I was looking to replace my aging API nitrate/phosphate test kits with something nicer.
The Red Sea kits caught my eye because they're reputed to be easier to read. Instead of holding a vial up to a test card, you fill two
vials, and insert them into a gadget with a rotating color wheel.
The first vial is filled with tank water and test reagents. The second is filled with tank water only. You then insert both into the gadget, and rotate the wheel until the color as viewed through vial #2 matches the color in vial #1. This is supposed to make it easier to match, and the dual vials compensate for any color your tank water might have.
So I purchased both as a bundle, as an "Algae Control Test Kit"; which at $50, is cheaper than buying both nitrate and phosphate tests individually. But at that price, it should perform better than API tests.
The first test I tried was phosphate.
: Each vial has to be filled with 16ml of tank water, which must be measured since there is no fill line. They give you a syringe to measure the water. The problem is that the syringe is only marked up to 10ml. So you end up measuring 10ml, then 6ml (or some similar method) to fill a single vial. Repeat for the second vial. That's four measurements. But these tests are by default low-range, appropriate for marine tanks. High range tests are possible, and detailed in the instructions; for these it's suggested you use 1ml of tank water, and 15ml of distilled water. So that's three measurements per vial, and SIX total! Compare that to the API test where you just fill a single vial to a fill line... fail
: Similar to API's test, you add drops from two reagent bottles. But unlike API's test, the number of drops from each bottle is different. That adds needless complexity, so again fail
: API's test takes three minutes. Red Sea's takes six. Fail
: Here's where the payoff should be. For all this extra trouble, the colors should be easier to match. But I didn't find them any easier to match than API's test card. And holding a vial up to API's test card is easier than opening the gadget, flipping the wheel to the right side (nitrates on one side, phosphates on the other), latching it closed again, and rotating the wheel. Furthermore, my tank water didn't have any detectable color which might have skewed the result, so the dual vial system was pointless. The gadget is just a gimmick, so fail
Then I moved on to the nitrate test. It has all the disadvantages of the phosphate test, plus you have three test reagents instead of API's two.
But it was very
hard to squeeze drops out of the first bottle. And the high range test read zero
on my tank water.
I spend the next hour trying a low range test, various KNO3 reference solutions, even saturated liquid KNO3 solution. All read zero
So I called Red Sea. They referred me via email to their test kit expert. He was helpful and knowledgeable. He explained that the first reagent bottle contains gray, solid granules in liquid, and must be shaken thoroughly before use to disperse the granules. But in this case the dropper was mostly clogged, and was probably not letting the granules pass; so it needed to be cleared with a needle.
Doing this solved the dispensing problem, but after more than another hour of running tests and widening the opening with successively larger needles, all still read zero. And the granules were nowhere to be seen.
He then sent replacement reagents, for free. Good customer service, at least. This dropper worked. And the granules were clearly visible, showing that there was a defect in the original reagent. But again it failed to register any nitrate under my battery of tests.
At this point, both my patience and the 30-day return period had almost expired. So I bothered myself with it no more, and returned it for a refund.
While it would have been nice to figure out what the problem was, I'd still have a test kit that was more expensive, harder to use, and ultimately no more accurate than API's. For the same price, you can get a bunch of API test kits. Or Hanna's electronic phosphate "egg" colorimeter, that will give some very accurate results on a digital display.
To sum up... I do not recommend the Red Sea Nitrate/Phosphate Pro test kits.