maxxII- All of this is assuming I would hang the barrels, which I have only given thought to, not made a final decision. Like I said, my preference would be to set the barrels on a stand, just have to figure where to put them. As a side thought, "I was thinking they could be hung" and had called Atlas to see if the bows could support that much weight.
I could build stands that would let the top off barrels sit above the current barrels (up high enough to allow access to the bottom barrels).
I currently have nine barrels which get filled with RODI then aerate and buffer. Most of those barrels get mixed with salt but one stays fresh water only for topoffs. There is a pump that I move from barrel to barrel when I do water changes/top-offs on the vat or fill a tank. That pump can easily go to a 10' 6" head and then some (10' 6" being the top of the greenhouse). If hanging from the bows, I would build a wooden support platform for the barrels to sit on and hang the platform from the bows so the barrels could be removable for cleaning.
The kalk could be done a couple of ways;
1) have one of the current barrels on the ground dedicated to mixing/settling the kalk, then pump the clear limewater up to the barrel (whether it be hanging or on a stand)
2) continue with the current method of topoff and just add kalk to the freshwater barrel.
3) stand on a ladder to mix the kalk in the hanging barrels and let it settle there. The plumbing could be set up through a bulkhead so that the outflow comes from a few inches off of the bottom. (or stand on the vat to put the kalk in- I stand on it sometimes when I need to look down into a skimmer, and when I ran the airlines that are bubbling in the vat)
4) have a separate container (smaller-lower-easier to reach)) with the kalk and let the RODI drip from the barrel through that then to the tanks, but there are problems when trying to put too much kalk in too small of a container.
5) forget all of this and just manually dose the kalk. I'm sure I will have to do some this anyway if/when I get into some of the faster growing stonies or clams.
Remember too, kalk does not have to be mixed "saturated" so that it leaves allot of precipitate, less can be used so there is almost no precipitate. It can also be done in a slurry where a smaller amount is mixed and then just poured right in without letting it settle.
Currently on my private tank, I put 1/2 tsp kalk in an old milk jug and dump in 1 gallon of RODI then pour it into an old IV bag that hangs by the tank. (it is actually an old irrigation bag with 2,000 ml capacity) I use the roller clamp from IV tubing to regulate the drip rate. I don't let it settle and get nearly 0 precipitate in the bag. I used to get quite a bit of precipitate when I was using the RO water from the unit under the kitchen sink, but with RODI from the greenhouse, hardly any precipitate. I also have an unlit tank with Tubastraea and sponges that I just pour the other half of the gallon into.
Any drip system used that is exposed to the air is bound to build up some "crusties" due to the fact that there is carbon dioxide in our atmosphere. (combines with calcium to make calcium carbonate) This can usually be cleaned with a dilute acid such as vinegar or diluted muriatic acid.
Randy Holmes-Farley from the chemistry forum talks about his kalk dripper. It is a 44 gallon Rubbermaid can. He puts in the kalk, dumps water in from a five gallon bucket to mix the kalk, and then connects it to his topoff system. Says he only cleans the can about once a year or so.
melev- good idea. Kind of like the separate container idea I was talking about above.
casethekid- thanks for your kind words and encouragement.