Why you need them and what to look out for!
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Meter’s are definitely a topic of discussion in nearly every forum that has hydroponics groups. From Facebook to Twitter, meters are a point of contention between many growers.
The reason for this is generally quality and the ease of use. The main point of contention even between experienced growers is the quality of any given specific meter. There are many myths and truths about meters, and I’m here to give my opinion on the topic. I want people to grow in hydroponics because we sell systems. I also understand how expensive it is for people to get into hydroponics at the begging. There are lights to buy, nutrients, systems and of course meters.
Out of the Box
I use test solutions to check my meters. For instance, I know my tap water is running a pH of 7.3 to 7.5 on a pH meter. By saving some tap water in a jar that I have taken a good reading on, I will have a means of spot testing my meter later. This will allow me to quickly confirm it’s still reading accurately. I can mark the jar with the verified pH and use it as a test solution to check my calibration periodically.
I can verify this to a point with a test solution. The best way to create a test solution is to use the solution powder that comes with most meters. First, however, I highly recommend that you calibrate a new meter. They have been tossed around during shipping and need to be calibrated out of the box. If you’re not sure how to calibrate your meter or would like to see the process before you do it, there are plenty of videos online that will show you how. Always verify the process by following the instructions included with your pH meter.
I use some 1-pint mason jars to store those solutions in a dark place then reuse them. I only do this after I verify they are still in the correct range. If they are not, then toss them out and mix a new solution before calibrating. Another use for these solutions is to test whether or not your meter needs to be calibrated.
Cheap Meters are useless or stink? Not really…
This is far from the truth. Cheap meters require a little more care and have a learning curve. Most are very similar until you get to the upper-quality range. The difference between 2 cheap meters and 2 of Hanna’s low-end meters, one for pH and one for TDS, is the Hanna’s will cost you around $60.00. They are good meters with some nice features. With the cheap meters, you can buy a set for around $20.00, sometimes less. That’s a third of the cost, and if you’re new, you will probably look to trim the costs of setting up a system.
Cheap meters require a few things. First, read the directions, so you know how to properly read the meter. For instance, cheaper meters will read differently than higher-end meters. Many of these meters will read EC like this 1200 and ppm like this 600. The EC reading does not display the decimal point after the first number. So an EC reading of 1200 is actually an EC of 1.2 or 600 PPM. I suspect one of the reasons for this is they didn’t have to change the design of the LED screen to show the decimal point.
Key features you want on cheaper meters.
A four-digit LED Display. Some of the very cheap meters will have only 3 digits on the screen of their TDS meters. When you reach 999 PPM, it will convert to x10 or just not display the 1 after you are at the 1000 PPM mark. This I don’t like. It just increases the difficulty of reading the meters. Fortunately, this isn’t very common but keep an eye out for it when purchasing your TDS meter. So take a good look at the description and see how the display is set up. The savings is so small it’s not worth it in this case.
Back Lighting. I like at least my pH meter to have backlighting. I have both, and when I check pH at night when the lights are off, it’s easier to read. Many TDS meters do not have backlighting even when the pH meter does when buying sets. I usually test TDS once a day and pH twice.
The Margin of Error. Most meters operate the same, but the margin of error is a key feature to be aware of. Most lower meters seem to fall into the +/- .02% range. Do not buy a meter unless you know the margin of error.
All meters require maintenance event the high-end meters. When using cheaper meters, it’s even more important. Don’t drop them, rinse them off regularly, and don’t allow nutrient solutions to dry to the meter probes. These are good rules for every kind of meter. I keep a small freshwater container around to rinse my meters off at the end of every day.
So yes, there is more to do with cheap meters and more precautions such as regular tests and cleaning.
The last thing I will mention is batteries. I see many problems that look to be related to batteries online in the hydroponics groups. If your meter starts freaking out, the first thing I would check is the batteries. Cheap meters come with cheaper batteries. Replace the batteries with a really good set, and you will be surprised at how well your meters will maintain their accuracy.
Most of the cheap meters take the LR44/76A 1.5v Battery. Check your battery type by pulling the batteries and reading the type before you order.
High-end meters come at a price, but they do provide a sense of security and confidence in the meter that you may not find when using the cheaper meters. Many people have a hard time trusting their meters or accepting that they can vary in readings. Low-end meters do not adjust to nutrient temperatures as well and require some maintenance to keep in good working order. This is the driving force for people to spend money on higher-end meters.
Any meter is better than no meter, and caring for your meters is an important aspect of maintaining your hydroponics systems. This isn’t about keeping up with the Jones’s. This is about finding a functioning meter that will get the job done in your price range.