Originally Posted by
jberry
probably the temp change?
if your ph/ec meter doesnt adjust for temp. then i think that will give you different readings at different temps.
light, combined with nutrients and water may cause algae but if you arent getting algae then i dont THINK it would cause any changes in ph/ec.
also here is a chart that may help if you recycle your feed water:
Basic cheat sheet:
Ec goes up, PH goes down=plants require less nutes.
Ec goes down, PH goes up=Plants require more nutes
Ec stable, PH goes up=Equilibrium=Good thang.
the chart doesnt seem to apply in this situation but its good to have.