Calcium builup in pumps and equipment
 

I just finished clearing my OM 4 way of heavy calcium deposits. I also routinely need to clean my pumps to keep them working properly. I'm just wondering what is a normal time frame for these deposits to form to the point of requiring removal. I'm finding 6-8 months is about when I need to do so to avoid problems. Much longer than that and I start to experience problems, ie: pumps not restarting, noisy operation, poor performance. Does this seem normal or do I have some other issue at hand. I try to maintain my CA level at around 400, and my alk is usually around 9 dkh. I'm using both a kalk reactor and a CA reactor.

My FOWLR tank which has no CA added other than by water changes does not experience much noticeable buildup despite having similar levels.

The trick to calcium deposits is Magnesium. If you maintain your Magnesium level around 1350 or so, you'll have a lot less calcium precipitate out of your water.

6 to 8 months seems to be about my schedule as well.

My mg level is at about 1200, a bit low but not drastic. I figure the buildup is most likely just due to the ca suplimentation regime, but wanted to be sure its not unusual.

I feel that your estimates are about right, so you have nothing to be concerned about. I also agree with keeping your mag levels about 1300.
But the trick to long , quite pump life is to do regular maintance , I service all my pumps every 3 to 4 months