Just thought I would add that just in the short time I have been using this (about a week) that the small amount of hair algae that I had is now dead or dying.  I think I read somewhere that the Kalk binds to phos and precipitates it out.  Can someone back me up on that one?

Fax

It will probably be between 3 and 4.  I'll give you a call.

How much water will it hold.  Will you be around today and can I stop by to see it.

Jody

I got it put together tonight and added the Kalk (pickling lime from Macey's for $.99/lb).  I put in 3 lbs so it should be good for awhile.  I added a total of 4 fans to increase evap.

View looking down from the top.  You can see the fence post used as a reservoir, on the top left is an emergency overflow to send float valve mishaps down the drain.  The red is a neat little contraption that makes an annoying sound when the water level gets too high (see float valve mishaps above), and the float valve from the RO is on the right.  Below the red you can see the exit for the Kalk solution to go down to the sump, just below that (not seen here) is a powerhead on a 2' piece of PVC on the end to stir the solution.  The powerhead will be on a timer to mix the solution about 3x/day.

Fax

If I put more kalk in the reservoir, will the pH go above 12.5?

No, that's max.

so if I put more kalk in it would just not dissolve until some fresh water was added.

Correct.

If your PH is stable @ 12-12.5, then you should have enough. It really is gonna depend on the amount of makeup water your tank will require. I use about 1-2 Tablespoons of alk per gallon in the reservoir being mixed. Test and tweak from there. I recharge with about 1/3cup lime as needed.

Jason