the python works well for a lot of people. However how many people that answer this thread even know what there measured chlorine / chloramines levels are if they are on city water?
I got lucky for 2 years until I moved.
My water comes from filtered river water, rains and snow affect tap water quality, esp.: nitrates....construction in the area? The city will increase the disinfectant level? How much prime do you need? directions on cap will only lower water level to a certain degree...as we know prime does not remove Ammonia it only converts it to a non toxic form where your bio filter will clean it up. So a lot of you are gambling by dosing on entire tank volume first and then directly filling from the tap..how many PPM of chloramine does your tap water have? Nitrates? Nitrites? AMM? Lead? Arsenic? Flouride? My tap is sometimes around 20 PPM of Nitrate , one the chemical by products we are trying to remove by water changes
Stunted , shortened lifes are the after effect of bad water .. Take it from me , the prime didn't immediately take care of my tank, the city increased their chemicals in the water that day. Causing by bio bed to dies off .
Needless to say it's safer to buy a Rubbermaid brute and let your treated water sit for 24 hours. Then take a small pump to refill your tank with SAFE aged water.
from Seachem:
Use 1 capful (5 mL) for each 200 L (50 gallons*) of new water. This removes approximately 1 mg/L ammonia, 4 mg/L chloramine, or 5 mg/L chlorine.
