Re-reading my post, seems I might not have been all that clear about the claibration solutions. If you can't afford both the calib. solution and the electrode storage stuff, the pen's instructions say that the 4.01 calib. solution can be used for electrode storage, too. (in case other members are in the same boat)

Might want to get the electrode (the LED looking thing) into water at the very least, and let it soak overnight before use, however white or brown vinegar lasts longer, and it doesn't let algae grow. Not sure it will help now, though.

You might want to take it to an aquarium store to see if they can determine it's accuracy for ya in both the saltwater (8.3 ph) and freshwater tanks, (7.0 ph) if they keep their tanks right on the money. Accuracy within a point or two is still workable, but keep in mind the difference when actually using it, and look for any wild/unusual ph swings. (don't trust it too much, lol)