Neptune Flow Sensor Reliability

ca1ore · Oct 18, 2019

I’ve gone rather overboard with flow sensors on my system, figuring that more data points are better than less. I’ve a single FS200 on my main return, a single FS50 on one of my refugia feed lines and then six FS100 at various points in the system. I’ve not had any issues with the FS200, nor with the FS50, but the FS100s regularly stop reading flow. Usually it’s necessary to un-plumb them, disassemble, and clean out the paddle/spindle assembly. Recently, however, I’ve been noticing that the small magnet that sits at the top of the paddle (I’m assuming it’s a magnet) is beginning to disintegrate on one of them. Not rust per se, but clear disintegration. Unfortunately I’ve not labeled the sensors, so while I’d guess it’s one of the older ones, I don’t know that for sure.

The earliest FS100 is about 2 1/2 years old, the others varying from brand new to 2 years. I plan to inquire of Neptune whether they will/can sell me the paddle wheel assembly. More importantly, I’d be interested to hear from others using these sensors whether you see similar magnet disintegration .... or whether mine is an outlier.

If you use these sensors, and have not opened them up, it might be prudent to take a peek.

reef lover · Oct 25, 2019

Bump for views!

ca1ore · Oct 25, 2019

Neptune replaced the sensor but failed to offer any insight about the rotting magnet.

themcfreak · Jan 13, 2020

I am a few months late to this thread, but I have run into a similar issue with my 1" sensors. My 1/2" sensors are fine, but the 1" magnets have fallen apart. I opened a ticket with them, but mine are out of warranty. They asked for pictures, but I had gone out of town while the ticket was open, and when they closed the ticket, they said they do not sell the impellers individually, and that I would have to buy a whole new sensor. If I had been able to respond with a picture, maybe they would have sent replacements, but either way, I do wish they sold them on their own. My sensors are essentially a waste at this point, because I have not been able to buy entirely new ones yet.