Effectiveness of circulation and volume of filtration are certainly things we all persue to potentially lower the burden of maintenance but unfortunately in a practical sense they often have their limitations. The weekly substrate-clean-water-change is really more powerful in many ways, even though it is labor intensive of course and is the habit most of us slip away from I think. It is just a huge deal siphoning lots of debris totally out of your system - having a positive cascade of effects on everything. Each tank is unique, some able to go longer, but in general as we allow our habit to slip (from each weekend to every other weekend, then from every other weekend to every third weekend, then "oh my gosh it's been a month"...that sort of thing) we eventually see why we ever had this maintenance need in the first place.
Filter maintenance also plays a role. The normal habit of monitoring NO3 creep to establish your filter box cleaning interval will usually easily take care of ensuring that debris will not max out in the filter, but with large cannisters that can go a long time, it can become easy to also let that time interval slip! Eventually this catches up with you.
~~waterdrop~~
How long do you leave the lights on in the tank? It may be a simple case of reduce the daylight hours to prevent algae growth.
