Dolphin M400

30kgal

New member
Mar 10, 2019
4
Southeast Louisiana
Just bought a dolphin m400 after having the DX 3. I’m not impressed I’m trying to return it. When I pull the robot out of the water, a considerable amount of debris falls into the pool. Some fine debris would leak back in with the DX 3 but nothing like the m400. The difference DX 3 had spring loaded plastic flaps that close after cleaning. The M400 has cloth flaps and they don’t close. I welcome any suggestions on a fix. I sure hope the store allows me to swap it out for the DX3. Fingers crossed
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,101
Tucson, AZ
On the my S300i (S series), the cloth “one way” flap has two metal rods at the top so that when the suction stops they fall to the side and that closes off the opening. Works line a charm. I don’t get a lot of large debris though and I suspect if I let the filter basket get crammed full of debris, the flap would not close properly.

Are you regularly cleaning out the unit?
 

30kgal

New member
Mar 10, 2019
4
Southeast Louisiana
On the my S300i (S series), the cloth “one way” flap has two metal rods at the top so that when the suction stops they fall to the side and that closes off the opening. Works line a charm. I don’t get a lot of large debris though and I suspect if I let the filter basket get crammed full of debris, the flap would not close properly.

Are you regularly cleaning out the unit?
That’s exactly what happened. The flap was full of debris mainly leaves, which is why I wanted the dolphin. I just didn’t have that issue with the plastic spring loaded flaps on the DX3. The bag on the DX3 may have been annoying to rinse out but held so much more leaves. If leaves are an issue in your pool, I would suggest getting a unit with a bag.
 

BowserB

Silver Supporter
Jul 29, 2018
181
Katy, Texas
My M500 has the system like Matt's S300i, and I've watched closely when I pull it out (feels like about 50 lbs when full of water!) and I see nothing coming out. Since the M400 and 500 are essentially the same except for the nearly useless Bluetooth/iPhone app for programming the M500, I might guess there has been an upgrade your dealer could provide you with. Given the huge markup on these dealer models, I think they could afford a free upgrade.

Other point Matt made. I could see if crammed full, debris might prevent the closure. I run my M500 about every 2 or 3 days. At the end of the 3.5 hour run, I take it out, cleanout the baskets, rinse the cleaner completely of residual pool water (and chlorine), rinse off the power cable, and store it on the caddy with the basket doors open. After it has dried, I cover with an outdoor chair cover to protect from the sun.