Such frequent pH adjustments just means the nutrient ratios are poorly chosen. I can go three weeks without adjusting the pH at all then, suddenly, *boom* it needs an every second daily adjustment (which if I'm lazy like at the moment, I am into since my last res change 10/25. That's when it's time to start over by mixing a new batch, for both of us...

All that vinegar you dumped in there is organic fermentaton sewer, basically bacterial poop. It is probably a nutrient formula to grow some microflora well, but not necessarily the good guys. So it's time for a res change IMO, since the system is overloaded with vinegar which depending on the type and degree of filtering can also contain a lot of other organic particles and macromolecules that seem not to be working in your favor.

If, after using an inorganic pH down you still have the problem, it is something else, but that is putting the cart before the horse. Maybe you'd have a bad initial nutrient mix specific for your set up, commercial or not, but more likely it would be an unintentional crash (deficient) diet with too small portions for the mass of vegetation your system supports.

A bottle of vinegar seems like a huge amount, but you didn't mention the system volumetric capacity. No matter. One step at a time and you'll get it under control without doing circles. Start the mix over, that's better than risking all the pH swings and whatever alien matter might be fermenting or getting eaten in the reservoir.

Oh, you did change it I see. Well, maybe it is just impregnated into the rock wool, roots and everywhere else and will take a few cycles to stabilize. That is not clear. Just one day later is common for the pH to creep back up a unit of pH as the system equilibrates all the buffering it has soaked up in many places, so watch it and see if it is a false alarm by the third day when it should have settled down. Or you simply have bigger plants that eat more and have them on a too weak solution.

This post was edited by PupillaCharites on Sat, Dec 7, 13 at 18:56

You didn't mention your water source. If it's tap or well, you could try buying filtered water or a filter and see if that makes a difference,