Fishyfanatic
Aquarium Advice Addict
You keep asking the same question over and over and it has already been answered. The percentage that you change is based on how high your levels are. If you have 5 Nitrites, then by doing a 50% water change, you are lowering it to 2.5. Don't do more than that at once though. This is why having a good test kit is important. The test strips are far more expensive than the Master Test Kits are. I figured it up one day and the strips were something like 800% more expensive than the liquid reagent kits. Try www.bigalsonline.com and look for the AP Freshwater Master Test Kit. It's about $20 after shipping. That will give you 700 tests. The test strips are somewhere around $15 for 20 strips.