What are you treating?
Doxycycline wipes out filter bacteria and should only be used on known bacterial infections that haven't responded to normal treatments.
Antibiotics work best in bare tanks with no filter, gravel, wood or porous items. It's a good idea to wipe the inside of the tank/ container down and change all the water between uses with any antibiotic so they can work more effectively on treating the fish rather than killing bacteria in the tank and filter.
If you are treating a display tank, wipe the glass down, clean the filter, do a complete gravel clean and massive water change before treating and between treatments so the tank is cleaner and the medication can work more effectively.
Increase aeration/ surface turbulence when using any medication in an aquarium.
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To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.
or use the aquarium calculator at the following link.
When you measure the height, measure from the top of the substrate to the top of the water level.
If you have big rocks or driftwood in the tank, remove these before measuring the height of the water level so you get a more accurate water volume.
You can use a permanent marker to draw a line on the tank at the water level and put down how many litres/ gallons are in the tank at that level.
Remove carbon from the filter before treating with chemicals or it will adsorb the medication and stop it working. You do not need to remove the carbon if you use salt.
