TDS Meters Must Be Used Correctly.

TDS meters can kill shrimp and fish if you don’t know how to use them correctly.

I want to talk about TDS meters. I interact with you guys a lot. The more I interact, the more I feel like the majority of people using a TDS meter aren’t getting all they can out of one. It’s because TDS meters are awesome. They’re super easy. Basically, you stick them in the water, and they’ll give you back a number. Awesome. You can use them a million times. You get the reading in a second. We’re putting blind faith into this, I think.

The problem with a TDS meter is it measures total dissolved solids, so everything. Minerals, salts, nitrites, nitrates, ammonia. Things that we use in the aquarium like, let’s say, aloe vera from dechlorinator. Let’s say, fertilizers, the excess poop. All those things. It’s all going to come out as just a number. The problem is without other information, that number means nothing. I’m going to demonstrate that to you. Let me get setup, and we’ll hop to it. For this lesson today, we’re going to use my wife’s planted tank, which has turned into a jungle again. Definitely no shortage of plants and wisteria in there for sure. We’re going to use this aquarium. We’re going to use this right here. This is a group of water with salt in it. We’ve got tap water, and we’ve got tap water. We’re going to do some things with this tap water, and we’re going to do some tests here. The first thing, let’s get a baseline on my tap water. My tap water . . . Let’s see if we can get some light on this. Well, I’ll just read it to you. It is 26 right now. So 26. It doesn’t tell us 26 of what parts per million, but what’s in my water? We don’t really know. There’s not a whole heck of a lot, honestly, and that’s why I have to add additives to it. Over here in my aquarium, we can also test this. Just that quick. We can see I have 187 parts per million of something in there.

TDS meter and pH meter comboWe also don’t know what that is because this just gives us a number. Then we have this salt that’s in here. We’re going to test that. We put one tablespoon of salt in this thing, and we have a TDS of 886. So those are just numbers. They don’t mean a whole lot because they’re not telling us anything other than that’sa number. What we can also do in this one right here, we’re going to add fertilizer. Let’s say this is your aquarium, you have plants you need to fertilize, and we’ll put a couple of squirts in there. Now I’ve got to stir it. We were at 26 earlier, I believe. In theory, we should be higher now because we’ve added stuff to the water. With two squirts, we are at 579. Hold on. Let me get that little more mixed up in there. We’re at 435. So by adding fertilizer, our TDS has now changed. If I get this a little bit clean again. This is our tap water. We’re at 28 right now. So by adding fertilizer, we’ve established we’ve raised TDS. Let’s add some dechlorinator. This has a little bit of Stress Coat in it and stuff like that.

So if you’re using API Stress Coat, if you’re using Prime, it’s going to do the same thing. We’re adding chemicals to water. We’ve added some, and you can kind of see the swirling in there because we’ve added chemicals to water. Once again, let’s give it a quick stir, and then we’ll test. Grab the TDS meter, plop it right in. We now have a TDS of 184. So if we added a little bit more dechlorinator in there, technically, the internet would say “Oh, that’s ready for shrimp because it’s got enough TDS,” or “That livebearer wants this,” or “discus wants below that.” So those don’t tell the whole story. If we start adding, let’s say, another test kit to this, it can start making a lot of sense. It can start helping us out. Let me grab a test strip here. We’re going to do this for sake of time and ease, and I’ll make a video on why I like test strips and stuff like that. We’re going to dip it straight into the one with salt, and we’re going to compare it here. When you look at this kit, you’re going to see that essentially it’s got no nitrates in it, no nitrite, the hardness is up a little bit, no buffering capacity. Because that’s what salt does, it adds usually to the hardening a little bit. So we’ve hardened the water a little bit. Now, this one right here, we put fertilizer in. We put my Easy Green in there, and I know it’s got nitrogen in it to grow plants and other things. Let’s test that.

We’re going to let that sit for a moment here. It’s just starting to turn pink, so that’s the nitrogen that’s in there. Now, we still know with the test kit, oh, we’ve got nitrogen in there. Then we put in just some API water conditionerdechlorinator and stuff, and I would bet you this is just going to look like my normal tap water here because I don’t think it’s going to have anything we can really register. So now we’ve got parameters, but we also have meters. That’s where you can see this meter didn’t really tell us anything. It can. If we just did a water change on here, and we wanted to put fertilizer back in, we can help make sure we didn’t put too much in. Same with dechlorinator. Also, in my fish room, if I have a bunch of tanks, and I go and measure 50 of them, and three of them have a way high TDS, it means, hey, come back and test these and figure out what’s going wrong. Likewise, we looked at my water here, and it only had 185 TDS, but that doesn’t tell us a whole lot. What if we were to test that water? Alright, we’re going to throw a test strip in there for ease. Now we might be able to figure out, okay, we have 185 parts per million, but of what? What’s in there? The reality is not a lot of nitrogen at all, so the water’s very clean. I need to put more fertilizer in. The water’s decently hard. We have good buffering and good pH. But as far as this goes, this tank’s clean as a whistle.

This tank now has gone two months without ever having a water change. You guys have been watching it. I’ve been growing lots of plants. We’ve been fertilizing with Easy Green. But no water changes. The important part of this conversation is that a TDS meter doesn’t mean anything without some result. I have a baseline. I know that at 185 TDS in this tank, going for months and not changing water, that it’s going to be low on fertilizer. Now, in theory, I need to put . . . This is a 230-gallon tank. I need to put 23 pumps in there to fertilize it for the week. One, two, three. We’re going to speed this up here.

