New 55 Gallon Tank - Deciding btw fish-in vs fishless cycling.

[AnxiousVentures]

We set up a new 55 gallon tank yesterday. The water is dechlorinated and has been "cycling" (I don't know what other word to use here) since yesterday, so just about 30 hours at this point.

I've familiarized myself with the two methods of cycling and having a hard time deciding between the two.

We currently have an "established" tank, but it is consistently high ammonia that cannot be brought down and we are starting over with a fresh tank.

I can easily transfer a few fish and decor + live plants from our 30 gallon to our 55 gallon, or I can cycle this new tank with pure ammonium chloride.

I guess I'm looking for opinions and experiences with both, as I am a first-time "proper" cycler.

I also have a question I can't seem to find an answer to: Would it be safe to transfer over the filter media from my current 30 gallon tank, given the high ammonia content, or will the filter media bring ammonia with it?

 

[Aiken Drum]

To cycle a tank you need to grow denitrifying bacteria to consume ammonia and nitrite that your tank produces. The bacteria needs an ammonia source to grow colonies sufficient in size to consume all the ammonia and resultant nitrite and turn it into nitrate which typically you remove through your regular water changes.

Two commonly used methods to cycle a tank are called a “fish in” cycle and a “fishless” cycle.

A fish in cycle uses fish waste as an ammonia source and regular water changes are undertaken to ensure that water parameters are maintained at relatively non toxic levels. This has been the go to method to cycle a tank for many years, and it commonly is the way new fish keepers cycle a tank when they have bought fish with no knowledge that a tank needs cycling and how to go about it.

Pros.
You get to keep “some” fish pretty much on day 1 of setting up your tank.
More consistently gets you through your cycle.
Only real choice if you already have fish.
If done simply, eg stock lightly, add fish slowly, you can fishless cycle safely without testing. Although testing your water while cycling is still a good idea.

Cons.
Lots of water changes, especially if you are doing a fish in cycle with a fully stocked tank.
Although you should be doing plenty of water changes to maintain relatively safe water, your fish will be living in waste which isn’t ideal.
Can take a long time (several months) to go from an empty tank to fully stocked if done safely.

A fishless cycle uses an ammonia source to replicate the fish waste that a tank of fish would produce. This ammonia source can be pure ammonia, an aquarium specific ammonium chloride product like Dr Tims Ammonium Chloride, a cocktail shrimp or fish food.

Pros.
You cycle the tank before adding fish, therefore they shouldn’t be exposed to their own waste.
No need for regular water changes while your tank cycles.
Can be quicker to go from an empty tank to fully stocked.

Cons.
Needs patience, you will be looking at an empty tank for several weeks.
More technical approach requiring dosing ammonia and will need to be done alongside regular testing.
Less consistently successful than fish in cycles, especially with new fish keepers who don’t understand the process and expect it to run to a timetable.

 

[Aiken Drum]

My opinion.

I prefer fishless cycle. I trust the process, know how it works, understand how long it takes etc.

But, i know that people more consistently get the results they desire (ie fish swimming around without dying) going fish in cycle "done properly". When trying to do fishless cycles people often dont understand how it works, get frustrated with a lack of progress etc, and sometimes give up entirely with the hobby without ever buying a fish.

Whichever way you go, if possible, have both tanks running. Either fully cycle your new tank before moving all the fish in 1 go, or if you do a fish in cycle, gradually move fish from one to the other in a controlled manner over an extended period of a few months.

Either way i wouldnt move filter media from one essentially uncycled tank to another uncycled tank. There isnt much benefit in your case and you would be removing what little beneficial bacteria you have from the tank with all the fish in it. If your old tank was cycled it would be a very different conversation.

 

[AnxiousVentures]

My opinion.

I prefer fishless cycle. I trust the process, know how it works, understand how long it takes etc.

But, i know that people more consistently get the results they desire (ie fish swimming around without dying) going fish in cycle "done properly". When trying to do fishless cycles people often dont understand how it works, get frustrated with a lack of progress etc, and sometimes give up entirely with the hobby without ever buying a fish.

Whichever way you go, if possible, have both tanks running. Either fully cycle your new tank before moving all the fish in 1 go, or if you do a fish in cycle, gradually move fish from one to the other in a controlled manner over an extended period of a few months.

