Calcium lactate Calcium lactate provides a nice simple soluble rich source of calcium for addition to drinking water. It is useful when known problems exist such as with species which have a particular problem. We recommend NUTROBAL or ARKVITS as a routine vitamin to provide the vitamin D3 needed to make the calcium available. ZOLCAL-D provides a source of calcium and D3 together where dosing is needed or where supplementation is always via the water. In this case alternate ZOLCAL-D with BSP drops.