I'm sorry dude, I just happened to read this last statement. When mixing up your nutrients you always have to put your most alkaline substances in first that means you start with your silica go next with your cal-mag work your way through your minerals and then finally your nitrogen goes in last.
So when I was concerned about buffers in your water your background water and you answered back with you using reverse osmosis, that should have been a real simple everything's okay just raise your nutrient level up. But now that I've gone back and read that you're putting in your Silicone last, that changes things.
Next time your home when you mix up a res the way you think it ought to be done, I'd go ahead and mix up some extra nutrients and keep them on the side. This may seem a little strange but if you have a weaker mix of nutrients and a stronger mix of nutrients and you're away in your wife checks things, and the pH of dropped again you can always add some of your stronger nutrients in mid-week. You don't have to wait for a full res change. Or if you need to use a week or mix you can do the same actually yes you can use water for a week or mix.