Six and a half hours later. Given sufficient time to mix and stuff like that, which I’m not, but ifI had. Yeah, right now it’s saying there’s 220, 200 . . . It’s diluting a little bit because it’s. . . We’re 200 parts per million at the moment. That would help us know how much fertilizer am I running out on? But it doesn’t give us precise things. It only tells us a number. For instance, if I go into my fish room, and I have 200 TDS here, and I have 200 TDS in another tank, that doesn’t mean they’re running the same at all. I could have salt in one. For instance, here we have my fertilizer, and we’ve got 345 TDS. If I pour a little bit of this salt water in there. Just like that, just a little bit. Let’s say that was fish poop or whatever it is. When I go back to test this. What do you mean it’s 534? So it doesn’t tell us what’s in there, and that’s the hardest part about the TDS meter.

Here we have two different shrimp tanks. I have blue velvet shrimp in here, and it’s a colony. They’re breeding. There’s babies. That type of thing you guys have seen in my fish room. Over here, we have a colony of Cherry shrimp cherry shrimp, and there’s lots of babies all over the place. We’ve also got fireball platies in there as well. Remember, websites are saying 120 to 250 TDS. I’m going to turn my meter on, we’re going to stick it right in here, 48 TDS is all we have. Yet, my shrimp are thriving and producing. Let’s look at this tank over here. Once again, get it under the light, 43 TDS. Okay. So that right there . . . Yeah, now we have a number, but it just goes to show that the number itself doesn’t tell us anything. We don’t know how much hardness I have or anything like that. We still need to use test kits to determine that. I know that I’ve got a little bit of crushed coral in here and things like that, but in general, my shrimp have always thrived in the TDS that I run. I don’t change it.

I find a lot of people run into trouble or think they can’t keep it because they can’t get their water parameters right. The reality is, there’s a lot of things going on. I just wanted to clue in on my shrimp. Also, let’s look at one more tank. Here we have a 40 breeder. Obviously lots of panda guppies in here, lots of fry, lots of shrimp. I breed lots of shrimp. There’s also plecos breeding in here. I’ve never tested this water for TDS. So let’s take a look at that real quick. I can see that we’re at 76 TDS in this tank. So right there, I’m still way less than any of the shrimp websites are saying that I could possibly be successful with. Yet, I’m running into no problems at all, and it works well for me.

Now, I’m not going to say that having close parameters to what a breeder is using isn’t helpful. The problem is when people drop all the other parameters I listed when I was talking about those shrimp and just go by the TDS, that’s the problem. When they start not worrying about pH test meterpH, they start not worrying about hardness, or calcium or magnesium in the water. Things like that. And they just straight up go with this number. This number is nondescript. It doesn’t tell us how much of any one thing. It tells us of all the things in this aquarium that are dissolved in that water. It has that many of these things. So I get it. You basically don’t know what to do with the TDS meter now. They are useful. I do use them. I own like four of these between the store and home. The best way to use them is to calibrate something that you’re trying to up. For instance, let’s say you had a guppy tank or a shrimp tank, and you wanted to add more minerals. You can figure out your baseline, and then you can add some minerals to it. Then, when it comes time to do a water change, or let’s say it’s been a month and you want to know how many minerals are left in the water, you can use this to help you guess. Now, yes, is a test kit generally an easier way? Yes, but what I love about this, this is how I solve a lot of unknown problems. Because this will test for anything, it will pick up things that the test kit won’t. For instance, sometimes people come into my store, and I cannot figure out why live plants won’t live. If I can pick something up on here, then I know there’s something in your water. I can’t tell you what it is. A lot of times, it turns out it’s like a water softener because they’re on a well or something like that. Or let’s say that the fish didn’t do well, and I can’t figure out why. Then you test it, and you’re like, “Well, your TDS is through the roof. You’ve got over 1,000, and our water here in the store or at home only has 100. There’s something in that water, whether it’s lead or copper, or it’s just nitrates. “We would’ve tested that with a kit. But that’s what you get to use this for.

So I find it really useful when you own a lot of tanks. If you own a ton of tanks, let’s say you own 10 tanks, and you just want to see how they’re going, and you track the TDS on the tank, you can know, oh, man, my fish are really spawning well, and babies are raising fast, and I never had disease as long as I keep it around 200 parts per million with this amount of water change schedule, with this amount of food, those types of things. And if you go to 350, and you notice your fish are getting sick, then you know, okay,when this gets above 250, I’m going to change water. The hypothesis or the educated guess would be that, for instance, nitrates are rising or something like that, so you’re combating that. But we can’t know. Just like in this tank back here, clearly it’s got more stuff in it than my tap water. It was basically out of nitrogen. It could just have remnants of dechlorinator from the very first time I did it. It could be amounts of copper. It could just be what they call in the koi world the DOCs, dissolved organic compounds, that we can’t test for in a kit.

The koi world’s very conscious of DOCs, and in the aquarium world, it’s like we treat them like they don’t even exist. If you enjoyed the video, go ahead and give it a thumbs up. If you want a TDS meter, buy one with the link below to the page on Amazon, that’ll get you one. You can start playing with it. I do use them about weekly or so just to tune in on some stuff. If I’m really trying to breed something, I’ll use it. Or if I’m working with unknown water, it works just as well.  TDS meters on Amazon