Re: Increasing KH

 Stephen.Pushak at saudan_HAC.COM wrote:

>I think it is a good plan to check out potential substrate materials
>for calcium and magnesium carbonates PRIOR to setting up a tank and
>adding fish and plants. A silica or quartz sand/gravel should have
>little or no alkaline components.

 Thanks to Paul Krombholz I solved the problem. He suggested using
muriatic acid (hydrochloric acid) from the hardware store to pre-treat
the gravel. I found a 31.5% solution of muriatic acid for cleaning
masonry or for dropping the pH in pools. I tested 3 batches of gravel
from my 10 gallon tank (the one with a rising pH) and I found out that
the gravel contains quite a few "lime chips". This gravel passed the
vinegar test with a brio. I also tested 10 2 oz. samples of my new
gravel and I only found one "lime chip" that foamed. I will do some
more testing tomorrow and I will decide if to pre-treat it or not,
most likely I won't (the pro/contra arguments are another story).
-the vinegar test is totally unreliable if you are using table vinegar
-you might not experience a rise in KH unless you're injecting CO2.
I'm almost 100% sure that the tank water had 4dCH (like the tap water)
when I tested it the day I started injecting CO2 -I will keep a log
from now on<g>. Calcium carbonate combines with carbonic acid (H2O +
CO2) to produce calcium bicarbonate which increases KH. If I stop the
CO2 injection now I should get calcium deposits.
-commercially available muriatic acid is very suitable for testing the
substrate as long as you take all the safety measures. This acid is
very strong, I have a lot of experience in working with strong acids
so I knew what I was doing. If you use this acid,especially for
treating the gravel, PLEASE wear neoprene gloves, safety goggles 
(or sunglasses :-)) and do not inhale the fumes. Better do it outdoors.

Once again, sorry for quoting list#344.
 Didi Soichin
 didi at wwnet_com
 Westland, MI, USA