Interesting! I found that my rez and tubes had a bit of a slimy feel to them and thought it might be some kind of fungal infiltration or bacteria, but I guess it's just the pH down. I recently asked for battery acid in Auto Zone and boy did I get an evil stare. So some have mentioned that using sulfuric acid could pose a potential health hazard from smoking or ingesting buds grown in water adjusted with H2SO4; I'm not sure why this would be the case? Does anyone have any good scientific evidence one way or the other?GH PH DOWN is made from phosphoric acid, which makes your reservoir pump and hoses slimy, especially during flowering. When the phosphoric acid hits the P saturated solution, a plume of phosphorus hits the water and the solution cant hold it all, some of it changes form to a solid and it becomes slime that sticks to everything it touches. I use sulfuric acid and I get no slime at all, all I have to do is rinse out my system once a week, almost no scrubbing at all.
You can get sulfuric acid at any auto parts store, just ask for battery acid. Cost is anywhere from $3.99 - $5.99 per liter, very cheap. You have to ask for it, they keep it behind the counter. Wear rubber gloves and goggles while handling it. For weaker strength, use 1/3 of a cup per gallon. For normal strength use about a half cup per gallon. Make sure you use RO water or distilled water. You dont want the chlorine from your tap water interacting with the sulfuric acid. A $3.99 container of battery acid will make about 8 or 10 gallons of PH Down.
My chemistry may be a bit rusty but I believe it would dissociate into a sulfate ion HSO4- and a hydronium ion H3O+. Hydronium ions are extremely reactive and will protonate most things they come into contact with. H+ ions are wht make solutions acidic, so a hydronium ion can easily release a proton into most solutions which will raise its acidity. This is basically the same mechanism of action as most acids. This leaves the HSO4- anion. Whether or not this would have any affect on health I don't know. The acid is being used in such minute quantities to adjust the pH of the water, and who knows whether it it is even being taken up by the plant's root system. I doubt that it would really have a deleterious affect on plants or human health at these levels, but I may be wrong. We need a real chemist to step in here. I could potentially see something like hydrochloric acid not being the greatest thing for your plants due to its dissociation into Chlorine anions (similar to bleach); chlorine is not the greatest for plants and roots.