TDS meters

[smallfry53]

In the last year I've tried to get a better understanding of water parameters. I used to just test nitrogen, and ph. Lately I've been testing gh, kh, and tds, which from my reading seem like they are at least as important as ph.

Anyways, so I bought an HM EZ tds meter. Then a few weeks ago I decided to buy an HM TDS-3 meter so I could see if they gave me the same results.

The first tds meter typically reads around 200-220, but now the new meter reads 155-170ish.... I figured there would be a slight variation, but now I'm wondering if these meters are good for anything.... If I get another one is it going to tell me my tds is 300?

Is there any way to calibrate them? or maybe I'm doing something wrong....

 

[ZxC]

What units are they measuring in?

 

[Delapool]

Following this as hoping to try new tds meter on weekend...

 

[smallfry53]

What units are they measuring in?

Both are ppm.

 

[ZxC]

So, the issue I have with TDS meters is that they all seem to vary from one another, for whatever reason (calibration method/solution, temperature probes, units of measurement etc. etc.).

Not only that, but TDS of your tank water can be made up of absolutely anything, some meters only detect certain salts.

So, to “fix” this stick to one individual calibrated meter, and only compare values to your own tank. If my tank runs good at 200 ppm, your tank will be way different. Again, only use one meter, and only compare measurements from your tank. One meter is different than the next.

 

[smallfry53]

Right.... I understand that getting a baseline, and watching fluctuations is probably the most important part. So they aren't totally useless, but with that much variation from one to another it makes the actual value pretty useless. I guess with almost everything in this hobby consistency is the goal....

 

[ZxC]

Right.... I understand that getting a baseline, and watching fluctuations is probably the most important part. So they aren't totally useless, but with that much variation from one to another it makes the actual value pretty useless. I guess with almost everything in this hobby consistency is the goal....

Exactly, same goes with our liquid test kits, they are affordable hobby grade instruments..... not certified lab grade testing equipment. A baseline check followed by periodical checks to monitor changes is about the best we can do with TDS meters.

 

[coralbandit]

I would try to test the two meters with known values .
I know when done right my RO/DI is 0 so for me that is a easy test.
I have had other meters besides my HM3 and they were all different.
I have burned up a couple HM3 and in the time I didn't have them it caused a little stress for me not to know exactly where my water is ,but when the new meter arrived the water was still in line according to the meter. Point my HM3s are consistent ,the others [I gave them away] not so much ...
With years on some of my HM3 I have never calibrated or felt the need to ?
I get 0 on my RO/DI every time no matter how funky another tank may be...
My water is 350 and I just tested my Alpha swordtail tank...
1127 ppm ! I add wonder shells to that tank but still make large waterchanges .
I never would have guessed without a meter.
It may not matter much but I was getting ready to move them to another tank when I realized..The meter might have saved my fish ? 1127 to 350 ?
I like my meter but it like all other test ..Just a reference with some insight .Definitely a short story not a novel. But still handy and IMO important..

 

[Caliban07]

I would try to test the two meters with known values .
I know when done right my RO/DI is 0 so for me that is a easy test.
I have had other meters besides my HM3 and they were all different.
I have burned up a couple HM3 and in the time I didn't have them it caused a little stress for me not to know exactly where my water is ,but when the new meter arrived the water was still in line according to the meter. Point my HM3s are consistent ,the others [I gave them away] not so much ...
With years on some of my HM3 I have never calibrated or felt the need to ?
I get 0 on my RO/DI every time no matter how funky another tank may be...
My water is 350 and I just tested my Alpha swordtail tank...
1127 ppm ! I add wonder shells to that tank but still make large waterchanges .
I never would have guessed without a meter.
It may not matter much but I was getting ready to move them to another tank when I realized..The meter might have saved my fish ? 1127 to 350 ?
I like my meter but it like all other test ..Just a reference with some insight .Definitely a short story not a novel. But still handy and IMO important..

