Test before and it will give you an idea of how well your filter bacteria are working. Make a note of the results and the date/time. If you also test a few hours afterwards and note down the results, you will have an idea of what impact that water change had on the tank environment (i.e. how much of the ammonia/nitrite/nitrates it removed).
It's a difficult situation to be in when you have fish in an uncycled tank - you get caught in a bit of a catch 22 situation to be honest. We know that if you have a lot of fish in an uncycled tank there will no doubt be levels of ammonia present, which is harmful (deadly) to the fish, so we try to remove the ammonia through water changes.
But, in order for a filter to cycle properly it needs...ammonia - so removing it all doesn't give the bacteria much of an opportunity to grow. It feeds off ammonia so removing it's food source will starve the colony. You end up getting nowhere fast, unfortunately, and it is a slow, long-winded process to reach the stage where the filter has enough supply of bacteria to handle the bioload in the tank.
It's just a case of being very patient and stringent with your tank maintenance and testing for now.
Regards - Athena
It's a difficult situation to be in when you have fish in an uncycled tank - you get caught in a bit of a catch 22 situation to be honest. We know that if you have a lot of fish in an uncycled tank there will no doubt be levels of ammonia present, which is harmful (deadly) to the fish, so we try to remove the ammonia through water changes.
But, in order for a filter to cycle properly it needs...ammonia - so removing it all doesn't give the bacteria much of an opportunity to grow. It feeds off ammonia so removing it's food source will starve the colony. You end up getting nowhere fast, unfortunately, and it is a slow, long-winded process to reach the stage where the filter has enough supply of bacteria to handle the bioload in the tank.
It's just a case of being very patient and stringent with your tank maintenance and testing for now.
Regards - Athena