ro di water

So I might be a bit crazy as someone asked me this today and I really had no other answer then the one I gave. So I have fish tanks and I have my own RO DI water system in which I create my own water for the tanks. I really do not want them to touch tap water as I just don't know what is in it...

I have a Spectrapure 90 gpd unit. I just tested my water with a TDS meter and received a reading of 55 ppm. My question is which filter needs replacing? Or should I just replace them all. Any help would be appreciated.

thank you all for your help with me setting up my RO/DI system. Now my second question is, I have tap water in my tanks, I know.. :-( thats why I bought one finally. Anyways.. should I empty and start over with RO/DI water? Or just take the tap out with water changes?

moving and sold my tank... no longer need my ro/di unit kent maxxima ro/di unit sold the only thing that is left is a 55 gallon blue drum with the locking lid. Asking $20 for it, but open to offers. If you pick up the drum you can also have a bag and a half of salt and a saltwater testing kit...

So I was at Publix today and saw outside the store a Glacier water machine. It is 39 Cents a Gallon. It shows on the front of the machine what filters it goes through before dispensing the water. It goes through about 5 filters I think. One of them being an RO filter and another one...

i am currently using my friend's ro/di water. i do not want to bother him so i want to get my own water. i am not planning to buy a ro/di system because it is pretty expensive. i see ro systemed water vendor machines at shopping plazas where people get drinking water (5 gallon) from. is this...

i am currently using my friends ro/di filtered water. i do not want to keep bothering him. i see ro water vendor machines at shopping plazas. this water is used for human consumption. is this water reef safe?

I currently do not have a ro/di filter installed for my tap water. I have to keep asking my friend for water because he does have a ro/di filter. here is my question, if you guys notice, at some plazas (shopping centers) there are water vendor machines where you stick a 5 gallon water container...