I will just add to a couple points already mentioned. First is the placement of the filter intake and outflow. There is considerable advantage to having these at opposite ends of an aquarium, and a 4-foot or larger length tank should always have this positioning, It is the only way to achieve a fairly even water movement throughout the tank. The filter return (spigot or spray bar) should be near the surface at one end, and the filter outflow closer to the substrate at the opposite end length wise. About 5 inches off the substrate should work fine.
As for screening, several options have been suggested. Another is a fish net, one of the small ones; you can cut the mesh off the net frame and place it over the filter outflow, secured with a bit of fine wire. One disadvantage to any method is that larger debris will not get pulled into the filter, but this is not really problematic.
Rinsing (= cleaning) the media depends upon the tank. The water must be able to flow fairly unrestricted (the more detritus collecting, the slower the flow will be). However, some build-up of mulm is advantageous, and this is another excellent source of CO2 from the breakdown of organics. I now tend to rinse my canisters every 3 or 4 months; one tank needs 3 max, the other two 4-5. I rinse them under the tap, and have done for over 20 years. In planted tanks the nitrifying bacteria is not an issue to fuss over.
Algae and phosphates is still generally mis-understood. Phosphorus/phosphate is an essential plant nutrient. Algae will make use of it (if the plants cannot for reasons of imbalance with other nutrients and light) at levels above 0.02 ppm. Diana Walstad writes of phosphate levels in her tanks running between 1 and 5 mg/l (ppm) which is "high" in one sense, yet she has no algae issues. It is not a nutrient that needs to be specifically added, since all fish foods contain sufficient. But I would suggest that algae problems are not tied to phosphate but more likely to an imbalance involving several nutrients and light. I've no idea what the phosphate level is in my tanks, but I would never use any product to remove/reduce this. As I so often write, finding a natural balance with the least amount of intervention by the aquarist (using chemicals, substances, etc) will always be easier in the long run and safer as it is more likely to be "natural" and thus consistant.
Byron.