Thanks Pat. I really appreciate your insight on this. I did initially have a problem with white stuff on the walls of my sump, but I seem to have corrected this issue by changing where I dose the Ca & Alk parts. Before, I was dosing Ca and Alk at the same place in my sump where the kalkwasser was entering (not dosing all at the same time, of course). After reading some other threads, I have now started dosing Alk directly into the tank (on right side), and Ca directly into the tank (on left side), and still have kalkwasser coming into the sump. Since changing to this, I still get some white stuff on the walls of my sump, but it doesn't build up nearly as fast as when I dosed all into the sump. But, maybe this is still an indication I am dosing too much? I also still clean my SEIO and RIO pumps about once a month, as the impeller in these seem to seize up from Ca buildup (I usually notice this when I turn off a pump & then it fails to come back on). However, I don't have this problem with my modded maxijet PHs. I had attributed this to the way the SEIO and RIO pumps are designed (ceramic shaft versus stainless steel), but maybe this is also something I should be concerned with?
I dose daily and test weekly. In my 45g tank (mainly softies) I am dosing 80mL of each part daily. In my 90g (mainly SPS) I am dosing 175mL of each part daily. My Alk tests between 8-9dKH in both tanks. My Ca has been slowly creeping upwards. I was targetting 420ppm, but last week when I tested it was 440ppm. My understanding from reading various posts, etc is that I should be focusing on the Alk to determine how much to dose, so that's what I've been doing. I've been dosing at these levels for about 2 months now. If it is too much, shouldn't I be seeing the Alk climbing too high? FWIW, my corals, fish, etc all seem to be thriving. SPS growth has been pretty darn good too.
Let me know what you think as I'm completely open to suggestions. I am willing to try dosing less, but I am under the assumption that I need to keep my primary focus on Alk level, which is how I got to the 80mL and 175mL numbers. According to the Reef Chemistry Calculator, 30mL would only raise Alk about 0.5dKH for 90g. From tracking my tanks, I'm pretty sure I am consuming more than that daily. Also, one small minor point, factoring in my sump and LR, using the volume calculator I calculated out my 90g tank to be 105g of water, and my 45g tank (sumpless) to be 37g of water. So my dosing numbers should probably be associated with those numbers rather than 90g&45g.
And yes, rainy month here in the Puget Sound area for sure!
rob
