Since discovering that test kits are pretty crude in providing feedback on water pH, thought I'd look into acquiring a digital pH meter only to discover they are a gazillion of them from <$10 to > $200. Anyone care to suggest a meter? What make & model should I buy? What should I know? What should I avoid?
Found one $109 meter than actually records the last 15 readings and graphs pH tends, but that may be technological overkill. Also appears from doing a bit of reading tonight that I also need to buy a supply of buffer for calibration purposes. Apparently I need at least two and maybe three buffer solutions: 4-7-10. Anyone care to illuminate me on this aspect as well?
pH meters require 2 buffer solutions to calibrate it each time you use the meter. they can be very touchy. So there is the cost of the meter and then the cost of the buffers. You get what you pay for as far as the cost.
pH tests using the test tube and droppers are not so drastically inaccurate but they do require you to compare a test tube color to a card. The dip strips are less accurate.
The meters are not a perfect solution as Raychel points out. There is the initial cost of the meter and making sure you get a quality product that will last more than a few months. Battery replacements, calibration solution replacements, storage solution replacement and replacing the probe every 6-12 months. I had a pH meter I got once that quit working but I didn't realize it until I had already added enough acid to the hydroponic solution to kill the plants. (I'm lucky that was before my discovery of Aquaponics or I would have had a tank full of dead fish too.)
So, consensus so far is... keep using the test kit, which is okay since I like posting the pictures on my facebook page as a sort of visual diary of a new system getting established.
I know the test tubes may see like a PITA but for pH they are really quite easy (fill tube to line, add correct number of drops, shake and read) compared to say the Nitrate tests with all the extra timing and shaking and multiple re-agents.
Speaking of nitrate tests, my API kit didn't come with nitrate re-agents. Came with Phosphate and Nitrite re-agents instead.
Bill it sounds like you may have gotten the pond test kit instead of the Freshwater test kit. I guess for ponds they seem to think phosphate levels lead to more algae blooms and so test for that instead of nitrate. You can pick up just the nitrate test from an aquarium shop or order it online from That pet place so you can see where you are in cycling.
i concur, pens are a major pain, and costly. i had the same luck as TC and put way to much acid before i realized the pen was two points off. the funny thing about calibrating the pen is you have to bench mark it against a test vial. in the long run the pens take way to much time to manage. go with the drops.
I bought a digital pen from Amazon for $8.30 and it matches exactly what I'm reading on my freshwater test kit. I even bought the 7.0 and 4.0 test solutions to calibrate the unit and it's remained spot on for the month I've had it. Personally, I love the convenience although I do occasionally do a sanity check with another test method.