Arnim wrote:
Now the real question: Am I doing my usual over-obsessing and worrying
about something that is probably fine?
Yes!
Okay, finally the water question. I was at first mixing my tap water with
RO water 50/50 to get my KH and pH down so I wasn't having to inject so much
CO2 to drive the pH from the usual high tap level of 8.2-8.4 down to 7 in
order to get enough CO2 dissolved in the water.
You express a common misperception here. No matter what your starting pH, a
given amount of CO2 will drive it down the same amount. There is not need to
"drive the pH from the usual high...in order to get enough CO2 dissolved in the
water."
The best reference for CO2 issues is he
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
This all seemed fine until
Carl at the LFS convinced me I should be using straight RO water
reconstituted with RO Right.
Things are getting worse, at least for your pocketbook. There is absolutely no
justification for using RO water for aquatic plants. This is a myth that seems
particularly prevalent at LFS, even good ones. Having said that, my planted tank
is pure RO reconstituted with RO Right, but I do that for the sof****er fish
(apistos) which I breed in that tank.
What is your goal? A healthy planted tank? Then measure your KH, and set your
spiffy pH controller to give you 20-25ppm CO2. At your KH of 6, that means 6.8
or 6.9. Now you're done, sit back and enjoy the tank.
So what is my GH? Do I really need a TDS or conductivity meter? I also
read in the archived newsgroups that although very low TDS most certainly
indicates soft water, high TDS does not necessarily mean high GH (meaning I
could be measuring other non-GH type solids, sodium?). Does that mean a
conductivity meter is better. Would one of those $50 jobbies be okay from
DFS?
You not need a TDS meter. Measure the GH out of the tap. If you dilute it 50%
with pure RO, GH will go down by 50%. With your hard water, you undoubtedly have
plenty of calcium and magnesium for your plants, which is the only reason to
think about GH at all.