PPM Pen... Stumped

so i am stumped..

i mixed up my nutes for about 35 gallons and i added

GH Micro 275 ml
GH Bloom 550 ml
GH Floralicious Bloom 150ml
Calmag Plus 50ml
Silica Blast 50ml
Advanced Big Bud Powder 9tsp

now here is the weird part.. i let it mix up for about 20 minutes in my big rubbermaid trash can with a pump and airstone at the bottom (mixes very well) and then proceeded to test it with my tds pen.. which it came out to about 1250 ppms which seems about right to me, phd it and came out to about 5.2

now i added it to my res (fresh change) and let it run through for about an hour... here is the weird part, i came back and tested the ph again, still about 5.2, but it said my ppms was 750? i am totally stumped..

so i start thinking back to exactly what i mixed up thinking i forgot something, but i know exactly what i added.. it would be wierd for my meter to just to flip out like that.. anyone had any similar experiences?

i am not too worried about it cuz i am pretty sure i mixed it up right but didnt know why it would do that.. if it makes a diff it is a sunleaves meter

i guess i will go get some calibration solution tommorrow and test it out..

FLo

i also should mention that i ran the contacts under warm water to try and wash off the excess salts.. i am wondering if it is shot since i accidently dropped it and water and may have got some on the board.. i donno but just wanted to add that