why do my water meters lie to me?

I got two of those meters at Home Depot that measure the water, ph, and light and they don't agree with each other. On top of that I usually don't agree with them. Some times they indicate that the soil is dry when it's clearly wet. And sometimes it's the other way around. But they never ever agree with each other.

the best moisture meter is your finger. The pool test pH kits are accurate buy the ones with the red drops and test the runoff to get an accurate reading.

If your talking about those meters that you stick the prong in the soil they lie to you because they are junk & dont work,time after time people try to use that garbage & the results are tyhe same,innacurate readings,you will drown or fry your plants using that garbage,either throw the meters out or get a refund but you'll get no help with your grow using those things.

Instead of relying on junk equipment you should adopt a feel for what your plants need,this cant be done by a meter,for watering you should scarify the top 2 inches of the soil with your fingers,this will let you feel & see the moisture content of the soil plus it helps kill any bug larve that might be in the soil,it helps drastically with wiping out spider mites.

For ph levels you can buy a cheap ph test kit from Walmart or any Petsmart store,you take a sample of the water then add 2 drops of liquid,the water will change color then you match the color to the chart,pretty simple & unless your color blind pretty accurate.

You test the water your feeding the plants using this system & you can test the ph levels of the soil with the same system,simply water the plants until water comes out of the drain holes & collect the run off to measure the ph.