As a newbie, I'm wondering if the gurus could help me understand how to get good energy efficiency while maintaining a well-filtered pool? What I'm really asking about is the resistance caused by different kinds of filters (cartridge, sand, D.E.).
Mine is a 14,000 gallon pool with salt water chlorine generator, and Pentair Intelliflo pump (which has quirks, but I like from an energy efficiency standpoint). Currently, I have a Hayward Stay Clear Plus cartridge filter with a 120 sq. ft. cartridge. I've set the Intelliflo to do one turn per day, and to take about 10 hours to do so. This works out to about 23GPM, apparently.
The pump tells me it is using about 250 watts of electricity when the filter is clean. However, after a few days, that energy usage climbs to about 650 watts. At this point, I've been cleaning the filter, and the enercy usage drops back to 250w. Obviously, this is too often for cleaning (it is becoming annoying), and my water looks nice and clean so I'm not sure where the dirt is all coming from. However, when I clean the filter, lots of dirt comes out, so perhaps it's not as clean as I think it is. Or perhaps what I think of as "dirty" is really just "not quite clean" (the filter is beige before cleaning, white afterward, and during cleaning a fair bit of what looks like fine garden dirt comes out).
Anyway, from reading this forum, I know about the filtering efficiency of cartridge, sand, and DE filters (ie: how small the particles are that they can filter - although why this is called "efficiency" I don't know). But what I haven't found discussed, is the energy efficiency of these filters, in terms of the resistance they provide to water flow. DE seems to stop the most dirt, but does that necessarily mean it provides the most resistance to the flow of water (in which case energy usage would go up to maintain the 23gpm)? Or is there a free lunch -- does the DE filter stop much more dirt while providing not much more resistance than sand or cartridge (or maybe even less)?
Bottom line is that while I of course want absolutely crystal clear water, I don't want the life-cycle cost to be a big hidden amount that is paid out over time from increased energy usage. So, for clean water with low energy usage, should I stick with cartridge, move to sand (possibly with a sprinkle of DE on top), or go with DE?
As for cleaning the cartridge so often, perhaps I just need a bigger cartridge to increase the cleaning interval? Is 120s.f. enough for a 14k gallon pool?