Stainless steel rods

[Lawrence Zarb]

I need some stainless steel rods to act as water level sensor probes for my fishtank, does anyone know where I can get hold of some?

[Andy Hall]

RS Components sell it.

You may find that some long stainless steel bolts fitted to a block of plastic would be a less expensive alternative.

For this application, go for 316 or A4 spec. which is food grade.

.andy

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[usenet]

Screwfix sell stainless studding in 1 metre lengths.

[PaulS]

welding supply stores. ask for ss tig rods. they come in various dia.

[Dan J.S.]

Keep in mind, stainless is not really stainless. They will eventually oxidize and rust. Just not as quick.

[Harry Muscle]

I think titanium will hold out longer in water. Also look into float swit , hey are usually better for aquarium use. I'm assuming you will be doing some kind of connectivity measurement to see if electricity can flow between two rods, right? If it can, then water is touching it. However, this would mean you would have electrical currents in the water, which might affect your fish badly.

Harry

[Lawrence Zarb]

Harry,

It will be used to connect to a water alarm circuit which in turn is connected to a water solenoid. When I do my 20% water changes I have plumbed in a system that, via carbon/water filters will fill up the tank directly from the mains by opening a stopcock. the solenoid is there to stop the water when it reaches a certain level (governed by the height of the rods) which shut the water off, just in case I forget to turn the tap off. This is because the water flow will be quite slow and it will take some time and I donot want to be wating for the tank to fill up..

[Andy Hall]

If this is not A4 food grade, then it is not appropriate for an environment with fish. Some species are very sensitive to metals, especially marine fish and invertebrates, alnthough some freshwater species are as well.

.andy

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[Andy Hall]

One important point, Lawrence, is to make sure that one side of the alarm sensor is connected to earth. Provided that you then have a very high impedance sensor input on the alarm circuit, it won't be a problem for the fish.

Another option, which I have used is to use a plastic float switch fitted to a plastic bracket. These are almost as accurate as contact arrangements and have the advantage that there are no metallic items in contact with the water at all.

RS Components part number 228-1986 is suitable and pretty cheap. I've recently used one of these in a water container which has a pump to provide misting for my snake vivarium. I wanted an arrangement that would stop the pump running if the container water level falls too low - I don't want the pump running dry. THe pump is normally turned on by a humidity sensor in the vivarium, but if the container water level is too low a beeper sounds instead to remind me to fill the container.

This application is not vastly different to yours in terms of what is needed,

.andy

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[Lawrence Zarb]

Andy, I have a float switch (a much easier solution) but it is just too big..