el barto haha just an idea i meant dilute the acid alot with water.
i wouldnt use viniger. unlesse it's hydro. its about the same to flush two weeks ya your right .
I also used vinegar as a ph down for a while but couldn't keep my soil from going alkaline...around 8.0. I have looked into this and found out that vinegar is readily soluble in water and will adjust the ph just fine, but when added to a soil medium is not strong enough to keep the soil acidic. I don't know exaclty what the chemistry is beind it, but the soil is able to buffer the vinegar or the vinegar drains from the soil too readily; after less than a day the ph of the soil will go up to a point close to the tap waters original ph before adding vinegar.
I believe a stronger acid that doesn't buffer as readily is needed to keep the soil ph values in check. If you don't want to buy the hydro store pH Down muriatic acid (used in pools and can be bought at a local hardware store) can be used. That stuff is pretty nasty in terms of exposure rand handling risks and only small volumes would be needed so be really careful and keep your safety in mind vs. your wallet. Another solution and one that should be used for instant soil pH change is aluminum sulfate or iron sulfate (available at most nurseries) These are acids that you add into the soil that will instantly change the pH and will help buffer the soil for some length of time (up to a year or so). Be carefull with the application as the roots can be badly damaged by over application or non thorough mixing. I don't know for sure, but I believe once the soild has been loaded with the propper amount of aluminum or iron sulfate, that it is much easier to keep the pH from shifting up if you use an alkaline tap water.