Cycling Question

[Lurch1]

I am on day 9 of my fishless cycle. I have a few plants and some old filter media. I also added the Live bacteria from BA (not impressed btw). My ammonia has been at .25 ppm for 2 days, Nitrite at 5 and the nitrate is at 40.

1. Should I do a water change at all before the cycle is complete?
2. When should I add more ammonia to feed the bacteria?

[Dakotamay]

Your water params are right on for cycling. Don't do a water change. Do a small water change once the ammonia and nitrite readings have reached 0. This will take the nitrates down a bit too.
The first thing in a cycle to spike is the ammonia. Next come the nitrite bacteria which takes the ammonia level down. Finally the Nitrates start to rise as those bacteria colonize in the water column.  So, it would appear your on track. With the nitrates being the highest. This is showing that you're bacteria stages are colonizing.
If you really wanted to  you could add some flake food for more fuel for the bacterias. Since there are no fish to provide an ammonia source.

[Lurch1]

I was actually using pure ammonia to cycle the tank. It worked quite well. I had an original ammonia reading of like 40 and then brought it down to 8 with water changes right off the bat. Potent stuff.

[exv152]

I am on day 9 of my fishless cycle. I have a few plants and some old filter media. I also added the Live bacteria from BA (not impressed btw). My ammonia has been at .25 ppm for 2 days, Nitrite at 5 and the nitrate is at 40.

1. Should I do a water change at all before the cycle is complete?
2. When should I add more ammonia to feed the bacteria?

Have you tested your tap water for nitrates? BTW any product that claims to sell "live" bacteria is lying.  Beneficial bacteria simply cannot survive in an enclosed bottle, it needs oxygen. The stuff they sell in bottles is just good to encourage bacterial growth but even that's highly controversial.

[Lurch1]

Yeah I was pretty sure the product was bogus, but thought it couldn't hurt. According to "Dr. Tim", they have the wrong bacteria bottled anyways. Yeah my water is 0 all around. My numbers were great today A- 0, Nitrite was 1 and Nitrate was 80. Sweet! I added more ammonia today to bring it back to 0.25 and hopefully I can add fish in a couple days.

[exv152]

The number one thing with cycling is patience. Don't rush it. One thing you want to be very careful with in your case is introducing fish to a tank that has high nitrates, this can be fatal for a fish that's comes from a tank with lower nitrates. I would try to get that below 20ppm, ideally 10-15ppm.

[Lurch1]

I was planning on doing a super water change, somewhere around 50% when the ammonia and nitrite have hit 0. I read somewhere that if you can cycle a dose of ammonia into nitrate in 24 hours then you are considered cycled.

[exv152]

I was planning on doing a super water change, somewhere around 50% when the ammonia and nitrite have hit 0. I read somewhere that if you can cycle a dose of ammonia into nitrate in 24 hours then you are considered cycled.

I have never heard of a tank being cycled in 24hrs, and I've been keeping fish for over 26 years. Cycling can be reduced by planting extremely heavily but still that comes nowhere near 24 hrs. Using mature filter media can also help significantly, maybe 2-3 weeks instead of 6.

[Lurch1]

I am on day 9 of my fishless cycle.

[Dakotamay]

as exv152 states. You need to have patience. The fact that you have now gotten a 0 ammonia, 0 nitrites and 80 nitrates reading means that you're almost there. As the final stage of bacteria colonize the nitrates will come down. You can do a small maybe 5% water change. But, if you do a 50% water change you've just removed half the water volume that the bacteria were colonizing in and replaced it with new water that then needs to be colonized again. So essentially you'll start your cycle over again. The tank needs time to mature. Small water change if you feel you really need to do one but ideally wait it out and let it mature. Patience.

[Lurch1]

As the final stage of bacteria colonize the nitrates will come down

I was unaware of this, I assumed that they remained high and required a water change to remove them. Where do they go? All is at 0 and not the Nitrates are at 20.

[Dakotamay]

The nitrifying bacteria consume the nitrates. They're at 20 today. That's awesome. Over the next couple of days they should go to maybe 5. Possibly even 0. Even now with a reading of 0 for ammonia, 0 for nitrites and 20 for nitrates. I would say you're cycled. But, don't hurry into adding fish. Make sure those readings don't spike again. Wait another 4 days or so of consistent readings and you're golden.

[bt]

The nitrifying bacteria consume the nitrates.

It's unlikely that denitrifying bacteria will remove nitrates in a FW tank.  The bacteria capable of doing so requires areas of very low to no oxygen to survive.  In SW, that will be a DSB or deep within live rock - both things that aren't typically found in a FW tank.

[exv152]

It's unlikely that denitrifying bacteria will remove nitrates in a FW tank.  The bacteria capable of doing so requires areas of very low to no oxygen to survive.  In SW, that will be a DSB or deep within live rock - both things that aren't typically found in a FW tank.

It's called anaerobic heterotroph bacteria, and it's common in deep substrate or sand substrates in particular in any aquarium beit salt or fresh. http://theaquariumwiki.com/Anaerobic

[bt]

Yeah, and it requires either a very dense substrate, or several inches of relatively fine substrate.  You might get enough substrate for it in a planted tank, but your plants would be doing most of the denitrifying at that point.

Gravel isn't likely to ever cut it, until it's so packed with detritus that you'd have far bigger problems than your nitrate levels.  Small gravel chips might pack together tight enough to provide an anaerobic zone, if deep enough.

[Lurch1]

So what is the consensus then, should I do a pwc and add my pleco or wait it out until the nitrates drop?

[Dakotamay]

In my opinion the tank is cycled. I'd just wait a few more days to make sure. Then if the nitrates stay around the 20 or lower you could do a small 5% water change and then add your pleco. Give it a week after the pleco and then add a few fish.
IMO you're cycled and good to go. It just never hurts to air on the side of caution and watch the readings for a few days to make sure.
Good luck and enjoy your new tank 

[Lurch1]

Thanks for your input!