color-matching versus numerical water tests.

Sk8r

Staff member
RC Mod
I've studied art for years, and *I* don't trust my ability to color-match. I can give you some hints: set the test vial on a white surface and under a 'white' light, as opposed to yellow. Then look for the general color tone, ie, is it a pure blue or is it greenish or toward the red.

Personally, I opt for numerical tests: Salifert: you prepare a vial of solution from the tank water, fill a syringe with a solution from a bottle and shoot it into the vial. At a certain point, the solution will begin to 'flash' a new color as the syringe-stuff goes in; that's your warning you're approaching the change point. The change when it comes is quick, and often changes the opacity of the water, so even people who have some color blindness might be able to spot the change. There's no matching. You look at the barrel of the syringe at that point, note where the business-side of the plunger is stopped right now, say 4.5, and you look at your chart and find that 4.5 on the syringe equals an alkalinity of 8.3. (or not: I don't carry these numbers in my head.)

The Salifert No3 tests, etc, DO use color matching, but I still find them a bit easier to figure.

A refractometer also renders precise numerical results in salinity.

And bear in mind---write the date of purchase on your test kit---and do not expect these kits to last for years and years. If you get a bizarre result, the first thing to be sure of is that your test kit is not expired, because they do expire: chasing numbers from an expired kit can lead bad places. I'd replace a kit after a couple of years, say, on general principles.

Most needed test kits: nitrate and alkalinity. Nitrate under 10 if at all possible and alk between 7.9 and 9. (Alk is related to ph, but is a better measure of water conditions.) I shoot for 8.3 alk as a nice middling reading.
If you have clams, or stony corals (hard skeleton) you also track calcium and magnesium. Calcium is good at 420 and magnesium is good at 1350. If your magnesium falls lower than 1200, your alkalinity will start sinking like a stone.

There may be other brands out there that also render numbers...whatever you can find is likely good. But the point is simply that 'numerical' tests are definitive, and a lot more helpful in the finesses of tank management than 'kinda pink.'
 
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I've studied art for years, and *I* don't trust my ability to color-match. I can give you some hints: set the test vial on a white surface and under a 'white' light, as opposed to yellow. Then look for the general color tone, ie, is it a pure blue or is it greenish or toward the red.

too true.

Any thoughts/experiences with RedSea Reef Pro Kit for Ca/Mg/KH? I like it, but have had throw out and restart a test before when I got funny results.
 
Red sea kits is ok, the one test I dislike is their alk test, the color change is very slight and I'm never sure when to measure (when it starts to turn, when it's fully turned, etc) ca and mg are are more quick and obvious change in my opinion. May give Salifert a try when my current batch is exhausted.

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The Red Sea pro stuff is pretty good. I use it for calcium/mag and the basics (ammonia/ph/nitrate) when needed. I do like the Hanna digital/numeric checkers for the stuff I test more regularly (Alk, phosphate.) And you can't really go wrong with the Milwaukee digital refractometer for testing salinity.
 
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