potassium silicate is basically what's in rhino and other silicate boosters.
how does it function with regard to buffering pH?
what about pot carb and pot hydrox? can you explain the mech for buffering? a link perhaps?
thanks
Potassium silicate will raise the PH, but not provide any buffers. It does provide some silica, which has shown to be beneficial. To make a strong buffer, you want to get some potassium bicarbonate, which you can get at any beer/wine making shop. You can also get it on ebay cheaply. This is what commercial hydroponic greenhouses use for PH buffering.
http://www.ebay.com/itm/Potassium-Bicarbonate-1-lb-/350574358104?pt=LH_DefaultDomain_0&hash=item519fdc2e58
To make a gallon of 13% potassium bicarbonate PH UP/Buffer mix 453 grams (1 lb) of potassium bicarbonate with one gallon of RO or distilled water. This will cost you about $7 and a gallon will last you a loooong time.
Potassium bicarbonate and potassium hydroxide are the main ingredients in PH up. They put a tiny amount of potassium bicarbonate in to say that it is buffered, but in such a small amount that it does not buffer for longer than a day or two. They do not make money if you do not keep consuming the product.
Potassium bicarbonate by itself is a fairly weak buffer. It must bind with calcium and magnesium to form strong, long lasting buffers in your solution. You want to add extra calcium and magnesium to your solution to assure that there is enough left for your plants to use after buffering. In short you must use a calcium/magnesium supplement with your calcium bicarbonate.
The combination of cal-mag and potassium bicarbonate will give you rock solid PH for a week or longer at a time. I strongly suspect that this is the "secret" to AN PH Perfect fertilizer. This would explain 'Big Mike's' rant against carbonate buffers, which are the industry standard. He does not want you to use them, because if you figure out how to do it yourself for a few cents a week, he cant charge you double for his "Ph Perfect" fertilizer line, thus he makes no money off you. He has Rolls Royce payments to keep up with, doncha know.
When using as a buffer, after setting the PPM of your solution to the desired level, add cal-mag at about 80 PPM for flowering, 20 - 40 ppm for vegetative. When everything is mixed, circulated and settled, add the 13% potassium bicarbonate solution in small amounts until you reach the desired PH. Calcium bicarbonate is a very strong base, thus a very small amount will go a long way. Err on the side of caution until you are know exactly how much you need to add. Keep track of how much you added for future reference.
I only adjust my PH once a week, on the day I change out my reservoir.
I can give a recipe for making the cal-mag supplement yourself if you want. It is very cheap to make, about $1 per gallon, but you have to order the chemicals online from crop king or jr peters.
You can order potassium bicarbonate already mixed with the magnesium sulfate (epsom salts) for stablizing PH from JR peters, but it will buffer longer and be a lot cheaper if you do it yourself.
Hope that helps.
My Opinion