Probably wouldn’t have liked that move. After losing ottos repeatedly from my LFS I decided to check the TDS of their water which is the same tap as mine 60-90ppm. 660ppm it tested out at while my tank is 160ppm. And that’s only the charged ions the meter will actually detect! It makes you wonder what the hell is going on in that shop. Won’t be buying from there anymore.

 

[Coralocean]

The only problem with TDS meters imo is they don't tell what the solids are. Of course if you are doing salt water you want to start with 0 TDS. That's on my list to get as well as a r/o unit.

 

[smallfry53]

Thanks for everybody's input. I kind of wonder if the HM 3 isn't more accurate. Probably 3/4 of my ram eggs have been fertile, and if my tds was over 200 it seems as though I wouldn't have that many fertile eggs (if any). Now if only I could get them beyond the wiggler stage... lol

I'll pick up a gallon of distilled water soon and see what I get. This kind of makes me want to get another meter and see if it matches one that I already have. It still kind of bothers me that I don't know which meter is right, if either one is....

 

[coralbandit]

The only problem with TDS meters imo is they don't tell what the solids are. Of course if you are doing salt water you want to start with 0 TDS. That's on my list to get as well as a r/o unit.

When I advocate TDS meters I hear this a lot...
So tell me what does your GH and KH test tell you is in the water exactly ?
They are more accurate then a half blind persons color rendition any day to me.. I believe they measure 'salts' in general like all "hardness" test. None give any definition .. They should be used as a reference .
If you want help on your rams ask ..
I believe I have at least a pair every year spawn in my tap unintentionally that ended up being rams I raised . I think they can adapt to different water over generations possibly. They are far from wild fish no matter where we all get them from.

 

[Caliban07]

When I advocate TDS meters I hear this a lot...

So tell me what does your GH and KH test tell you is in the water exactly ?

They are more accurate then a half blind persons color rendition any day to me.. I believe they measure 'salts' in general like all "hardness" test. None give any definition ..

GH and KH tests don’t give you any reliable information. TDS meter is the most accurate hobby grade test kit we have. So +1 on them. Unfortunately although reliable, still nothing useful apart from ion trends.

Sugar is still a dissolved solid but it won’t show up on the conductivity meter aka and wrongly named TDS meter [emoji846]

 

[ZxC]

If using 100% RO and remineralize with Ca and Mg sources we can get pretty close using the gH kits, same if using baking soda for example with kH. But as for tap, I agree, no clue what is actually the correct ratios of minerals making up the hardness.

 

[Coralocean]

When I advocate TDS meters I hear this a lot...
So tell me what does your GH and KH test tell you is in the water exactly ?
They are more accurate then a half blind persons color rendition any day to me.. I believe they measure 'salts' in general like all "hardness" test. None give any definition .. They should be used as a reference .
If you want help on your rams ask ..
I believe I have at least a pair every year spawn in my tap unintentionally that ended up being rams I raised . I think they can adapt to different water over generations possibly. They are far from wild fish no matter where we all get them from.

Point taken. I'm scared to see what my TDS is lol. That's why I am seriously shopping for a R/O unit and will certainly get a TDS meter then. I can actually keep rams with proper water and a shrimp tank at some point.

 

[smallfry53]

If you want help on your rams ask ..

I appreciate it. I'll probably have some questions for you soon. I have only stole the eggs a couple times, I was giving them a chance to try to raise them on their own... which as expected didn't go that well. The first time I stole the eggs I put my breeder box a bit too low and had an intruder get in and eat all the eggs/wigglers. About a week ago I saw most of the eggs had been eaten after about 12 hrs. which is unusual for them, but I stole 40-50. I had about 30 wigglers, and then came home from work and they were all gone/dead?... not sure what happened... but looks like in a few days I'll have another batch. I probably need to get a dip and pour so I can dose methylene blue. That may have been the issue. I also wondered if some of the wigglers wiggled out of the breeder box and were eaten, which goes back to using a D&P I'd guess.

As far as tds goes.... I do appreciate you guys' knowledge. You guys have helped my understanding as well as others it seems.