Ryan, I made one with a coke bottle, airline tubing and a finger controled roller type "thingy" I bought off ebay. I drilled a hole in the lid to the coke bottle and siliconed a piece of airline tubing in it. I made a small hole in the bottom of the coke bottle. I threaded the other end of the airline tubing through the roller contraption. I mixed my prebaked baking soda with water, according to reef chemistry calculator and dripped it slowly into my sump. Being a nurse and an old one at that, we used gravity drip IVs in the old days and we used this thumb control mechanism on all ivs. Just remember there are 15 drops in 1cc (ml) using this mechanism. You will be able to regulate your drip rate into your tank using the above calculation. I made a hanger on the top of my coke bottle so I can suspend the bottle over my sump and let gravity and the controller take care of the rest of it. I will see if I have some pics of this set up I can send to you, as I know this is very confusing.