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Simplified Fishless Cycling Instructions

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Fish Aficionado
Oct 28, 2006
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Kent, UK
So the main sticky for Fishless cycling is great but it suffers a little from information overload and that makes it hard for some to follow the instructions. I thought I would have a go at a "condensed" version. This is in no way meant to replace the original instructions but just act as a quick reference in addition to them.

Quick Reference - Fishless Cycle
First you should fully read the link below. This explains in detail why we need to do a fishless cycle and how. These instructions are meant as a quick reference and supplement to the original thread.

Original Fishless Cycle Thread

Day 1 – Dose Ammonia to 3ppm. Use https://fishforums.net/aquarium-calculator.htm to work out how much Ammonia to use. After 30 minutes, test the tank water for Ammonia to make sure it is around the 3ppm range. Make a note of how much Ammonia you used. Now wait 2 more days before starting "Stage 1 - Firsts Tests".

Stage 1 - First tests Test Ammonia and Nitrite every 3 days.
Is ammonia under 0.75 ppm and Nitrite over 2ppm?
If No repeat this step in 3 days.
If Yes Add the same amount of Ammonia as you added on Day 1 and go to “Stage 2 – Snack Dose”.

Stage 2 - Testing for “Snack Dose”,
Test Ammonia every 2 days – You are now looking for Ammonia to go to zero. When Ammonia has been zero for 2 tests in a row (4 days with 2 tests) you need to add a “snack dose”. This is 1/3rd of your original dose. You only need to do this “snack dose” now, once you have done it go on to “Stage 3 - Daily Testing”.

Stage 3 - Daily Testing – Test Ammonia and Nitrite.
Is Ammonia Under 0.25ppm and Nitrite Under 1ppm – If Yes, add full Ammonia dose and continue daily testing. You may have to do this a few times.
Is Ammonia and Nitrite Zero – If Yes, Your cycle is finished. Do a large water change and you can now add fish.
If Ammonia and Nitrite read anything else wait and repeat this step every day.
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