Cycling my 75 gallon tank bump in the road

[friendly75]

First off I wanted to say hello to all. Your site has been a wealth of knowledge and inspiration. I really didn't think I was going to join but... two reasons. First cycling a new 75 gallon tank with a 15 gallon sump can get a lil boing, and I have hit a little bump in the road where I could use some advice.

Currently I am doing a Fish-Less cycle I have a 75 gallon tank, 15 gallon sump which half is bio balls and the other is my pump which pumps 330gph. I am on day number 8 using pure ace hardware ammonia. I dosed to approx. 5ppm and to my surprise on day number 4 I saw Nitrites, day 5 I saw 2ppm Nitrites and between 40 and 80ppm Nitrate. Also on day five I got a hold of some substrate/gravel from a five year old tank, I was lucky to get about 20lbs.

Now day 6 ammonia level around 3 to 4 ppm, Nitrites 2ppm Nitrates climbing, upwards of Nitrate 100ppm.

Here is where I think I know what going on but want to make sure. Day 8 ammonia between 1-2ppm. but my nitrites have almost disappeared. I figure there is a logical solution and maybe the person I got the substrate from had treated it with some sort of medicine at one time to help a nitrite problem, or my ammonia level is dropping too low thus the drop in Nitrites. Or maybe none of the above

Sorry for a long winded first post. At the moment I am just waiting it out, without doing anything. Any ideas what it could be that caused the Nitrite to drop very rapidly,

BTW my PH is 7.8 and is buffered with a sack of agronite.

Thanks for your responses and any advice is welcome.

 

[OwduaNM]

Have you done any water changes?

 

[threnjen]

None of the above, I am sure. Day 8 is still very very early in the cycling process.

Things that could cause you to stall right now are:
* pH crash (as the bacteria eats ammoniam your pH will go down, at under 6.5 nitrification slows intensively, at 6.0 it stops)
* phosphorus depletion

The bacteria do need some phosphorous to do their thing. You can crush in a smidge of fish flake, or do a 50% water change. For the pH you can add some baking soda, or do the water change. Either thing should get you back running and you should see nitrites again.

 

[jlk]

Although ph crashes are common in a fishless cycle, I don't believe this is the case as the OP mentioned the ph being stable at 7.8 and buffered with aragonite.

I am curious about a few things though. First, as cycled media/substrate was added and your nitrites disappeared shortly after, have your nitrates increased to coincide with zero nitrite? Is your ammonia still steadily dropping (not dropping indicates a stall)?

Last, with the nitrite test, does it turn from any shade of purple to 'blue' or does it remain sea-blue (exactly like the chart) for the entire duration of the test?

 

[friendly75]

Day 9

As of this am I have not tested the water just wanted to reply to some of the above posts

-I have done no water changes
- day number 5 I gave some fish food to the tank
- when I tested for Nitirites the test drops dropped n with a swirl of blue then slooowly turned into .25 approx.
- yes Nitrate levels are almost off the chart.
Little more background... API master test is what I am using, a concern I have is that I have a kh value of 53.7 or .8 which is why I'm buffering the water. My tap water runs out much lower in lower on the low side as in 7.0. I assumed it was way to early to see nitrites in the beginning so I am not crushed but thought maybe things were going along quick.

I will post my daily am reading in a bit.

Thanks for all the help.

 

[friendly75]

Day 9 am readings

Amm- around 1ppm
Nitrites- sea blue with a tint of purple less than .25ppm
Nitrates darkest red I have seen 160ppm

I will wait for advice on what to do.

Also tank temp is set at 86f ,lights out as it's in a basement, and have two 120 volt air stones going

Let me know if u need other parameters to diagnose. Thanks again for the help.

 

[OwduaNM]

I would recommend doing a major water change in order to reduce the nitrates.

The ultimate goal to know that your cycle is complete is to see ammonia turned into nitrites then nitrates in a 24 hour period. You will not be able to see that with your nitrates off the chart.

 

[threnjen]

I would recommend doing a major water change in order to reduce the nitrates.

The ultimate goal to know that your cycle is complete is to see ammonia turned into nitrites then nitrates in a 24 hour period. You will not be able to see that with your nitrates off the chart.

I see no need for this. To check cycle completion you just dose ammonia and if in 24 hours there is 0 ammonia and 0 nitrites, you are cycled. There's no need to see your nitrate levels to determine you are finished.

Op: Just wait for the current ammonia to go away, then dose it to 2ppm and check 24 hours later. Maybe you're just cycled thanks to the stuff you got from a friend.

 

[friendly75]

Thanks for the advice

I figured to just wait it out, the less changes I do to the tank the better imo. And yes BIG THANKS to a friend willing to give up the 20 lbs of substrate even if it made me scratch my head for a bit. I will know where to turn if I need any help, thanks for the quick responses.