Dolphin S300 review

This is a source-based assessment of the U.S. Dolphin S300, Product No. 99996221-USWI, not a hands-on test. Maytronics lists a corded robot for floor, wall and waterline cleaning in pools up to 50 ft. The exact page also names MyDolphin Plus, a two-hour default cycle, a weekly timer, a caddy and an additional Ultra-Fine Filter Kit in the box. Those facts make the S300 a different proposition from the similarly featured but separately numbered S200; they do not establish installation fit, cable reach or the contents of an individual seller's carton.

A connected corded routine

The U.S. product table lists MyDolphin Plus and Wi-Fi connectivity. Maytronics says the app can schedule cleanings, choose cycle options and spot clean. That is more useful evidence than an undefined “automation” label alone, but the page does not specify every app function, the available cycle durations or what works while the robot is underwater. It separately lists Delay Feature: No and Remote Control: No. I would not translate “app control” into live steering or a delay timer when those exact fields say otherwise.

The page lists a two-hour default and weekly timer. The exact comparison table does not list alternative durations for the S300, even though its marketing copy mentions app cycle options. Treat the two-hour value as the listed default, not proof of a choice among particular cycle lengths. If someone needs a specific schedule, cycle, or out-of-water action, the best next step is to confirm that exact function in current S300-specific documentation before buying.

Coverage is broad on paper; the 50-foot figure has a narrow meaning

Maytronics lists floor, walls and waterline coverage, plus a maximum pool length of 50 ft. It also lists rectangular, round, free-shape and kidney shapes and both in-ground and above-ground classifications. These are useful screening fields, not independent performance results and not a promise for every slope, corner, tile transition or waterline. They do not tell a pool owner whether a particular step or sun ledge will be climbed or cleaned.

Do not mistake the maximum pool length for the tether length. The exact page lists an anti-tangling swivel and plug-and-play operation, and the page-linked image visibly shows an S300-marked body with an attached cable. Those support a corded classification, but neither the table nor the image tells us how long the cable is, where the power supply should sit, or whether an outlet-to-pool route is safe. Maytronics' exact-number manual selector for 99996221-USWI currently returns no products. Minimum water depth, finish suitability, step limits, placement instructions and the detailed care routine therefore remain unverified here.

Filter and caddy claims are model-specific

The exact product table names a Fine Filter Kit and separately says an additional Ultra-Fine Filter Kit is in the box. It also lists top access and no full-filter indicator. Maytronics provides no particle-size grade for the word “Ultra-Fine”; it should not be turned into a micron specification. The same table names a caddy as included. That is a documented package field for this reviewed configuration, but a seller's open-box, refurbished or bundled offer may differ, so check the exact product number and carton description.

Maytronics also lists two standard brushes, an active-brush field, waterline scrubbing and a 4,000 GPH suction rate. The rate is a manufacturer specification, not a measurement from this assessment or a head-to-head test. Separate accessories shown on the product or parts pages—including filters, caddy covers, replacement cables and brushes—do not establish extra in-box items or compatibility with this exact U.S. SKU.

How it differs from the S200

The S300 (99996221-USWI) and S200 (99996202-USW) have distinct U.S. product numbers and UPCs, so I keep them as separate assessments rather than treating a shared feature list as proof of identical hardware. Their exact pages overlap on a 50 ft maximum, floor/wall/waterline coverage, two-hour default, weekly timer and a named in-box Ultra-Fine kit. The S300 page additionally names MyDolphin Plus and says a caddy is included. The S200 page says Mobile Application: No, while its caddy field was not unambiguously resolved from the captured comparison row. This is a real difference in documented controls and package evidence, not a claim about internal components.

The S300 page lists an 18.5 lb robot weight and dimensions of 17.433 x 15.839 x 11.717 in, with a 23.7 x 19.4 x 19.0 in package. These are catalog values, not independent measurements. It also lists a two-year warranty; confirm current terms for the exact U.S. offer. None of these details replaces the missing model-linked manual or establishes a pool's cable layout and safe operating limits.

Bottom line

The S300 belongs on a comparison list when a corded robot with documented three-area coverage, a 50 ft pool rating, MyDolphin Plus scheduling/cycle/spot-clean features, a listed caddy and an extra in-box Ultra-Fine kit fits the requirements. It is not the obvious choice for a cordless setup, a buyer who requires no app, or a pool whose step depth, finish, cable route or installation constraints need a verified manual answer. Before deciding, confirm the exact 99996221-USWI listing, current instructions, seller package, warranty and return terms. No price, current stock, independent test, ownership or customer experience is claimed here.

Sources: Maytronics' exact U.S. S300 product page; its linked exact-number manual selector (no product returned); the page-linked S300 image; and the separate U.S. S200 page for the expressly limited comparison above.