Question about RO water

Distilled, deionized, and reverse osmosis (RO) water can all be neutral, but their pH levels depend on how they interact with the environment. Distilled is the only one of 3 that meets the "definition" of neutral, sitting at perfect 7 everytime at room temperature. Reverse osmosis (RO) water is slightly acidic, with a pH of around 6–6.5. This is because RO systems remove minerals like calcium and magnesium that help maintain a neutral pH. However, some RO systems can add minerals back in to raise the pH. RO water can be 6.5 to 7.5. Ro water will never be truly neutral unless mediated by hand. So should be ok so long as your ph metre is calibrated well. Deionized water uses ion exchange resin to remove a large number of anions and cations in the water, but it cannot remove all ions. Distilled water is condensed when steam encounters cold, so it basically contains no ions (except hydrogen ions and hydroxyl ions). Reason your metre cannot read anything in pure 7 water is there is nothing in it that can pass electrical current. Electricity cannot pass through distilled water because there is nothing In it to do so. Even a tiny amount of minerals will give it a electrical conductivity. Which in turn make it readable so long as you have it calibrated correctly and is in good condition.

Yes you can, i am using RO water my self! I would recommend measure one and documenting the value's so yu never have to repeat this step again. What ph pen are you using? (stay away from the cheap shit) I havent had any issues im using Apera pc60

to add onto number answer, RO water or distilled are aggressive AF and try and dissolve things into them for a equilibrium effect. RO water needs to come in plastic pipes as its so clean it will start to strip the metal pipes and break them in no time. PH your solution at the end after everything else has been added in. Don't let any probes sit in pure RO water your just going to damage them.

RO will be 7 by definition. If it has trouble picking up a reading it is because the H+ activity is beyond resolution. No, it will not fuck up the meter, it'll just read inconsistently at worst. pH is a ratio of hydronium to hydroxide. If levels are super low you might get a 10:1 one second and a different ration the next because the normal fluctuation is a greater proportion of the total, but if you took enough measurments it'd still average out to 7 pH. If there are very limited or no proton donators/acceptors (acids/bases, respectively) in solution then there is a neutral pH by definition, or 7.