Luis_Gil said:
Im trying to find some easy guide how to cycle a tank, i think for a new guy its very difficult.
Because some people say for i take 25-50% water Out and put new without chlorine , everydays. Other guys say for i put some ammonia solution inside the tank.
So for me This is all very confused

It can be confusing.
The answer is simple: Let the tests tell you what to do.
Test one: ammonia.
Test two: nitrite.
If ammonia is too high - then water change to lower it.
If nitrite is too high - you have two options, either change water or add salt.
Its a bit of a logic puzzle.
If A then B. If C then D. You will understand by the end of it.
This calculator can help you.
http
/www.hamzasreef.com/Contents/Calculators/FreeAmmonia.php
The free ammonia (NH3) must stay under 0.02 mg/L. That's where the value gets toxic to the fish. BUT, the ammonia test you are using measures BOTH NH3 and NH4. And the percentage of NH3 compared to NH4 is based on pH and temperature. Use that calculator to keep an eye on the NH3 number. If its getting close to 0.02mg/L, do a water change to lower it.
For example, if you have 1ppm ammonia on the test kit, with 7.0 pH and 27 degrees Celsius, the TOXIC NH3 would only be 0.0067mg/L, which means that its not toxic. So, a water change isn't NEEDED, but doing one is ok.
As for nitrite, it can be a bit more complicated. But, let me leave it at this for now, nitrite is MORE dangerous than NH3, so if you see 1ppm nitrite, that's a cause for concern. The easy answer is to just change the water. But, even a 50% water change at 1ppm isn't enough. So, the BEST answer is to add salt. (Your fish can handle it.) Adding the salt allows the fish to stay in the water and not take the nitrite into their blood. Nitrite in their blood stops their ability to get oxygen, and they suffocate. BUT, with salt in the water, the salt stops the nitrite from getting into their blood and the fish can survive in the tank without a problem.
When you reach that point, we'll cross that bridge. In the meantime, relax, enjoy your fish and get ready for some water changes.
