Question 1

I have purchased 2 of these, why are they so inaccurate?

Accepted Answer

If you calibrate ANY PH meter using the mix it yourself "calibration" solutions, accuracy will be impossible. I just purchased this meter set, and discovered the distilled water I use was ph4 and below! I have the "other" style cheap meter, that has proven very stable for me, and after checking it in GHP 7.0 calibration solution, used it to test the accuracy of this relentlessly poor example of a ph testing system. 
First off, the solution instructions make no mention what the ph of the distilled water needs to be. My 4.0 water mixed with the 4.0 and 6.86 powder, resulted in a solution of 3.3 and 6.0 instead, so IMO, the MIY calibration solutions are a joke, as are ph meters that calibrate on the 6.86 standard instead of 7.0.

Question 2

If i use a 7.0 calibration solution will the automatic calibration be off by .14 since it comes with a 6.86 calibratind powder?

Accepted Answer

Yes! I recently calibrated with 7.0. Prior to calibration, it read the 7.0 solution at 7.0, calibrated with 7.0 solution it now reads 7.18. Find the correct calibration solution

Question 3

If my tap water is between 6.5 and 7.0 ph do i need to add the ph up and down liquid i bought for indoor cannabis grow? What about ppm?

Accepted Answer

If you’re growing in soil 6.5 is perfect if you’re growing in Hydro/water do you want to be around 5.8 say you’re at 7.0 PH I would just add a couple drops per gallonTo get it down two around 6.5

Question 4

If I choose EC, does it retain the setting after power cycles?

Accepted Answer

Yes, but my meter randomly switched back to TDS.  The "EC" does not show a decimal, and the numbers are too close to TDS. If you don't pay attention, you will hurt your plants.

Do not purchase.

ASIN	B01DNUIGUY
Batteries Required?	No
Batteries included?	No
Best Sellers Rank	51,947 in Garden ( See Top 100 in Garden ) 77 in Soil Meters
Colour	soil tester
Customer Reviews	4.0 4.0 out of 5 stars (10,140)
Date First Available	31 Mar. 2016
Guaranteed software updates until	unknown
Item Package Quantity	1
Item Weight	90 g
Item model number	4316237907
Manufacturer	VIVOSUN
Material	stone
Package Dimensions	32.9 x 10 x 4.1 cm; 90 g
Part number	4316237907
Size	Soil Tester

VIVOSUN Soil Tester, 3-in-1 Plant Moisture Meter Light and PH Tester

Details

Details

Description

Specifications

Common Questions