Common garden tools and swimming pool skimmer/nets work for removing weeds and filamentous algae. The speciality tools are more costly, but work better (efficiently) and you can get more done faster. It depends on preference.
I have a Lake Rake, Beechcomber Rake and an extendable handle smelt dipping net (F.algae, leaves & floating material) that I loan out to interested customers to take home, try out, and compare with their tools . After using and comparing, just about every one buys one or both of the items.
Early on I used the numerous homemade and garden/pool tools methods. They all worked with varying degrees of success. I finally broke down and bought my first lake rake and liked it so well I started selling them. Since then I used other speciality pond tools most were worth the money in time and effort they saved me over the years.
I have yet to make the big purchase of the underwater sickle bar mower ($2200) that is currently advertised in PBoss mag; Jenson Lake Mower, San Marcos TX.
www.lakemower.com. Does anyone have one of these or have you used one? I think it would be a good item to have if want to clear just certain areas of weeds and leave other weedy areas standing for habitat and competition to filamentous algae. If you remove some types of underwater weeds before they produce seeds and winter buds you can achieve pretty good control after several years of preventing reseeding and bud formation.