Continuous Water Change?
 

This post has two questions:

1. Does anyone currently do a continuous water change (water in & out) in their tanks? How big is the tank and how much per day/week do you do.

2. I recently read an article in FMAM that suggests doing only a 10% water change a week is not enough to stop the tank from reaching high levels of pollutants. So what is your opinion about how much water should be changed daily in a 46-bow tank that is heavily stocked (6 fish, 3 corals, 6 or 7 bivalves, lots of sponges and squirts, about 40 lbs. of LR). [If I take 50% of my tank volume and breakdown the math, I will end up changing 3.3 gallons per day or .14 gallon per hour. This number seems too small to have any affect on my tank.]

There are folks who have their Litermeter III's set up to constantly change water, some of them are pretty big tanks. A search for Litermeter III should turn up something.

I do this with my FW 120 and plan to do the same on my 54 SW.

The FW setup is very simple: litermeter I pumps water in from a brute 44 gallon, dual airline tubes siphon excess out to a drain. One end of the siphon airline tubes (full of water, not air) are held in the tank with a suction cup - they drape over into a 1/2" drain tube held in place with velcro. The height of the output side determines the water level. Water tension keeps the siphon lines full when the excess is drained out. 18 liters a day go in. A quick daily spot-check of the water level ensures the siphons are still working. If I lose siphon, it can run a couple days before overflowing (I think!)

I plan to use a Litermeter III for the SW. This, to me, seems to be a much more reilable way to do it. I would expect salt creep to be a real problem with a SW tank done the way I do the FW tank. With the LM III, you can dose kalk, iodine, whatever, as well with the top-off. Very nice.