got a TDS meter, couple questions for pros

[Jack L]

i've only use drops for hardness, GH KH etc before.

so i got the TDS meter rec'd on board, calibrated it with the 342 solution

anyway.
my fresh tap is 260 (and seriously disgusting! I've tasted better pool water)
my ro is 15
my softened water is 244 (is that because its about the same amount of solids, but just salt instead of calcium and magnesium?)
my tank that is RO with seacheam suite put back in is 230.


but aged tap (still tastes bad) is 440
aged tap that has API aquatic plant media in it reads 330
-i have that as i was testing the impact to ph, which it did drop pH by 1 when the api media was added

question
1. does it make sense that aged tap is so much higher? i know he pH climbs when i age it, but why would that mess with dissolved solids?
2. does it makes sense that tap with the api plant media is less?
- because i expected it to be higher as i thought the media would add more dissolved solids.

and let me just apologize ahead of time if these questions just made any of you dumber, i'm i'm probably missing something basic.
thanks

[DJW]

Here is a good article on TDS meters:

http://reefkeeping.com/issues/2004-04/rhf/feature/index.php

Also check to see if your meter automatically adjusts for temperature. If the aged water was warmer it would show a higher value if the meter doesn't compensate for temperature.

My amateur guess is that the API plant stuff has particulates that interfere with conductivity, which is all you are really measuring.

[FishFanMan]

I think aging the tap water allows co2 to be released from the water and thus the ph to go higher but the biproduct of co2 release if left behind in the water like Sodium which will drive up the TDS.

The API product probably contains material that adsorbes ions like calcium which will drive down TDS.

[nc0gnet0]

temperature

[Jack L]

temperature
All temps same, room temp about 72, except tank water was 84

[Jack L]

Thanks I'll check it out

[Jack L]

HM Digital TDS-3

I think discus stu referenced it and others mentioned the EZ
Version, when I went searching again on board I was getting no results which may be was because of the short search string... but not sure

[DonMD]

Wonder why your ro is 15 ppm. Shouldn't it be zero?

[DJW]

Wonder why your ro is 15 ppm. Shouldn't it be zero?

If RO removes 95% and you start with 400 ppm, you end up with 5% or 20 ppm. That's what mine does.

[DJW]

my fresh tap is 260 (and seriously disgusting! I've tasted better pool water)
my ro is 15
my softened water is 244 (is that because its about the same amount of solids, but just salt instead of calcium and magnesium?)
my tank that is RO with seacheam suite put back in is 230.

From these numbers it looks like you don't need RO anymore if you are bringing the TDS right back to tap water level, almost.

[DJW]

This is from the HM Digital instructions:

"Our meters are capable of compensating for temperature by simultaneously measuring the conductivity and the temperature. The internal electronics then take the temperature into account, and normally provide a value that is "corrected" to what the conductivity would be at a standard temperature (25°C)."

Its not clear why the TDS is higher in your aged water. The same document implies that CO2 adds conductivity.

[Jack L]

I don't think the softener and then the RO get it all

[Jack L]

From these numbers it looks like you don't need RO anymore if you are bringing the TDS right back to tap water level, almost.

i thought of that....but...

these concerns.

1. though the TDS is same, when it comes from City, i don't know what is making up that number. for example, it reads the same TDS for city water as it does for my water softener water, one has calcium, one has sodium, and i know that plants didn't do great in softened water. my guess though, is that the city water would do fine by the plants with the mineral mix in it.
2. my city water has nitrate of about 40, but i think Seachem safe would fix that.
3. even though my tank TDS is near same number as city, something is different, my tank is not being covered in limescale, whereas anything that i used city water on does quickly get covered in limescale

city pH is 8.4, though i don't think that matters to fish.

[DJW]

Makes sense... eliminate the sodium which plants don't like, and eliminate the nitrates. I use RO mostly because of nitrates, but when I put minerals back I shoot for a TDS of about 90 for general purpose water. This lower TDS saves on seachem powder and its softer water too. The plants might do better with more TDS than 90, but I think that depends partly on the type of substrate. What works for plants or doesn't work is baffling to me sometimes.

[Jack L]

Makes sense... eliminate the sodium which plants don't like, and eliminate the nitrates. I use RO mostly because of nitrates, but when I put minerals back I shoot for a TDS of about 90 for general purpose water. This lower TDS saves on seachem powder and its softer water too. The plants might do better with more TDS than 90, but I think that depends partly on the type of substrate. What works for plants or doesn't work is baffling to me sometimes.

nemonic do you have tank pics on here?

[Jack L]

my latest learning with plants is how the heat destroys some of them!

[DJW]

Just one I think, but that was plants.

[DC Discus]

Hi Jack,

This site might help a little with the differences you're seeing;
http://www.tdsmeter.com/faqs/

tab - Why do I experience different readings in the same water with the same meter?
tab - How can I get the best possible readings?

Cheers,
DC

[Jack L]

Hi Jack,

This site might help a little with the differences you're seeing;
http://www.tdsmeter.com/faqs/

tab - Why do I experience different readings in the same water with the same meter?
tab - How can I get the best possible readings?

Cheers,
DC

thanks DC, very helpful.