I have a DIY filter with 16 litters of siporax and bio rio.
I clean the sand every 2-3 days.
Only 16 litters.your filter is only 16 liters?? thats less than 5 gallons on a 240 gallon tank....you dont have water quality problems? I may be misunderstanding and you mean that you have 16 liters of actual filter media.....