Possible reasons: batteries improperly installed or dead. Possibly keypad is defective. Remedy: reinstall batteries or install new batteries. Replace the pH Testr.

Possible reasons: Keypad is defective.
Remedy: Replace the pH Testr.

Possible reasons: electrode was dry or not properly conditioned. Reference junction is on the verge of clogging up.
Remedy: Pre-soak the electrode before using. Use manufacturer's suggested electrode cleaning solution.

Suggestion: probably at least once every day you use it.

Suggestion: Never use the pH Testr in liquids with high concentrations of heavy metals, sulfides, proteins, oil, or in TRIS buffers; in temperatures above 122°; in solvents known to melt or corrode nylon; or in a slurry where large particles can break the glass pH electrode bulb.

Suggestions: Treated waste water, potable water, boiler feed and cooling tower water, swimming pools, all types of naturally occurring waters (lakes, streams, ground and ocean water), agriculture/ aquaculture /hydroponics chemical applications, water purification processes (R.O. and deionizing), food and beverage water testing, chemical process water, and many more.

Suggestion: If the sticker in the battery compartment shows ink bleeding, the tester had water in it. Look for signs of rust in the tester. Other abuse includes broken pH electrode bulb, cracked casing, and smashing the reference junction plug at the bottom of the pH Testr. Exposure to chemicals listed in item 5 above will cause a black or dark brown stain on the reference junction plug. Technically, this is abuse too. Repeat offenders need to select a pH Testr BNC or pH Wand. with double junction electrode.

Suggestion: El means low battery. E2 means the wrong buffer is selected for calibration (choose pH 4, 7 and/or 10). E2 can also mean the reference electrode and reference junction plug are fouled/contaminated and the pH Testr needs to be replaced. OR means the signal is out of the pH Testr measurement range. Any other error messages are indicative of a pH Testr hardware problem and the pH Testr should be replaced.

Suggestions:
Fresh calibration buffers, pH 7 plus at least one of either pH 4 or pH 10. Electrode storage solution to moisten a piece of paper towel or sponge and place this in the cap to keep the electrode humidified and slow down its drying out. Electrode cleaning solution for weekly soaks to keep electrode in peak performance. Carrying case (belt loop or calibration kit) to protect the pH Testr Lanyard to keep the pH Testr from getting lost Laminated copy of the instructions kept near the point of use for easy reference

Yes, since in most cases these test procedures require resolution and accuracy of 0.1 pH and two point calibrations. Only the pH Testr l is limited to one point calibration and 0.2 pH accuracy. Check the test requirements before selecting the correct pH Testr model. You may need to select the pH Testr 3 or pH Wand for 0.01 pH accuracy with two point calibration.