Should I do a water change? (day 3 of cycle)

[Jed Fish]

My 70L tank has been cycling with 6 neon tetras for 3 days, on the first day, ammonia was at 0.25ppm, second day 0ppm and third day 0ppm. Nitrites are at 0ppm, and nitrates on the second day were 3ppm. I changed the water the day before yesterday. Should I do a 20% water change, or not? Because my ammonia is low so I dont want the benificial bacteria to starve. Or should I only change the water when ammonia levels are more than 1ppm?

 

[BBradbury]

Jed...

Cycling a tank with fish takes enough fish to produce a steady source of ammonia. That means 3 to 4 hardy, decently sized fish for every 10 gallons of water. 6 tiny fish in roughly 20 gallons of water isn't enough. I would add 6 more small fish and a lot of Hornwort. Then, test the water daily for ammonia and nitrite. When you have a positive test for either, remove 25 percent of the tank water and replace it with pure, treated tap water. Just test and change the water when needed. When several daily tests show no traces of the above toxins, the tank is cycled.

B