Nutrafin Tests and Brackish Water

[TheSilentPerogy]

Ever since the horrible death of my Figure 8, I've been keeping the tank cycled by adding in 6 drops of pure ammonia daily (15 gallon tank). However, even while the puffer was in the tank and I was sure it was fully cycled, I had a minute Nitrite reading on my Nutrafin test (~1ppm) even though nitrates were present (~5ppm).
So, while keeping my tank cycled, this small presence of nitrite has remained. Finally, to test out which was giving me a false positive, I added in ~5ppm of ammonia. The next day, the nitrite spiked (>5ppm) and went down over a period of 3 days back to ~1ppm where it's stayed.
I also bought a high-end pH test kit by Nutrafin, since the water in this area is generally on the more basic end of things (ph ~7.7) and so I can ensure my puffer's tank is more basic than typical.
The scale on the high-end pH test kit goes from green for 7.4 to blue for 8.6. I add in the water and the reagent and compare it to the chart, but there is no 'black' to compare it to. My other tanks all tested around 7.7, as expected, but after many tries and washings of the test tube, the color from the puffer tank (at 1.005 sg) always turned black. My brought-range pH test kit accurately puts the water at 8.0-8.5 though (LFS tested it a while back at 8.2).
So I finally got the idea to test out these tests on pre-mixed salt water. Despite all the tests saying they are good for fresh and salt water, the premixed salt water tested 1ppm for Nitrite, 0 for Nitrate, and turned black for the pH test kit.
The brand of salt I use is Red Sea, a brand used by the Canadian chain Petcetera for their marine tanks (I'll be switching to Instant Ocean when this runs out as I've found it much cheaper elsewhere).
So...to summarize: does anybody with a brackish tank have Nutrafin test kits and have similar problems?

[PetPirate]

I had a similar problem... also used the Nutrafin test. Truth is: It showed a tiiinnyyy amount of nitrite all the time, until the tank *really* became established -- more water flow, better filtration.

Another problem I had was with my tap water containing nitrite, but that's another story.

[TheSilentPerogy]

Very strange.
Fortunately, my tap water comes clean as a whistle (0/0/0 all around).
I'll probably end up buying a different test kit (ugh, probably strips; all they sell around here are strips and Nutrafin liquid tests).
Thanks for the info!

[YBeNormal]

If you cannot buy quality test kits in your area, you might want to consider mail order or have a friend in another area mail one to you.

Test strips might be OK for quick checks but they are notorious for being inaccurate. I use them for quick checks of my swimming pool but I still use drip kits at least once or twice per week just to be sure. I don't and would not use them for testing my fish tanks. JMHO

[PetPirate]

What filter / media do you have?

[TheSilentPerogy]

I'm running an Aquaclear 200 with a filter sponge, filter floss and ceramic Biomax beads.