Kalkwasser Auto-Topoff Doser

 

My kalkwasser / auto-topoff system consists of a SpectraPure 80 GPD RO/DI system that produces 18 MOhm laboratory grade water that is hooked to the cold water line of my muck sink faucet. The SpectraPure unit also contains a flush-valve which allows the user to flush the RO membrane after making topoff / waterchange water and it also has a purity monitor which allows the user to test their water to ensure that the water is pure. The SpectraPure unit is plumbed into an 18 gallon Sterlite storage tub fitted with a 1" bulkhead at the bottom of the tub where the water exits the container. The bulkhead is fitted with two ballvalves and a threaded nipple off the side. The two ballvalves allow the user to control the flow of the water. The user can either shut off the flow right from the Sterlite tub or the user can use the second ballvalve to draw off a certain amount of water without detaching it from the dosing pump. Mrs. Wages pickling lime (purchased for $1.69/lb at the local supermarket) is added to the Sterlite tub at a concentration of 2 tsp / gallon. I also add about 200 mL of white distilled vinegar to my kalkwasser solution (which is roughtly 3 mL / L kalkwasser). The addition of the vinegar yields a slight increase in the calcium concentration of the solution as well as it increases the alkalinity of my tank by providing an additional organic carbon source for bacteria to oxidize. The oxidation of the vinegar via bacterial action in the tank after it's been dripped yields increased alkalinity. Craig Bingman has written extensively about calcification on the Aquarium Frontiers online magazine. I suggest you head over to Kevin Done's Aquarium Frontiers Index and checkout the Biochemistry of Aquaria link where Dr. Bingman discusses the use of vinegar in kalkwasser for added alkalinity. The entire mixture is mixed for 15 minutes one time per day using a RIO 800 powerhead submerged in the tub about 8 hours prior to dosing using a dosing pump. A large piece of styrofoam is floated on the surface of the kalkwasser mixture to minimize the amount of contact that the surface of the kalkwasser has with the atmosphere thereby minimizing the contact with atmospheric carbon dioxide. The feed line is then plumbed into the dosing pump using 1/2" flexible tubing.

The dosing pump is a Pulsafeeder Series A Plus electronic chemical metering diaphram pump that I purchased off of E-Bay for less than $100 US (including shipping). Pulsafeeder is the manufacturer of the Reef-Filler diaphram dosing pump sold on Champion Lighting's website and other aquarium websites across the web. This particular pump is a 12 gallon-per-day chemical dosing pump that is variable from 0.12 GPD to 12 GPD by means of varying the stroke length and stroke rate of the diaphram. The input and output from the diaphram is mounted vertically to allow the pump to pump fluid vertically. Originally I had it mounted horizontally and I couldn't get it to pump more than 5 vertical feet and then I realized "DUH!" the check valve can't seat properly in a horizontal position so I switched it back around and VIOLA! it worked. I have it set on a timer so that it doses kalkwasser into my tank from 1 AM to 1 PM during the "lights off" cycle of my tank lighting. Setting the pump on a timer also allows the user to control the total GPD to a much smaller volume than what is possible if the dosing pump were allowed to have power 24 / 7. Currently, the dosing pump is set at 20% stroke rate and 50% stroke length and this yields approximately 1 gallon of kalkwasser topoff water in a 12 hour period.

On the output side of the pump I had to fabricate a custom reducer so that I could fit a 1/2" vinyl tube into a 1/4" aquarium airline. The reason I used a 90 degree elbow was because I could not find a threaded straight piece of PVC in my local (S)Lowes. So far it's working very nicely and is easily withstanding the approximate 6.5 psi being put on the fixture.

The 1/4" aquarium airline then ran up the wall and across the basement rafters and then thru the ceiling into the first story room where my 40 gallon reef tank is located. The airline then travels up to the top of the tank where the kalkwasser is dosed nightly. I don't currently have a sump so it's dripped directly into the tank in a high water flow area.

This system is working out very well for me and overall I am very happy with it. Here's a left view and a right view of the kalkwasser system. I would guestimate that I spent no more than $130 on the system. Future plans are to plumb in a float switch to start/stop the RO/DI unit so that I don't have to remember to make water every 2 weeks. I would also like to possibly plumb in a float switch in my tank so that the dosing pump would automatically turn off if for some reason the evaporation rate in my tank changed.

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