water is getting softer once it is in tank??

lousybreed

Aquaria Central Site Controller
Sep 7, 2004
664
0
0
Bay Area, CA
Ok my new 55 has been running for about 3 weeks and some strange things are showing up. My 55 doesnt have plants in it yet but it has 3.5" bottom of schultze aquatic soil (just like flourite) and i have a refugium where i have emergent plants growing (and growing fast i might add). I will be adding plants soon. Check this out:

here are my water parameters:
pH=7.0
NH3=0.0
NO2=0.0
NO3=0.0
dH=6.5 (kH=2, gH=4.5)

here is my question, how can my hardness be only 6.5 when out of the tap it is 9.5??????

type tap tank
kH 3 2 (hard to tell could be lower, more like 0.5-1.5)
gH 6.5 4.5
pH 7.5 7.0
can my plants in my refugium be ripping out the carbonates and minerals Ca and Mg and using them as nutrients??? Does clay substrate absorb these chemicals at first????? I mean could the carbonates and Ca and Mg's be adsorbing onto the clay soil??? would this explain the difference between tap and tank pH??? I areated the tap water to drive out the excess CO2 to get a true reading. what is going on????
 
AquariaCentral.com