Trident advice

[Lzippy]

Not sure if this is the right spot so sorry if not. I picked up an apex and trident around a month or so ago. I let it run normally for 3 days before calibrating the trident and since then my numbers just seem to jump all over the place. My alk test is the only one that stays mostly stable and closest to match my manual testing. It is installed on a Red Sea max nano xxl all in one tank. Does anyone have any advice on this? I have checked for air in the tubes, kinks in any of the lines, I did not shorten or lengthen the sample tube or the waste tube. I have moved the the sample hose to a few different locations trying to see if that would make a difference and I also have the sample tube filter installed on the end.