Those readings make a lot more sense. @DaveKS
, I think we were replying at the same time - itís a good point on the high probability to get whacky readings with pure water. But @RollaPrime
said he forgot to remove the membrane before flushing the system so better safe than sorry.
I'm not sure if I should adjust the PH to be closer to my tap or if I should do small WCs over the course of a few days seeing as I plan to use RO from here on out? Also I'm not sure about the dechlor situation. I use Seachem Prime but I'm not sure if chlorine is a factor moving forward.
When I switched to full RO water I remineralized it according to my target parameters and did frequent, small water changes to transition the tank over a few weeks. You DO NEED to remineralize your water. Pure RO water is too pure, and the cells in your plants and fish wonít have enough osmotic pressure to stop the pure water from flowing into them causing the cells to burst. (i.e., pure water is toxic). I looked up your Pro-Discus Mineral stuff that you have, but couldnít find the pH, KH and GH that it is targeting. Since you already have it, Iíd mix up a batch with your RO water, test the parameters, and decide if that seems suitable for the kinds of plants and fish you are keeping. Of course other things in the tank like aquasoil, wood, rocks etc. will also impact your water parameters so it might change a bit once in the tank. Most tropical fish and plants are really happy as long as the water is a bit soft (low KH) and neutral to slightly acidic. I wouldnít worry about pH too much, unless you have a pretty specific reason to be hitting a specific pH. Otherwise plants and fish are pretty hardy to pH changes and do well at a range of pHs, especially when water quality is good and clean. A slow transition to new water conditions through small water changes should be just fine.
Equilibrium is adding Ca, and Mg salts back into your tank (which combined is your GH reading). Ca, Mg and S are macronutrients for plants, so if your tank is heavily planted you probably want a fair bit of GH (6+ degrees). Equilibrium doesnít add KH so if going the Seachem route you will probably want to pick up their Alkaline buffer product too. Or you can use a system like @DaveKS
where he uses natural means to buffer his water. Waaaayyy better than adding chemicals, but takes a bit of art to it in addition to sound understanding of the science behind why you are adding these things.
You RO system should be removing chlorine from your water too. So no need to add a dechlorinator.
Bump: TDS is important to make sure that your RO unit is working. RO membranes usually have a target of 97-98% solute removal, so if you are starting with 320 TDS, RO water readings of 9 or less mean your unit is working nicely. Some shrimp keepers use TDS to check their water quality. Some use TDS when remineralizing their water with a shrimp specific salt solution to verify the correct dosage of demineralization salts. Otherwise TDS isnít very useful, because it doesnít tell you WHAT is dissolved in your water, only the total combined content of all inorganic and organic substances dissolved in molecular, ionized, or micro-granular suspended form.