Dr. Tim's Fishless Cycle Bundle contains everything you need to perform a quick and safe fishless cycle with the added stress relief benefits of Dr. Tim's First Defence. The fishless cycle method has quickly overthrown old school cycling methods using "sacrificial fish" and uncontrolled nutrient sources like a chunk of shrimp or fish food.  Instead, the precise dosing of ammonium chloride combined with beneficial bacteria allows you to safely cycle the aquarium without losing fish or acquiring excessive waste and unknown contaminants.

Bundle Contents 

  • Dr. Tim's One & Only: Contains active nitrifying bacteria that provide the bacterial foundation for Dr. Tim's famous "Fishless Cycle". It can also be used to safely process fish waste in new aquariums and will help jumpstart the traditional cycling process when using live fish and other nutrient sources.
  • Dr. Tim's First Defense:
  • Ammonium Chloride
  • Fishless Cycling Recipe Card

Fishless Cycle Method

Follow the instructions carefully, step by step, and day by day. Read the entire recipe card before beginning and take note of the warnings and bullet points. Results will vary from tank to tank in terms of how long it takes for your aquarium test kits to start showing results. The accuracy of your test kit and your ability to perform the testing procedure properly does play a role, so test carefully. If you need help, just reach out to our experienced customer service crew for one-on-one support. 

  • If there is any chlorine or chloramine present in the tank water, you will need to neutralize this with a water-conditioner such as Dr. Tim's First Defense PRIOR TO ADDING BACTERA. Wait 30 minutes after adding First Defense before adding Dr. Tim's One & Only.
  • Starting your tank with RO/DI water when mixing your saltwater means your tank will not contain chlorine and negate the need for using First Defense as a chlorine detoxifier. 
  • Before adding One & Only, turn on circulation and heat the water to 75° - 78°F.
  • Remove filter socks and turn off UV, skimmers, and ozonizers for at least 48 hours after adding One & Only bacteria.
  • If you are using a live sand product such as Caribsea Arag-Alive or Ocean Direct Sand, wait 24 hours before starting the fishless cycle and test for ammonia before adding ammonium chloride on Day #1. The live sand may introduce some extra ammonia into the water and you simply need to reduce your initial dose to account for that extra ammonia.

Day 1: Add One & Only and Ammonium Chloride. Shake the bottle well for a few seconds and then pour the One and Only into your tank, sump, or filter. The water may become cloudy but don't worry, this will clear up within 24-48 hours. After the bacteria has been added, add the ammonium chloride to the tank, sump, or filter as well. 

  • Add the entire bottle of Dr. Tim's One and Only.
  • Add 4 Drops of ammonium chloride per gallon of aquarium water. Ammonia concentration should be at 2.0ppm and no higher than 5.0 ppm at any time during the cycle. Test ammonia often to get the hang of the testing process.

Day 2: Test for ammonia and nitrite and record values. We recommend using a logbook or spreadsheet and be sure to include the date and day of the week with your entry. You will find it handy for reference through the process in order to identify the rise and fall of ammonia, nitrate, and phosphate. 

Day 3: Test for ammonia and nitrite and record values into a logbook or spreadsheet. If ammonia or nitrite values are under 5 ppm, add an additional 4 drops of ammonium chloride per gallon of aquarium water. If ammonia or nitrite readings are over 5 ppm, do not add any more ammonia, you have already added enough.

Day 4: Test for ammonia and nitrite and record values.

Day 5: Test for ammonia and nitrite and record values.

Day 6: Day 3: Test for ammonia and nitrite and record values. If ammonia or nitrite values are under 5 ppm, add an additional 4 drops of ammonium chloride per gallon of aquarium water. If ammonia or nitrite readings are over 5 ppm, do not add any more ammonia, you have already added enough.

Day 7: Test for ammonia and nitrite and record values.

Day 8: Test for ammonia and nitrite and record values.

In most cases, the ammonia and nitrite will be zero after 7 days have passed or at least test below 0.5 ppm. If that is the case, Congratulations - your tank is on its way to being cycled! 

In order to test your tank for an effective cycle, you can add an additional 2.0 ppm of ammonia (4 drops per gallon) into the tank after Day 7/8.  Wait 24 hours and your tank should reduce that concentration to below 0.2 ppm.  If your tank can process 2.0 ppm of ammonia in 24 hours, it is safe to start adding fish.  If for any reason you test for high nitrate levels (added too much ammonia initially), do a water change before adding fish in order to not start out with elevated nitrates.

When stocking your tank, always go slow, adding no more than 2-3 fish at one time, and never add fish back to back. You want to give the tank time in between new additions to accommodate the new waste being introduced, this simply takes time.  Give at least 2 weeks in between fish additions for the best results. 

Additional Helpful Notes on Cycling

  • Using a substrate on the bottom of the tank is recommended for the fastest cycle because bare bottom tanks may not have enough surface area for the bacteria and it takes longer for bacteria to colonize filter blocks and ceramic media.
  • When fishless cycling, reduce the calculated water volume by about 20% to account for water displaced by substrate and decorations. For example, if you have a 30-gallon tank subtract 6 gallons (20%), so calculate 24 gallons as the final water volume when adding ammonia.  >>Use our Water Volume Calculator
  • Don't overdose ammonia beyond 5 ppm; this is not helpful and may stall the cycle. If it does get this high, do water changes right away to lower the concentration and continue.
  • When adding drops hold the bottle vertically and don't press so hard that there is a steady stream of liquid. Instead, add drop by drop.
  • Some conversions for larger tanks: 1 tsp = 5 ml = 100 drops, or 1 Tbsp = 15 ml = 300 drops.
  • If you are using a live sand product, wait 24 hours after setting up the tank and running the filter before adding ammonia drops. Test ammonia levels prior to adding ammonium chloride as the live sand product may introduce some ammonia and you may need to reduce or eliminate the addition of ammonium chloride. Remember, never higher than 5 ppm ammonia.
  • BE PATIENT - every tank is different in terms of the exact time frame.
  • You DO NOT need to add ammonia every day, this will only result in skyrocketing your nitrate levels or stalling the cycle altogether.
  • In many cases you will not see nitrite - that is because the product is working rapidly.
  • In some cases you will not see nitrate - this is because some test kits do not measure nitrate well when the concentration is less than 20 ppm. Nitrate will not be 20 ppm or higher for several weeks (or several ammonia additions) so don't worry about this.