almost giving up on the hobby

[Simons]

by definition, an RO unit should strip everything out of the water. If you are testing your RO water and it has PO4 et al then your RO unit is not working. The only real way to test your RO unit is with a TDS meter. You can get one and put it into your BRS system. If you have anything other than 0.00 then your membrane etc may need replacing.

I have BRS 5 stage 150GPD RO/DI unit with the inline TDS meter, and it is 0.00 before DI and 0.00 after DI. How long have you had your RO unit? if it doesn't have a flush value, the life of the membrane can be substantially reduced with regular use.

I know Calgary's water is relatively hard, on average in my area I have seen it as high as 175ppm before going through a water softener, after my water softener I have 10-20 ppm on the TDS going into my RO unit. However; it sure is 0.00 on the way out.