yes, it works! i used it all the time before i got a few DWC buckets, then i went to PH DOWN and now i am having issues in my soil plants. but like Nova said, it does not stay long so its not good to use in Hydro, but soil it works fine.And the vinegar did the job without any adverse effects, spongey? Sounds like a goer! And as a bonus, you can get a 2L generic brand bottle here cheap as chips....