This is the third Amazon review I've written in over 20 years, since I joined at just about the start of this site. But, I only speak if it's important. My two other reviews are on books. Nothing else - until now. Equipment is usually underwhelming. Especially these days, when nearly everything is junk. This ingenious device is a notable exception, and no surprise it's patented. My pool is new, large, high-end, concrete & traditional plaster. Good water chemistry, Pentair top-end filter, crystal-clear water, but because of extreme tropical sunshine, high temperature (warm air + lots of gas pool heater use), and lower than typical chlorine use due to sensitivity, occasional algae growth (confined almost exclusively to the walls) does occur. I grew-up with a pool and learned to sweep & clean it as a child. Chores. Daily, for many years. Pool care is second-nature to me, I know all the secrets better than pros, and I have never seen a design make such great use of the physics of water motion as this brush (I also spent a lot of time on boats). Just as the manufacturer and other reviewers opine, the huge drag created by the top-fin - as this thing moves - exerts massive downward pressure that drives the bristles hard against the plaster surface, scrubbing away all the algae from the porous plaster in a way no amount of human strength can do on its own. It then flips down like a dream on your upstroke, slicing back up through the water with slick perfection. Kind of reminds me of my rowing days. Vertical walls I could not get an angle on with a regular brush were finally clean in minutes, and while I use high arm strength to sweep no matter what the tool (one reason I hate tennis & golf - all the ball travel is in the racket/club/ball technology & in your form - unlike real sports, where your actual strength determines force, ergo, distance), it's easy to see this brush would increase even a weak arm's thrust, as advertised. It's all in the physics, and it works. My only warning is to choose the right seting for the fin on top, which (in my opinion) is one notch away from the maximum pressure setting. The more the fin sticks out, the more pressure it gives, but the final notch causes the fin to flip-over too much as it goes almost perpendicular to the pole, so don't waste your time on that setting. The lower settings (presumably for weaker arms) don't clean as well, defeating the purpose of the brush, so use the 2nd highest setting. You can also use this on the pool steps (if they're long steps, works better, larger pool), and it creates the same downdraft, increasing cleaning power. I use it on the pool bottom as well, and if you keep your angle shallow, same effect. It's a fantastic overall pool brush. Nothing better. I still have to use a curved edge brush for tight spots around the steps, and a very small steel bristle brush for other step hard-spots and other areas where algae is indurate (plaster rough spots), but besides that, this is my main go-to brush now, and I never heard of it until a few weeks ago. Last comment is that almost all injection molded plastics these days are made in China, so I find it hard to believe this is made in the USA even though the ad says so (didn't I see "designed in USA, made in China" - like iPhones...once it arrived?). I can't remember, and I'm not going to go check the pool right now at a cafe, but if it truly is made in USA, that's icing on the cake. If it's not, then they need to bring manufacturing home, even if it means opening their own plastics shop (traditional mold or injection mold, whatever). This wins the award for greatest design that seems like a gimmick and is actually 100% the real deal. Thank you, inventors & designers. You deserve all the buys. Science wins. Cheers & Good Luck.
