To add to Ganja's post. Once you test your runoff PH and see that its at about 4-5, Then I would recommend flushing with reg. tap water(declorinated). You have to flush 2-3 times the container size to remove excess salts that build up. If your worried about drowning your baby's(and you should be), Then try my method: at the end of the flush pour some diluted H2O2 through and then take a water bottle which you drank about half of (you know the one, that half bottle of "stale" water sitting next to your bed on the table), Pour that through last. Its important that you drank from this container, The germs in your saliva will multiply in stagnant water, pouring it on after the H2O2 ensures that the extra O2 molecule will have some bacteria to react with and release the O2.
I started that method because I never heard the peroxide actually reacting to the soil.