I always just added SeaChem Prime of Amquel or an equivalent in Sweden to the water right prior to refilling the tank.

I just make sure the temp is slightly cooler than the tank water.
Add the dechorinator(the types that handles Choramines) and that's it.

If you are interested, you can add a carbon filter right by the refill location, or for the whole house or drinking water, shower etc.

That will remove that and organics, and give a better flavor to the water.

Go in attack that algae good, drop the light down some, add SeaChem Excel if you can get a hold of it there. Add a bit more CO2, trim and attack the algae.


Regards,
Tom Barr