rodi water

So I was gonna buy a 10" standard RODI Unit but it's like $300 brand new (CAD), but I seen on my local classifieds that someone has a 4 stage (or I think it's actually a 5 stage) for under $100 (CAD) but unsure of the brand (seems like it has no name), but the person said it's practically new...

So in a continued effort to understand what's in my City Water and what poses a potential risk and would need to be filtered and treated for a tank (Fish Only With Inverts), I found my local plant water quality report, and am curious from others who have more knowledge than me, how good (or bad)...

I only just got a TDS meter after making about 150-200 Gallons of RO Water with the “Aquatic Life RO Buddie Three Stage Reverse Osmosis, 100-Gallon”. My tap water is reading 70ppm on the TDS and my RO is reading 4ppm. I know 0 is ideal, but does 4 mean I’ve burnt through the filters already...

Hi all. I am trying to prepare a freshwater dip for my seahorses and can't find a "recipe" for how to raise the pH in the rodi water, using bicarbonate soda. Could you please tell me how to do this? How long after you have added and mixed the bicarb to the water should the levels test...

My Question is it ok to top off with RODI Water during Cycling since I’ve noticed some evaporation? I just want to make sure so I don’t ruin or mess the progress of the cycle with my Ammonia dropping to 0.25 and the cycling is coming along the Nitrites up to 5.0 and Nitrates starting to build...