RODI Machine Issues

[franktobia]

I bought an AquaticLife Twist-In 4 Stage RODI Unit and it has been very inconsistent when using it for weekly water changes. I have had it for about 2 months and the TDS reading is different every week. Some weeks I will get 2-5 ppm and others I will get close to 60 ppm. Am I supposed to use the included flushing cap every week before and after each use? The directions made it seem like I was supposed to flush for 30 minutes before the first use and then i would never need to flush again.

I’m currently sitting in my room with a bucket of rodi water with 57 ppm which does not seem safe at all for the fish. I’m not sure if this would throw off the reading from my TDS meter but there was some sand and salt crystals from my last water change sitting at the bottom.

 

[Sniperhank]

You only need to use the flush cap with a new carbon filter.
As for the tds, this stands for total dissolved solids. It should t be affected by sand, but I’d put money you are now picking up the extra salt that was in the bucket.
I’d suggest having a different bucket solely for water if you don’t have an in line tds meter.