What is conductivity and how do you measure it?
What difference does it make and everything else associated with it that you can tell me?
What difference does it make and everything else associated with it that you can tell me?
Conductivity?
- Thread starter Skittyfish
- Start date
Conductivity is how well the water conducts electricity. Pure water is not a particularly good conductor; however, when you add dissolved solids these dissociate into ions. Ions allow water to conduct much better. Conductivity is therefore measured to gauge the TDS, or Total Dissolved Solids, of the water.
I don't know of any hobby tests for it, as it is seldom done. We are usually interested in the concentration of a particular ion, rather than the TDS. However, perhaps we should be looking at TDS more? There is a worthwhile debate there methinks.
Conductivity, incidently, is by definition the opposite of resistance. Since resistance is measured in Ohms, conductivity (IIRC from A level physics) is measured in Mhos. Yes, physicists do have a sense of humour.
I don't know of any hobby tests for it, as it is seldom done. We are usually interested in the concentration of a particular ion, rather than the TDS. However, perhaps we should be looking at TDS more? There is a worthwhile debate there methinks.
Conductivity, incidently, is by definition the opposite of resistance. Since resistance is measured in Ohms, conductivity (IIRC from A level physics) is measured in Mhos. Yes, physicists do have a sense of humour.
It indicates the TDS of the water. Some fishes come from waters naturally low in TDS, others from waters high in TDS.
What it really means for aquaria is that folk who keep low-conductivity fish such as Discus and Tetras are kidding themselves when they "soften" the water by adding more ions to it - such as salt-exchange "water softener pillows".
The major impact is for breeding - fish are quite adaptable to water's conductivity or TDS (aquarists use TDS as more easily/cheaply measured than conductivity), but egg membranes are not as adaptable. You can keep blackwater and "soft" water fish in most tap water, but you may not be able to breed them.
The major impact is for breeding - fish are quite adaptable to water's conductivity or TDS (aquarists use TDS as more easily/cheaply measured than conductivity), but egg membranes are not as adaptable. You can keep blackwater and "soft" water fish in most tap water, but you may not be able to breed them.
The conductivity of water is measured in units called Siemens per meter. In the aquarium you'd use microSiemens per centimeter. This requires a special handheld probe tester that measures a minute amount of electricity passing between probes that are a centimeter apart. I've never actually handled one of these myself. But if you're using r/o water and want to know just how much of your tapwater to mix with it in order to match the water in the aquarium, or if you want to test whether your D/I membrane or resins are still effective, well, you should know your way around conductivity testing. A good way to dive into this area is with a www.google.com search: "test conductivity aquarium water microSiemens."
-cut n' pasted from www.skepticalaquarist.com , in Water/Dissolved Minerals. There's a link or two about the "Kirschbaum method" of breeding low-conductivity (RTR's good phrase!) fish in low-conductivity ("soft") water.
-cut n' pasted from www.skepticalaquarist.com , in Water/Dissolved Minerals. There's a link or two about the "Kirschbaum method" of breeding low-conductivity (RTR's good phrase!) fish in low-conductivity ("soft") water.
A quick bit of googling and it transpires that Mhos started to be called Siemens in the 70s.
Perhaps physicists' senses of humour have been dulled.
Perhaps physicists' senses of humour have been dulled.