My problem with fish-in cycle

[Rpvance]

I have had a light stock of fish in my new tank since Jan 1st (yes, 46 days) and have NOT seen nitrites yet.

I averaged a 20% water change almost every day for the first month regardless of the ammonia readings. They never reached over .25. Now looking back I think many times it may have only been a trace of ammonia (it was actually hard for me to distinguish if the api test read all yellow, or partly green...then i started testing my tap water next to it). I read that water changes WOULD NOT slow the cycle so I figured it could only be a good thing.

Over the last week and a half I have changed my strategy, still monitoring closely but have made maybe 3 pwc of 20% - almost hoping for the ammonia to be high so that I can get the cycle over with and add some darn fish! It still hasn't gotten close to .5 And still no nitrites. I thought nitrites were supposed to come shortly after adding fish, some things I have read say around THREE DAYS after!!

1)Should I let my ammonia get higher before I make pwc changes? Like above .25, but less than .5?

2)Should I vacuum up waste in the gravel during the cycle?? Or since I do this could it be slowing it down by sucking up bacteria and its food? (I thought this was proper maintenance)

3)If it has taken this long and I havent seen nitrites, how long could the cycle completion take?

It seems to me that this is the whole problem/point that fishless cycling advocates are trying to make, and maybe I am just slow....but basically the fish HAVE to go through some toxic levels during the process, no matter how much you care and want to do the perfectly humane thing. It might be worth mentioning to newcomers - so much of the advice out there talks about changing water,changing water,monitoring levels, changing water -- when the reality is it means "letting" your tank cycle.

What does everyone think?

 

[jetajockey]

Hi. I think there's a few misconceptions that often get thrown around lightly. The first one is that water changes don't slow a cycle down. Granted, the nitrifying bacteria colony is largely non-motile, as in it doesn't float in the water column but rather adheres to surfaces via biofilm. This is true, but water is the medium that it gets oxygen and food from. Doing water changes kills bacteria that is on tank walls (tank walls dry out), as well as in some cases adds a new parameter of water into the tank so that things are unsettled. Water straight from the tap tends to have a different pH and whatnot, this could in theory slow things down, but probably not any significant amount. Both of those are valid reasons that could mess with the cycling process, but they are generally overlooked or passed off, mostly because the benefit of the addition of new water outweighs any potential negatives brought on by it.


The other misconception often passed around is that if you let your ammonia get over .25 that your fish are being exposed to toxic levels of ammonia. This is untrue in most cases, but the toxicity of ammonia is totally dependent on the tank pH and temperature. There is a chart on ammonia toxicity somewhere.

To answer your questions:

1)Should I let my ammonia get higher before I make pwc changes? Like above .25, but less than .5?

2)Should I vacuum up waste in the gravel during the cycle?? Or since I do this could it be slowing it down by sucking up bacteria and its food? (I thought this was proper maintenance)

3)If it has taken this long and I havent seen nitrites, how long could the cycle completion take?

1) It's probably not going to hurt anything if you do, you could double check the toxicity level of that concentration against your ph/temp though to make sure. The other things to think about is that color shade testing is not an exact science, it's more of a guesstimation, so I wouldn't hang on the numbers with any rigidity personally. Also, if you dose with Prime in between water changes, then you could easily cut back to every-other day water changes since Prime detoxifies ammonia for up to a 48 hour period anyhow, so either we trust the product to do as claimed or we don't. (A little different than the massive daily water changes some will claim about fish-in cycling eh? )

2) I wouldn't unless there is an absolute mess in there, it's best to leave things alone as much as possible while the tank is getting established. Another misconception often thrown around is that there is little to no bacteria in the substrate bed.

3) The nitrite => nitrate portion in a fish-in cycle can sometimes go silent because the buildup is very gradual. It's still hard to predict how much longer you have since there are so many factors involved. The reason why you'll see so many fishless cycling threads freaking out about a super nitrite spike is because they are dosing a massive amount of ammonia to begin with, even your average fully stocked fish-in cycling tank is not going to produce numbers like that on a daily basis.

 

[Supra]

I did fish in cycle on my first tank and I never saw nitrites. Everything is good and fish are happy. You are probably cycled
Supra

 

[Rpvance]

Thanks for the replies!

It's my understanding that ammonia levels should be zero (without the introduction of new fish) for my tank to be fully cycled.

Another question, about using Prime to condition the water - it "detoxifies" ammonia, does that affect the cycle time negatively in any way? I mean, is that ammonia still processed by bacteria?

 

[jetajockey]

That's correct. I've had some setups lag on for months with trace ammonia readings, whether it is faulty testing or if there truly was a trace amount in there, all was well and I monitored it regularly to make sure it never got out of control.

They claim that NH3 (Ammonia) is temporarily converted to NH4(ammonium) so it's still available for the biofilter but toxicity is minimal.

 

[Mab2000]

Could it be with the light stocking and frequent water changes there isn't enough bioload to make the bacteria thrive?

 

[HeatherW]

RP - I am doing a fish in cycle on my 20 gallon. I go more by the chart that jetajockey mentions. also, my tap water has ammonia in it so changing the water all the time is not really going to lower my ammonia - it is in the tap. instead I use that as a guide and try not to let it go too much over the tap reading (+.25 over tap). also i use the prime neutralizing effects to my advantage. if it has been several days since the last water change and the ammonia hasn't moved I still do a water change just to "freshen" up the water. IMO you do need some ammonia in your tank for your BB to eat

hope all this helps!

 

[Rpvance]

Ive cut back on the water changes to help. Still monitoring and testing daily.

Fish stock could be an issue...5 neon tetras and a gourami in a 26 gallon I thought would more than enough?

 

[HeatherW]

Ive cut back on the water changes to help. Still monitoring and testing daily.

Fish stock could be an issue...5 neon tetras and a gourami in a 26 gallon I thought would more than enough?

i am not an expert on stocking so I can't help you there. my 20gallon is possibly overstocked because I have a molly in there and she keeps having babies!!!

yes - keep monitoring daily, but then use your judgement on the water changes. sometimes I see trace amounts of the nitrites and then I end up doing a WC and then they are gone again. they are in there. just make sure you check your nitrAtes at least weekly as well. that will let you know for sure when you are cycled (unless maybe if you have plants) in any case eventually all the ammonia will go away. I cycled my 5 gallon with fish in as well. I honestly thought it would never cycle since it is such a small tank and then one day I saw trace nitrites and then the next and then a little more, and then a bunch!! did some big water changes and before you know it my tank is finally cycled. so i know it will work - just may take some time.

 

[Rpvance]

Thanks for the advice everyone! Just to update:

I went on vacation and when I came back 3 days later, BAM, Nitrites levels were high. After 1 week of careful testing and water changing to keep the Nitrites around .25 they were gone! Showing zero on ammonia and nitrites....and....Nitrates are here! Tank cycled!