Weekly maintenance. How much is too much?

I have a small 16 gallon nano tank. I use RO/DI water only. Every week i do maintenance of the tank in this order:

- prepare 5g of fresh RO/DI water, mix salt in it and heat it to 25 degrees/Celsius (298K),

- clean rocks lightly with a brush to remove debris and Hermit crab poo, sometimes i celan harder to remove algae more,

- take out all electrical equipment (for easier cleaning of the tank), scrub it with brush,

- clean glass all around,

- siphon the sand,

- replace missing water with 5g of fresh one,

- clean the glass from the outside,

- done.



Is this too much, not enough, should i do it differently?



Tank is doing ok, corals look happy, fishes too, but i have algae problem, specialy red hairy ones on the rocks and sand. I feed once a day.



- 1 Yellow clown goby,

- 2 Firefishes,

- 1 Peppermint shrimp,

- 3 Nassarius snails,

- 2 blue leg Hermit Crabs.



Tests show 0 Nitrates and 0 Phosphates. Shouls i use any other test if RO/DI water is good or any other test for aquarium water?



Tank is 6 months old.