TDS meter question

wnaing

New member
Just out of curiosity. I have very little knowledge with TDS meter. So forgive me with a stupid question. What is the typical TDS range for the normal ideal tank set-up? Can TDS meter be used to determine the time for fresh water change or TDS is not the only factor to perform water change?
 

Angler02

New member
You use the TDS meter on fresh water from your RO unit or however you get your fresh water. TDS meter measures PPM Parts Per Million, which is basically any junk in the water.
 

wnaing

New member
Angler, thank you. I wonder it can be used for measuring the tank water. I heard saltwater tank range is 5000 to 50000 ppm (correct me if I am wrong). If I buy a TDS meter with that range, can I use to gauge water change measure. Just thinking...
 

logiktest

New member
Tagging alonge...

I've only used my TDS meter for testing fresh RODI. Zero is the desired number...

I would be interested to see if there is another way to determine when waterchanges are necessary other than just performing them on a regular basis.
 

Angler02

New member
I wouldn't think your TDS would be a way that you could decide it's time for a water change. A tds meter's opinion of your water quality would solely be based upon how many particles are in the water, which could vary in many different ways. JMHO For that matter I guess the same could be true for any other test kit. The only difference is that a test kit would give you answers based upon a chemical response and the TDS meter through a probe.
 

breutus

Don't ask me, I'm wrong.
The problem is that a TDS meter measures everything... They can be used for other things if you have a highly accurate one. Such as when premixing salt in fresh RO that has a TDS of *0* you can add salt based solely upon TDS if you know the number of salt particles (ppm) it takes to make you 1.025 salinity.

But when it comes to in the tank... you have SOOOO many variables from everything in your tank how would you know what the number was referring to
 

Schplitter

New member
<a href=showthread.php?s=&postid=14792594#post14792594 target=_blank>Originally posted</a> by breutus
The problem is that a TDS meter measures everything... They can be used for other things if you have a highly accurate one. Such as when premixing salt in fresh RO that has a TDS of *0* you can add salt based solely upon TDS if you know the number of salt particles (ppm) it takes to make you 1.025 salinity.

But when it comes to in the tank... you have SOOOO many variables from everything in your tank how would you know what the number was referring to

Sorry but I have to add to this. This is true only if you had pure NaCl. Since our salt mixes include many other things like Ca and Mg and all the other things we don't test for this would not work. That is unless we get IO to keep the batches perfectly acurate...

JMO,

BK
 

breutus

Don't ask me, I'm wrong.
I hadnt even thought about that your totally right BK yeah there is just to many variables on to many levels to use them for other than there intended purpose of test general contaminants in "pure" water
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Someone just pointed this out so I thought I'd comment here ...

It would work perfectly fine if you had the right range on the TDS meter, and some do but most do not. You'd need it to read into the tens of thousands of ppm TDS. :)

TDS is a measure of conductivity, and conductivity is the most preferred method for measuring seawater salinity by chemical oceanographers. I use a meter that has the right range, and many hobbyists use the Pinpoint salinity meter which also has the right range.

These have more:

Using Conductivity to Measure Salinity
http://www.aquariumfish.com/aquariumfish/detail.aspx?aid=1804

Reef Aquarium Salinity: Homemade Calibration Standards
http://reefkeeping.com/issues/2004-06/rhf/index.htm
 

twizzlerman77

Short Bus Rider
WOW! I have never seen Randy here before he usually sticks to the reef chemestry forum. I enjoy reading your posts, please try and post on our forum more frequently.

Your knowledge and kindness in this hobby seems endless, and i like how you almost always add a link to further explain yourself. Keep up the good work.
 

Angler02

New member
He also has a ton more posts than Dave which to me is amazing in itself!!! Thank you for the info and your time.
 
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