I have obtained some supplies of high grade Potassium Hydroxide. I have been trailing it as a buffering agent in my systems and also to provide one of the three elements needed for AP systems that does not normally come in via the fish food. Just last week I found, using my "super dooper" digital pH meter that one little system (around 1200 ltrs in total) had drifted down to pH 5.43 I added 10g (one level tablespoon) of the flaked material. In just 3 hours the pH had come up to pH 6.52 A very powerful base indeed. I applied it in its flaked form by depositing it down the up stand coming from the fish tank, so that it would dissolve in there and be carried first to the sump and on to the grow beds that way it will be well mixed and diluted before getting back to the fish tank. The pH in that system is drifting down again and is now at pH 6.4 Potassium Hydroxide of this purity needs to be handled very carefully because it dissolves readily in water generating heat as it does so. Even small amounts of moisture on the hands will start the material dissolving imparting a very greasy feel to the hands. Burns would soon follow if left on the skin. Wash off immediately. We are looking for suitable packaging so we can pack it down to 500g lots I will post more info when we have sorted out post details and it is available.