The pH value of the water in my 9L reservoir keeps rising. A few times per day i measure the pH (with the cheapest pH meter i could find), find it somewhere between 7 and 8 and put in a sip of natural vinegar (not distilled i think) to get it back between 5.7 or 6.5.
I’ve put nutrients in the water, there’s metal containers holding the pots, and i used little pieces of rope to conduct the water to the next plant. Could any of these be dissolving? Or is something else happining?
And more importantly: Is this bad, and if so, what do i do about it?