Madison M8000 Liquid Level Sensor, Miniature Vertical Float Switch, Polypropylene, 1/8" NPT

Works well and easy to install.

I bought two of this as part as aquarium automation with Neptune Apex breakout box. I have a 20 gallon tank/reservoir to store RODI water as top off water of saltwater aquarium. I place the float switch in the reservoir so that when the water level is low, the automation system will notify me via email and SMS. It works fine. It also integrates with camera and Samsung SmartThings light to take photo automatically. The other float switch is sitting in the sump to notify me when the water level is low. They are working fine so far.

I have yet to actually install this. But I have tested it and it works both ways, NC or NO. The build looks and feels more substantial than what I am replacing. My only gripes are the length of the leads and the absence of a nut.However, I found an easy solution to the no nut problem. Amazon sells a Spears 438 Series PVC bushing that works perfectly. You can find it here: Spears PVC Pipe Fitting, Bushing, Schedule 40, White, Spigot x NPT Female. Just make sure the 1/8" NPT female size is selected. It will take the place of a nut and was only $0.78 when I wrote this.Alternatively, Grainger also sells a reducing bushing that works. It's a LASCO 438071. Price was $0.80 when I wrote this.UPDATE: I have now installed this switch and it has been working for a couple weeks. I had to re-drill the hole in the mount I am using because the 1/8 NPT was much larger than the old connection. The switch has been working just like it is supposed to. I intended to put this switch into the slosh/snail guard I had on the old one. But this switch is taller and it would not fit. So if you want to reuse your existing setup, take this into consideration. The M8000 has functioned well even without the slosh guard. As an alternative, I purchased this: Madison MS8000 Plastic Miniature Liquid Level Switch with Slosh Shield, 30 VA SPST, 1/8" NPT Male, 100 psig Pressure. It's a little pricey but this is not the kind of thing you want failing on you. The return area in my sump isn't too sloshy, but you still want to protect from the rogue snail. I will place the MS8000 at the control level and the M8000 just above it for redundancy. I feel very comfortable with this setup and have no fear that my sump will be overfilled.

perfect

Wanted to add a note here since it isn't mentioned anywhere--- This float switch can be used in a normally closed or normally open circuit configuration just by flipping the float 180° on the shaft. The retaining E clip at the end of the shaft easily snaps off & the float can be flipped to change how the circuit will behave at high or low water.I use the float switch to trigger an audible alarm when my water jug that's filling with RO water gets full. The flow rate into the jug is slow, 1 gallon/25 minutes.Twice now, this float switch has stuck and not floated - causing a flood when I discovered it too late.Since those last two floods, I exercise the float on its shaft, up and down a few times to ensure its sliding freely before filling the jug. Ever since then (about 6 months now) it hasn't jammed and had alerted me to a full jug.Bottom line:If the water level is rising very very slowly, this float switch could possibly not move and not do what it's supposed to do.

There is NO included top nylon nut to secure it to anything, I guess it's my fault for assuming that a float switch would include the nut. Literally EVERY other float switch I have EVER bought has has a fixed bottom nut and a removable top nut. Now I have to drive into town and test fit whatever I can find if I can find any, and since I'm trying to use these in a saltwater application I can only use nylon nuts. It's not a part you can buy, they all have odd thread sizes (somewhere in the 7/16" size I think) try to go to a big box store and buy a 7/16" nylon nut, not going to happen I just tried. Unfortunately the lack of a simple nut means my review focuses on missing parts instead of function. I can say that Madison M8000 float switches are highly recommended in the reefing community.

This is by far the best float switch for just about anything. You can use 2 or 3 in tandem to create all sorts of dead bands for Lead and lag pump applications.Although, it is not wise to say "This switch crapped out on me" and the reason being because you thought it could directly switch your inductive load without the use of an isolation control relay (known as an ice cube relay). If this switch is used with a relay and is not used with voltages higher than 24 vdc or 120 vac , and your smart enough not to set this magnetic reed type float switch near an interfering magnetic field, well than congratulations because these floats last FOREVER when you know how to use them.When you don't know what your doing with these float switches, you wind up writing less than a 5 star review and complain about there not being a nut! As soon as you look at it you know it needs to be set into a 1/8"-27 tapped hole of a substantial thickness (at least 1/8") of plastic or metal sheet with teflon tape around the threads of the float switch. How else would you seat the taper of the threaded switch without being driven loose by vibrations? Definitely not with a nut and that's why it doesn't come with one. Get yourself a 21/64" metal twist drill bit and a 1/8"-27 npt tap (about 10 bucks) and set this the right way without a nut if there's no 1/8" npt tapped hole there already where you intend to set the thing.

These are quality units.NOTE: I have seen some reviews that are dissatisfied because there is no mounting nuts. They must have missed the fact that these are pipe mounted and those threads at the top are NPT threads.