Differences Between Pool Cleaners


Active member
Oct 18, 2016
Long Valley, NJ
Hi. New (as of last summer) pool owner here. Pool is vinyl-lined, 20x40, Grecian shape, 29,000 gallons. We're in NJ. Pool faces south, so it gets lots of light, but we're in a very open yard, so we don't get too many leaves or wind-blown debris.

I posted on this forum a while ago about making some plumbing changes to our pump area, which is a mess right now. One thing that folks agreed on unanimously was to ditch the boost pump and water-powered Polaris 280 and upgrade to a robot.

I'm in the process of researching pool cleaning robots now so I can be ready for when we open the pool in a few months. I've settled on Maytronics, as they seem to have the most positive reviews. Unfortunately, the Maytronics website is very lacking in detail about each cleaner, and I'm confused about the differences between the S300, S300i, M400 and M500. Thus, despite all the reading I've done on this site, I'm confused about which one will best meet my needs.

For what it's worth, I'm a "buy once, cry once" kind of person, so I'm OK spending more on a cleaner if it's worth it for my needs.

Here are my most pressing questions:

1. Differences between M400 and M500?

2. Differences between S300 and S300i?

3. Practical differences between the M- and S-series?

4. Do folks with experience feel that the M-series would be that much better than the S-series for my situation?

5. Which one is the best for "throw it in the pool, let it clean for a few hours, easy clean up, and repeat?"

6. What is the expected lifespan of these things? One of the pool stores I called said "we have people who have been running theirs for 5 or 6 years and they still work..." 5 or 6 years is good!?

Thanks for your help!


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
FL panhandle
I don't know about the Ms. Lots of happy folks with the S series cleaners. The only real difference between s200 and s300 is blue tooth so you can drive your robot around the pool. Which nobody seems to really want to do after the first day. The S200/Doheny's Discovery can run daily for a week before it shuts off so you don't have to clean it daily if there isn't much debris load. More about mine in my pool thread, link in sig. And also more here, First Robotic Cleaner, Doheny's Discovery

I don't know about life span. Maytronics is willing to give them a 3year warranty so that's a pretty good start.


Active member
Jan 31, 2017

sounds like you and I are a lot alike. I recently bought the S300i, and did 2 weeks worth of research including becoming a member here. I talked to Maytronics support multiple times and brick and mortar dealers through several different states, including several in my local area. One large reason I settled on the S series was the Bluetooth functions, the the S300i in particular was to have the full Bluetooth capability along with the double layer debris basket. And yes I do use the Bluetooth, for scheduling, cleaning modes and steering control.

One thing the M series has that the S doesn't is the third brush, there is a brush in the middle (bottom) of the M series that acts as a third scrubber. But they are also a few hundred dollars more, and have a 3 year warranty. The M series is also dual motor making it have better turns. When I bought the S300i Maytronics was offering a promotion that extends the warranty by 6 months, you may want to check to see if it is still running. Plus if you have an AMEX you can get another year extension from AMEX.

I will PM you a couple videos I made about Maytronics and the unit I have. This process was very confusing and had some complexity to it, finding units that were sold online but without warranty, units that perform the same functions but have different name and colors, crazy.

If you are ok with spending more, I have heard the M series is more popular and performs better, and plus they released an update to the M series this year which makes them Bluetooth capable like the S series. I was able to get the S300i for $1150, the M500 was $1500 and I couldn't find it lower than that, I think the M4 was $1400. So the difference in price was worth sticking with the S series, and it has done a great job so far. It picks up fine debris and large leaves great.

Here is a review I did of the S300i

Ask me any questions if you have more.

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