will make it easier to remove the plants and driftwood. My thought is to stir up the gravel and allow the HOB to filter the water for about fifteen minutes, turn off the HOB, remove gravel and replace it with the playsand, replant and add the water I saved back to the tank.

Anything else?

 

[Simpte]

You will experience another cycle when you do. Much of the bacteria is in the mulm (gunk in the gravel) and on the plants themselves. I do find it off that your NO3 reading is that high with plants. Stirring up the gravel will lead to a greenwater bloom also. I would just drain the tank, change substrates (keeping a cpl of handfulls of the old stuff) and place that in a stocking ontop of the sand. This will help seed the new substrate (not that much bacteria will be residing there).

 

[7Enigma]

Your fishless cycle appears to be only 1/2 complete right now. Your nitrIte levels suggest that while you have a good amount of the 1st type of bacteria, you still need high levels of nitrIte to nitrAte converting bacteria. Since your cycle is still a ways off, I think you could safely replace the substrate since a large majority of your bacteria are established on the filter.

If you were to have a fully cycled tank and wanted to add fish tomorrow, then I'd recommend AGAINST a substrate change, but since you probably have at least a week (this is being very optimistic) you won't affect your cycle much if at all. The biggest problem is that you will lose some of your ammonia to nitrIte bacteria, but this doesn't matter since you have a while to let those numbers grow since your nitrIte is still off the chart. I'd argue that while it would have been better to do the sand substrate before starting to fishless cycle, this is probably the best time to change (before bacteria completely established, and definately before fish are added).

Oh and you need to keep adding ammonia to the tank in a low dose (1-2ppm) so that the ammonia converting bacteria don't die off while waiting for the nitrIte converting bacteria to become established.

justin

 

[bosk1]

7Enigma is entirely correct.

 

[Graybeard]

Simpte...

No live plants.

It's a fishless cycle, will there really be a lot funk in the gravel?

7Enigma...

Ammonia dropped to 0 last night. I will add 10% to bring it up this afternoon. I was guessing at the state of the cycle but knew that I should replace the substrate ASAP.

With frequent PCW's, and bacteria available to consume the ammonia, can I add the Cory's to appease my wife and kids?

 

[rich311k]

Do not add cories with your nitrites off the chart. Bottom dwellers are even more effected my the toxins available in an uncycled tank. I would finish the cycle and then add your fish. I would wait intil several weeks after the tank is cycled before you change the gravel. Give the filter a chance to colonize as much as possible.

 

[7Enigma]

Agreed, do not add the cories.

Make sure you only add a little bit of ammonia (no more than 2ppm). In a couple of days I'd do a 90% water change to bring the nitrIte's down. Trust me, there is nothing more disheartening than doing nitrIte tests every couple days and never see that color change...You might have 20ppm or more of nitrIte and even if your cycle is technically "finished", you would never know since dark red looks just like slightly less dark red (say 20ppm to 18ppm in 24hours, but then you dose with ammonia again...). What you want to do is get as much of the nitrIte out of the tank as possible, while only taking out the minimum amount of bacteria at the same time. So don't stir up the substrate too much, or mess with the filter when taking the water out. 2 days ago I thought I still had a long time to cycle, but today I'm technically finished.


Since you are doing this with no fish head over to my thread if you want to read the method I used. FYI it took me ~16days from start to finish, with some gravel from a friends tank helping to start the cycle. During this time have your kids plan out what exact fish they want, get them to draw pictures, take them to the fish place and have them pick out fake plants, teach them about how fish eat/sleep/interact with each other....ANYTHING but actually get them fish.

Explain that the fish would be harmed if you got them too soon, or that they would not be happy (sorry I don't know the age of the kids).

As for your wife, tell her it won't stink up the house if one goes bellyup in the night from the ammonia or nitrIte in the water......that should work.

 

[Graybeard]

I re-read my own post and see that the cycle is still incomplete.

We can all wait on the fish.

 

[TDWagner]

In a couple of days I'd do a 90% water change to bring the nitrIte's down. Trust me, there is nothing more disheartening than doing nitrIte tests every couple days and never see that color change...You might have 20ppm or more of nitrIte and even if your cycle is technically "finished", you would never know since dark red looks just like slightly less dark red (say 20ppm to 18ppm in 24hours, but then you dose with ammonia again...). What you want to do is get as much of the nitrIte out of the tank as possible, while only taking out the minimum amount of bacteria at the same time.

What's the purpose of a big water change during a fishless cycle? Don't you want those Nitrites in there so the second type of bacteria will grow?

 

[7Enigma]

The purpose is two-fold.

1. I have read about a negative feedback inhibition where very high levels actually inhibit the bacteria from multiplying (I have no idea how true this is, but #2 makes this a moot point).

2. It is impossible to see a difference between 18ppm and 20ppm of nitrIte in any of our liquid or strip testing kits. You could very well be completely cycled, but due to the lag time between when the ammonia converting bacteria multiplied, and when the nitrIte converting bacteria multiplied, you will have such a surplus of nitrIte that it takes a long time to come back to readable levels. For example, I have technically been done cycling for over a day now. Before my PWC I had at least 20ppm nitrIte in the tank. Had I not done that water change, I would still think that it was cycling.

This only applies mind you, if you have been continuously dosing ammonia, and IMO, this is the fastest and best way to have a cycled tank. Reason being that some of the ammonia converting bacteria will at best stop dividing (at worst begin dying), while your waiting for the nitrIte bacteria to multiply. If you keep adding ammonia during the entire cycle, your ammonia converting bacteria never stop multiplying. But then you develop a really high nitrIte level and hence the PWC.

 

[TDWagner]

That makes sense. The fishless cycle article I read just said to sit there and wait for the nitrites to come down to 0...no matter how high they go. It makes sense though that they only need to be able to convert like 2 or 3 ppm per day.

You probably just saved me a couple of weeks of empty tank staring!

I knew there was a reason I joined this forum!!!

 

[bosk1]

I agree with the water change for the reasons stated.

 

[7Enigma]

I had read the same opinion on several different sites (including this one) and it didn't make sense to me. Why starve 1 type of bacteria while waiting for the other to finish feeding? Seemed a bit dumb IMO.

Now here's a thought for a great product. Sell NitrIte to add to the water. I'm pretty sure that you could shorten your cycle a couple days by dosing with both ammonia and nitrIte from day 1. The nitrIte to nitrAte converting bacteria multiply almost twice as slowly as the ammonia to nitrIte bacteria, and as such, it would make sense to supply them with food at the very beginning of a cycle. Hmm....think I've found an untapped market....nah, I'm sure someone sells it.