Re: Water chemistry assistance

> Re: Water chemistry assistance
> --------------------------------------------------------------------
>    *  To: Aquatic-Plants at actwin_com
>    *  Subject: Re: Water chemistry assistance
>    *  From: George Booth <booth at hpmtlgb1_lvld.hp.com>
>    *  Date: Mon, 08 Jul 1996 09:16:17 -0600
>    *  In-Reply-To: Your message of "Thu, 04 Jul 1996 03:39:02 EDT."
>      <199607040739.DAA02513 at looney_actwin.com>
> --------------------------------------------------------------------
> From: John Lobingier <jlob at wpa_net>
> > I am adding 1/4 tsp of baking soda per day.  This is a 55 gallon tank.
> I use the rule of thumb that 1 tsp per 50 liters will increase the KH
> by 4 degrees.
> 1/4 tsp in a 55 gallon tank should increase your KH by about 1/4 to 1/3
> degree.  Keep in mind that both "1/4 tsp" and fractional dKH are hard
> to measure accurately.

Using baking soda, I now have increased my KH to 2dh.  It was at .5 to 
1dh.  My pH came up.  It was 6.0, but now it is at 6.4.

> > Here are my water values from 1 or 2 (?) weeks ago.

> > pH 6.0, KH .5 to 1dh, GH 7dh.
> > The results are after one day of adding baking soda in the amount of
> > 1/4 tsp:
> > pH 6.0, KH .5 to 1dh, GH .5 to 1dh.  I said GH .5 to 1dh.
> The lack of change in pH or KH is consistent with the very small
> amount of baking soda you added.  The change would be within the error
> margin for either measurement.
> > I retested all of the values because I was shocked to see the change
> > in GH.  Did the GH figure drop this far down because my plants are
> > extracting the need for CO2 ( carbon ) from my GH?  This is the
> > decalcification process or something like that in action?  The fish
> > are fine.
> No, GH measures mostly calcium and magnesium, not carbon compounds.
> It may be that plants are using the calcium and magnesium but the rate
> seems pretty high for that.  Are you adding anything to the water that
> would act as a chelator?  Peat in the filter?
No, I do not use peat in this tank.  I use no pH up or pH down chemicals. 
I do have two units ( bags ) of Dick Boyd's Chemi Pure in my Eheim 
canister filter.  This a combination of carbon and ion exchange resins.  
It is marketed for saltwater fish, discus, and African Cichlids.  It is 
suppose to keep the pH up.  It is not keeping the pH up.  I did not think 
plants used GH ( calcium and magnesium ).  I have two Onion plants.  Could 
they be the GH eating culprits?  These two Onion plants and my Java Fern 
are the only plants that are doing good. My other once healthy plants are 
going to the dogs.  I have a 5 year old sword plant that was beautiful and 
healthy and in the past it received only 40 watts of light.  It is now 
going bad.  My tank now has 120 watts of light provided by 1 Penn Plax 
Ultra Tri-Lux, 1 Coralife Trichromatic, and 1 Vitalite Power Twist.  My 
hygrophilia poly, and wisteria are also going bad.  The leaves are turning 
pale and brown.  I have always used Dupla laterite balls and Tetra plant 
tablets in the gravel around the sword plant.  I do not put laterite 
around the other plants.  I do put in some Aquarium Products liquid 
fertilizer N= 0.000%; P= 0.000%; K= 1.00%.  It also has chelated iron, 
manganese sulfate, and zinc sulfate. 

Thinking that my plant troubles were caused by a lack of CO2, I started 
the yeast/sugar method on the 4th of July.  I am getting one CO2 bubble 
from this per second.  I put the CO2 airline tubing into the intake of my 
Eheim canister filter.  The plants are giving off O2 bubbles.  The plants 
continued to decline so I moved all of the plants to another tank except 
for the sword plant.  I then made a 75% water change.  After this, the GH 
and KH readings did not change.  The GH remained at .5dh and the KH at 
2dh.  The pH is now at 6.2, down from 6.4.  Could the baking soda 
( sodium bicarbonate ) be throwing my test kits off?  

> Biogenic decalcification is the result of plants extracting carbon
> from the carbonates causing calcium to percipitate on aquarium
> surfaces.  This will actually raise the pH, even though it seems
> counterintuitive.

Then from what I have observed ( low pH/no dramatic rise in pH ) this is 
not happening in my tank. 
> > I have a 30 gallon plant ( if you can call it that ) :) tank with two sword
> > plants in it.  They are very healthy.  I have had them for years. I added
> > 1/4 tsp of baking soda to this 30 gallon tank yesterday and here are the
> > test results from today.
> > pH was 6.0, it is now at 6.6.  KH stayed the same .5 to 1dh.  GH stayed the
> > same 7dh.  The pH went up so shouldn't I see a change in the KH?
> Again, perhaps the results are confused due to measurement error.
> What kind of test kits do you have?  What is the resolution of the pH
> and KH test kits?  If the pH test kit has a resolution of 0.4 and the
> KH test kit has a resolution of 0.5, you have a wide range of possible
> values.
I use Tetra GH and KH test kits.  In my problem plant tank ( 55 gal. ) 
they now give me a GH reading of .5dh, and a KH reading of 2dh.  They used 
to give me a GH reading of 7dh and a KH of .5dh.  I also have an Aquarium 
Pharmaceuticals "general hardness" test kit.  It says I have no hardness 
at all.  I went out and bought a test kit by Wardley.  It like the 
Aquarium Pharmaceuticals test kit says I have no hardness.  

> > Baking soda ( sodium bicarbonate ) raises the KH only?
> Yes.
> > Is KH part of the GH?
> In generally accepted *hobbyist* terms, KH is the measure of HCO3- and
> CO3--; GH is the measure of Ca++ and Mg++.  KH and GH are totally
> separate.

> However, typical hobbyist test kits seem to measure total *alkalinity*
> or acid buffering and call the results "KH".  If carbonates are the
> only buffer in your water, i.e., the only contributor to alkalinity,
> this is OK.  If you have other buffers such as phosphates (from pH-UP
> or -DOWN or other additives), the "KH" measurement is up for grabs.
> Some test kits measure "total hardness" which is a combination of
> KH and GH.  This type of measurement is of little value to us.
> In general, I prefer the Tetra KH and GH test kits.  Our tap water is
> relatively low in alkalinity and the values we measure with these
> kits seem very "true".

Tetra KH and GH kits are the ones I use.  The water company report says 
our water has an alkalinity level of 10mg/l.    

> Just so I don't get flamed yet again by our chemistry professionals,
> "KH" and "degrees" are scientifically undesireable terms.  But since
> the test kit makers continue to use them, so will I.
> > Calcium carbonate will raise the GH, but not the KH?
> The calcium ions will raise GH and the carbonate ions will raise KH.
> George
Any ideas on all of this?  I am ready to scrap my 120 watts of light, and 
the CO2, and give my lonley sword plant its 40 watts of light back.  :)