Either way i wouldnt move filter media from one essentially uncycled tank to another uncycled tank. There isnt much benefit in your case and you would be removing what little beneficial bacteria you have from the tank with all the fish in it. If your old tank was cycled it would be a very different conversation.

This is my thought. I decided to go fishless, as it seems to be more clear-cut for my brain. Although, I can't get away from my confusion around where the beneficial bacteria come from based on a new tank with new substrate and new rocks. It almost feels magical, haha. Where does the bacteria that eats the ammonia come from?? What a strange concept - but I get and I know it is very solid chemistry. It's been a while since I took chemistry, though!

 

[Aiken Drum]

Ill post a fishless cycle process. Im not sure if i gave you one previously or if you picked up on it from another post.

As part of that process there are a couple of options for artificially introducing that bacteria into your tank. But, if you dont do this artificially it will still cycle. Ive seen different opinions on where this bacteria comes from initially. Some people say its in the general environment and enters from the atmosphere, some people say its in your tapwater and whatever water treatment you have isnt able to kill it off 100%. My opinion is its from the general environment. Either way once that bacteria finds a food source in ammonia in your tank it will grow and establish in your tank.

 

[Aiken Drum]

To cycle a tank you need to grow denitrifying bacteria to consume ammonia and nitrite that your tank produces. The bacteria needs an ammonia source to grow colonies sufficient in size to consume all the ammonia and resultant nitrite and turn it into nitrate which typically you remove through your regular water changes.

A fishless cycle uses an ammonia source to replicate the fish waste that a tank of fish would produce. This ammonia source can be pure ammonia, an aquarium specific ammonium chloride product like Dr Tims Ammonium Chloride, a cocktail shrimp or fish food.

Ill assume we are using an ammonium chloride product.

Set up your tank. Make sure everything is running smoothly. Make sure you have used a water conditioner product with any tap water you have put in your tank. If you have an adjustable heater raise the temperature to 28c/82.5f.

You should have a test kit. Preferably a liquid test kit. It should test for ammonia, nitrite, and nitrate.

Dose the ammonia chloride to approx 4ppm and start testing daily for ammonia. Once your ammonia drops below 1ppm redose it back to 2ppm. This may take a couple of weeks.

Start to test daily for ammonia, nitrite and nitrate. Whenever your ammonia drops below 1ppm redose it back to 2ppm.

You should start to see nitrite and possibly nitrate in your daily tests. Over time your nitrite should start to rise and the amount of ammonia should start to drop further. Your ammonia may start to not be detectable in your daily tests. Keep redosing ammonia daily if you see it below 1ppm. Your nitrite may rise off the testing chart. I prefer to keep nitrite within measurable levels so it shouldn’t hurt to do a water change to keep readings on the chart. Remember to add water conditioner whenever you put tap water in the tank. Nitrate should appear in your water test at some point too.

Over time your nitrite should level off and begin to fall in a similar manner to what your ammonia tests did. When you are able to dose ammonia to 2ppm and 24 hours later see 0 ammonia and nitrite you are cycled. At this point you have enough denitrifying bacteria to consume all the ammonia and nitrite of a moderately stocked tank. You may want to continue dosing ammonia for a few days to make sure it continues to consume all the ammonia and nitrite and be sure your cycle has properly established before proceeding.

Your nitrate will likely be very high. Do a big water change to get nitrate down. Preferably below 10ppm. Adjust your temperature to the needs of your fish. Get your fish, acclimate and add to your tank. I would advise stocking lightly to start with and slowly adding fish until fully stocked.

A fishless cycle typically takes 6 to 8 weeks.

A good way to speed up this process would be to put a small amount of filter media from an established filter into your filter, or get a sponge from an established filter and squeeze it into your tank water. Perhaps you have a friend who keeps fish who could let you have some? This will seed your filter with the bacteria you are trying to grow and speed up the process.

Another option is bottled bacteria like Dr Tims One + Only or Tetra Safestart. These products wont instantly cycle a tank as they claim but in a similar manner to adding established filter media they can seed your filter with the bacteria you are trying to grow to establish your cycle. These products are hit and miss as to whether they work at all, but are an option if established filter media isnt obtainable and may speed up the process from several months to several weeks.