Best Water Testing Kit

[renman303]

Two questions:

First, how do you know if your testing kit is still working properly? I have a number of kits, and for example, I was testing Phosphates. I have 2 API kits and they both read different readings...completely different! I also have an Aquarium Systems Kit by Instant Ocean. It reads differently as well. Now, here is the weird part. the color sample cards that came in the API kits are completely different in shades! Had I not had the second test kit, I would have never have known. I have attached two pictures. The sample card on the left came from the large API Masters Kit. The two cards on the left came with the single API Phosphate Test. Looks to me like the masters kit has the wrong card in it? Or are the ones in the single kit backwards? Maybe buying a testing kit isn't worth it and I should spend $50 on each electronic tester like Phosphate, Nitrate, pH, and Ka?

Second, how do you know when these kits or the chemicals have expired? Not one kit that I have has a manufactures date of exp. date on the box? These could have been sitting in a store for years!

Any recommendations would be appreciated!

[FarmerTy]

Looks like they may have accidentally printed the freshwater colors on a saltwater card.

Either way, API is rubbish to me as a test kit. You're safer going with Red Sea Pro or Salifert. I've never used Salifert myself but they have good reputations. I like the Red Sea test kits because they are titration-based, more accurate in my opinion though user error could introduce some bias.

If it were me, I'd get Hanna meters for alk and phosphate, then Red Sea for nitrate, calcium, and magnesium. Those tests alone should give you enough of a base for any tank.

[renman303]

Thanks, good info. I'm tossing these kits in the trash as they are a few years old anyway not including shelf time at the LFS.

[Timfish]

I'd have to agree with Ty about your cards but manufacturers may make changes to the reagents and would need to change the color chips or cards so always use the card that came with a kit. Irregardless of any expiration date (if any) I always replace test kits yearly. I also do a side by side comparison of the old kit and new kit to see if there's any differences. I personally like API for pH, calcium and alkalinity but use Elos for low range phosphate and Nylos and Red Sea for nitrates. Here's a link and a .pdf on some comparison tests between manufacturers:

http://www.advancedaquarist.com/2012/6/chemistry

DFMAS TestKitAnalysis.pdf