I've used plenty of test kits over the years and always question their accuracy as well. I started using the Seachem test kits recently and the ones I've used come with a reference value. It make it a little easier to guage the colour especially if you put the reference value beside the tank sample.

Overall, test kits are a pain in the #@%!! A necessary evil.

I'm going to give the Seachem ones a shot. I have to laugh because depending on my light conditions the nitrate in my tank is either at zero or everything in my tank should be dead :lol:

I always used to swear by Seachem because of the reference value. I wish all testkits came with one, it's a brilliant and simple solution to answering the question "how do I know this test kit isn't fubar'd?" .. I had to stop using Seachem a few years ago though because they changed reagents and the colour shifts on their titration kits became near impossible to discern the change (the change went from "clear, with a slight pink hue" to "clear, with a slight blue hue" whereas before it was a clear shift from pink to blue. If they've cleared this up I'm switching back to Seachem.) I've since bounced between Elos and Salifert and while they're not bad, they're not great. Suffice it to say, any test kit has its pluses and minuses, so pick your favourite. As stated, they are all PITA's but necessary evils.

And yeah, having two brands of test kits onhand has been a real eye opener in terms of precision and consistency (ie., too wildly different readings, whom to believe?). Reference samples would totally clear that question up...

Found Salifert to be great, Tropic marine is pretty good.