Well I am a bit surprised as the white distilled vinegar seems to have done the job. I only took a before picture of the
grow rocks I put in the vinegar and added the pH down to, but that's basically what they looked like before the test with the vinegar by itself also. I think you can guess the before picture. The second one was with the vinegar alone, and the third one was with the vinegar and pH down. I did these tests with full strength white distilled vinegar, and both tests soaked for 48 to 55 hours.
I did rinse them at least 3 times before I set them aside to dry but there is still a strong noticeable smell of the vinegar. The next steep is to see If I can get all the vinegar out. I plan use bleach water to sanitize them, then rinse well and then soak with plain boiling water overnight a couple of times. That should do it I hope.
From my experience the vinegar has been able to clean even better than the Florakleen did. But the Florakleen is designed to be safe for the plants, you can flush the system with the plants in it with Florakleen, something I wouldn't do with vinegar. With regular use of Florakleen you can control the buildup of salts in any
growing medium as the plants are growing. A defendant plus, because these salts can keep the plants from uptaking the right balance of
nutrients. Although for a through cleaning between crops the vinegar could be useful, provided you can get all the vinegar residue out.
The next steep is to find out how much to dilute the vinegar. The distilled white vinegar is not real expensive, but it can be to use full strength when you need 4 or 5 gallons of it. Especially compared to the Florakleen at about $9 a quart, and they recommend mixing it at 1 to 2 teaspoons per gallon. Although I have been using about twice that for cleaning between crops, but not more than recommended when flushing the system while the plants are growing.
P.S. I will also do a test using just plain water and pH down to see if it's purely the pH that dissolves it, because there are many types of acids.