Having trouble testing run off PPM

Hey guys as the title says I'm having trouble getting a accurate reading because it's geting contaminated by the little bits of coco that come with the water I've tried to try skim some off the top with the syringe but even then you can see tiny little bits of it, currently in plastic pots gonna use a fabric one for flowering so should be alot eaiser untill then tho anyone got any idea's how I can get some clean water to test?

if you absolutely want to test it, lift a pot during the irrigation session and recover the runoff

if you want to avoid the necessity to measure it, give big runoff everytime you water the plants
this way you are keeping the medium free of accumulated salts, and you reset the pH/EC of your medium everytime you water

the rule of 10 %/20 % not always apply and give a bigger runoff is a guarantee of proper pH/EC monitoring

if you water enough everytime you get
feed EC/pH= unoff EC/pH

Cheers for the reply glad i did this tho was testing at 2000 PPM for a 2 week plant was dealing with it pretty well although i'm really unsure how those numbers came about i've never not let it run off my other plant who's 2 week's older is coming out 100 ppm less than i'm putting in and i feed in exactly the same manner strange but it's sorted now just flushed it run off is coming out at 250 now