I have the same DE filter plumbed with the "matching" 1.5 HP pump and it have plenty of flow... maybe too much for my 21 Round.
I would like to have a two speed to be able to run it longer with less flow to improve skimming but as it is now, I only need to filter for an hour or two per day during the normal season. I am considering adding a Pool Skim to improve skimming and allow skimming while the Aquabug is cleaning the floor (since it disables the skimmer when in use)
Just saw your "bump" question. It is exceedingly effective as saving your DE. Since I have had the pool (about 9 years) I have only had this filter and it works GREAT! when the pool is being maintained. If I let it get green, it requires some extra attention. What I mean is, with a sand filter, you run the pump for several hours (24/7?) and it eventually gets most of the debris out of the water (low effort/low cost/long time to clear), you never need to replace the filter media/sand. A cartridge, will filter almost as well as DE but the media/filter needs to be replaced at significant cost (some a several hundred $$ each and have multiple filters) (faster and better than sand, can be fast or slow dependent on media quality, cost can be high is need new media).
When I have a bunch of junk in the pool, I can only run the filter for an hour or two and then I need to "bump" the DE. Then I can filter for another 2 hours. I repeat this process until the pool is crystal clear or the filter plugs up in 30 minutes or less. I can "bump along" for a month or two. When the filter pressure rises above 20 PSI, in less than 30 minutes of run time, the filter media (DE or cellulose) needs to be changed. I open my filter and change the media and rinse the "fingers" in about 30 minutes. The new DE/Cellulose media is less than $5 each time I change it. When the pool is clean and maintained correctly, the filter will last about a month or two (with bumping) depending on how much junk floats in and how many people use the pool. I have a large debris load from the crepe myrtle blooms, lots of kids, floating bugs (honey bees) and the dog. I change the media once or twice a summer (May-October) after I get things straightened out at the beginning of the season.