check valve on calcium dispenser

[upsetter]

Hey Roger, would it be ok to put a checkvalve right before the calcium/kalk dispenser to prevent any kalk backflow into my reservoir? Or would it put too much backpressure on the osmo pump? The checkvalve I have is airline tube size, so smaller diameter than the tubing that came with the Osmo set-up. Or I guess another question would be is there a checkvalve made for the Tunze size tubing. I've noticed kalk backflowing into my res-- I tend to put about 15 tsp into the dispenser at a time. Thanks as always!