I just use a 100gpd unit and shut off when the holding tank is full. I added another membrane to one unit to double production.
If one changes about 25% of water daily and has a 4x2x2 feet aquarium how much capacity output reverse osmosis filter will be a better buy and comfortable to use. The RO systems come with output of 25L per hour to 50L to 100L per hour and tap water in my area is about 350 tds.
I just use a 100gpd unit and shut off when the holding tank is full. I added another membrane to one unit to double production.
A 4X2X2 tank is 120 gallons (~455 liters). How much R/O capacity you need depends on how long you want to wait to produce R/O water. To me, it'd be simpler to get a large storage tank and produce enough to use over multiple water changes.
At my age, everything is irritating.
Thanks for the reply