Which TDS meter to get?

Get the handheld HM Digital COM-100. Its 10x more sensitive and accurate than any other meter available in the hobby. It can be calibrated in three different ways for extreme low end accuracy for DI water.
 
OK, I ordered the $21.00 - HM-4 DIGITAL TDS TESTER one, is that one OK? They don't have anything called COM-100.
 
You do want temperature. You use it to calculate RO efficiency. Get the good one the first time. The COM-100 also measure true electrical conductivity which is much better than TDS.
 
AZDesertRat - I don't know if I want to spend that much on a meter though, that's quite a bit more, plus I already sent in the order a while ago.
 
You get what you pay for. The meter you ordered is not of the same quality as the COM-100. I have owned that same one and while it worked it was not as accurate or sensitive as I was looking for. Neither are the inlines and I have two of them. The COM-100 can be had for as low as $39 some places I have seen recently and is well worth the difference.
How important is the quality of your water to you? Remember before answereing it isthe single largest ingredient in you system and everything depends on it.
 
Where do you order it for 39? Maybe I can call up the filter guys tomorrow early and have them cancel the HM-4.
 
<a href=showthread.php?s=&postid=9576369#post9576369 target=_blank>Originally posted</a> by AZDesertRat
You get what you pay for. The meter you ordered is not of the same quality as the COM-100. I have owned that same one and while it worked it was not as accurate or sensitive as I was looking for. Neither are the inlines and I have two of them. The COM-100 can be had for as low as $39 some places I have seen recently and is well worth the difference.
How important is the quality of your water to you? Remember before answereing it isthe single largest ingredient in you system and everything depends on it.

The accuracy of the TDS-3/4 and the COM-100 is at +/- 2%... how is the COM-100 that much better?
 
You calibrate it with low range solutions so its 2% of a smaller range insted of 1-999 or 0-10,000 TDS. Read the literature on the ways to calibrate it, its worlds different, almost a true lab quality device.
 
The COM-100 has water conductivity and temperature while the HM-4 and 3 don't. I think I will just keep the 4 maybe. I know a really good fish store that uses tap water so at least you have a decent TDS meter to watch the levels.
 
Hey AZDesertRat,

I just recieved my Com100.

2 questions for you:

#1--Which setting do you reccomend, the KCI, 442, or NaCI scale (I think the NaCI scale is most appropriate for seawater EC readings)?

#2--TDS works great for me testing my RO water, but I can't get a reading for EC for my saltwater from my display tank in a small glass dish I rinsed well with RO water.

Is it even possible to use the EC function to check the salinity of your saltwater? I could get an EC reading in very weak saltwater.
I made sure and switched to EC but only get a "---" reading. I did the swirl thing for 5 minutes and even left in the solution for 1 hour. The HM website does not have a trouble shooting section. and they are not open on the weekend.

Any ideas?

Appreciate the help and the reccomendation for this meter over all the others--it has phenomenal accuracy,

James
 
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