Yeah ph the nute solution after everything thats going in the water is in there... Nutes will lots of time lower your pH, or raise, depending on with nute system.
& Just a note.. I don't use clearex or anything and my plants are fine.. I don't really know whats in that stuff but i've just generally found the less unnecessary stuff the better... Not hating on those products just saying don't get dependent, as they can sometimes make stuff worse! ;D I just water with plain balanced water, and figure any dissolved salts will either get washed out or taken up by the plant.. Healthier on the beneficial bacteria in the soil too.
Think about investing in a hannah meter, the $40 that goes to .01 instead of the $20 that goes to .1 .......... With that one you can calibrate it better, and it's a lot better of a probe.. Also, you can replace the probe in the future (half the unit) for $20 and make it function like brand new. I've already done that once and I've had it for years, works great.
Are you using any CalMag?