Adam E
Member
Hi all. Got a little issue I'm struggling to get my head around. Every time I use a tds pen on my aquarium I get different reading(like 20 mins apart). Basically I let my tank slip whilst I was working 7 days a week and the tds when i checked was 867ppm. My tap water is anywhere between 250 and 350ppm( varies on how long i run the tap prior to filling the bucket) so I've been doing partial water changes every 3 days and the tank is now at roughly 450ppm. I went todo a water change today and when i tested the water it said 457ppm. I took 15ltrs out and put 15ltr of tap water into a bucket at 270 ppm with de-chlorinater which increased the reading to 301ppm. I let the bucket sit with a heater for 30 mins to get it to tank temp. I then tested the water again and it said 390ppm?? So I then tested the tank before adding the 15ltrs back in and it's now saying 527ppm? So I cleaned the pen by running under water. Tested tap water and it cam up at 268ppm. Then tested the bucket and it said 315ppm, done another test on tank and it's now at 370ppm? Is there something I'm.not taking into account or is it just a dodgy pen? Sorry for the long winded post. Just trying to explain as good as I can