I read some where that using baking soda your pH Max's out around 7.6
Your tank specs are similar to mine (New Zealand). I use excell and ferts in
a AR850 tank Its alot tidier than my old system of bottles and diffuses
etc.
Mike





"blank" wrote in message
...
My tank is 75gal low light, medium stocked community freshwater with at
least 1/3 plant cover, no CO2. For the past couple of weeks I've been
adding Flourish, Trace and Nitrogen at the recommended rates, and do a 50%
water change weekly. The plants have improved in colour and growth very
noticeably.

Tank water: pH 7.8, GH 6, KH 5, Nitrate 5, Phosphate 0.75 (Tap water is
8.4, 3, 3, 0.25)

I've finally begun to try to raise the KH in an attempt at increasing the
CO2 level, so added 3 tsp baking soda, which produced little change, then
added the recommended additonal 3 tsp today, which brought the KH up to 8
and didn't affect the pH. So far so good.

Looking at the standard CO2/KH/pH table, it seems I need to increase the
KH
to about 20 to even get close to the optimal CO2 level. Which means I'm
going to be adding a lot of baking soda each week. My plan is to add 6
tsp
daily, monitor KH & pH, until I get up toward a KH of 20, and then, once I
know how much to add, add the appropriate amount with my weekly water
change
in order to maintain the high KH. Does this sound like the right
approach,
or am I about to create another disaster?