I've been thinking about getting a TDS meter (simple hand held type) and while researching what's available and the costs etc. I noticed that they work by measuring the electrical conductivity (EC) of the water. Presumably the method of measuring the EC in a TDS meter is exactly the same as the method used in a salt meter.
If this is correct, and both meters measure the same thing but just display the results in a different way (TDS meters in ppm and Salt meters in % salinity) am I right in thinking that I can use a salt meter (which I've already got) to measure my TDS just by converting the reading?
If so, am I right in thinking that a salinity reading of 0.03% is the equivalent of a TDS reading of 300ppm?
0.03% will give you 300ppm on the TDS, more common half oz per gallon will give you around 3000ppm on the TDS meter.
You need to take the pond TDS into account on top of this.
Ive found that some of the handheld TDS meters that calibrate at 240 or 340 ppm tend to be a bit out at the top end, the Hanna which calibrates at 1500ppm seems to give me more sensible numbers at higher TDS.
Thanks for the response. I'm not running RO, so don't need to be too accurate - would just like to know when the TDS increases and by how much really. Planning some changes and would like some comparison of whether they provide the improvement I want or if I've wasted my time and money!
Most TDS meters I saw were around £60 +, but I've just been directed to a hand held one for £15 on ebay - so I've placed my order!