Originally Posted by mrg02d
...I hate to go plunk down $35.00 on a test, but I guess its worth knowing rather than wondering, huh?...
If you're going to have a reef tank, $35 is a plop in the bucket. Keeping corals and NOT knowing your calcium/alkalinity levels could end up costing you big time $$ if the corals die.
If you're using Instant Ocean, your calcium is going to come in around 360ppm or so. So if you want to shoot for 420, you're going to have to - at a minimum - get your calcium up in your tank/PWC
water to start with using a calcium additive. That is a given. Other folks that use higher Ca
salts (like Oceanic) don't have that issue. Not saying you should change salts... just pointing out one of the numerous reasons some folks might not need as much calcium supplementation as others.