7 month old tank - brown slime algae

[MF_Lon]

Thank you, I've updated the lights to come one two blocks now and reduced the total time. I'll do a tidy up of leaves, don't think there are too many dying, all leaves are in fairly good health albeit the brown algae.

Will keep an eye out on the dropping hardness, won't be doing huge water changes when I introduce RO probably just 10% a week at that stage.

[plankton]

Welcome to the forum.
Also make sure that the water flow around the tank gets everywhere.
Hydrogen peroxide (spot-dosed onto the slime) will kill any spores etc, but I think it may be difficult to get hold of any at the moment.
RO will need to done very slowly so the fish can readjust, over months probably, building up the percentage week by week.

[arthurfarris]

Steps to Clean Old Aquarium Gravel: Step one is the standard cleaning solution: about 10% bleach and 90% hot or warm water, or you can use a lower concentration of bleach to be safe for fish after that. The second step is to put the fish gravel in the pot plus the bleach solution, pour the water to cover the gravel. Soak the gravel for no more than a quarter of an hour, during which time you can stir to irritate the cleaning solution. The fourth step is to rinse the aquarium gravel and then dry it. Finally, return it to the aquarium.

[fr499y]

If bleaching anything always follow with a soak in treated water ( prime or safe works best ) before returning to tank.