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Re: nutrients



>++++++++++++++++++++++++++++++
>
>Paul says:
> 
>> O.K., I'll bite.  Why would a lower pH help with carbon uptake
>> when _not_ using Excel?
>
>Tom Says:
>
>No, lower pH by itself is not going to help (Not being a plant nutrient)
>unless it's due to addition of CO2 in a good range which is what I was
>suggesting ...
>

Aren't there other ways to lower the pH without adding CO2? For example,
peat in the filter or substrate. We know that peat will reduce reduce
hardness. Conceptually, it seems that this is due to the lowering of pH
thru the release of organic acids. Then, it seems that the lower pH shifts
the HCO3/CO2 equilibrium towards more CO2. [Please note that I am not a
chemist, so I await comments from Paul].
 I have a peat substrate tank that grew wonderful plants for over 5 years
without injecting CO2. I assumed this primarily was from HCO3 conversion,
in addition to supplemental CO2 from the slow decomposition of the OM.
Because I have soft water, I had to be careful to not let my KH get too
low.  When growth slowed after the first 5 years of relatively effortless
success, I added pressurized CO2 and everything has been fine since
(another 6 years).  Same substrate, albeit with less OM.

Neil
PS. I also did water changes and added traces, etc. :-)