RO over the tank

[VTnewguy]

It really seems a big design feature on some of the hobby RO's is to have it mounted over the tank (horizontally vs vertical). I was wondering how many guys do that? Run the RO as a batch to the proper concentration then to the head tank? Run the first pass to the head tank with enough to get boiling then go back and fill a concentration tank first pass then a second pass? Just curious how some people RO without the specially built room.

[bowhunter]

I only have 130 taps or so but I'll give you my 2 cents worth. I run once through on my RO going from a little less than 2% sugar to 8-10% sugar in one pass. I don't store concentrate because it doesn't keep well unless refrigerated. I feed concentrate directly to the evaporator and use the ro to control the evaporator pan level. If you have a float to control the pan level, a small head tank will suffice. My ro is on a dolly so I take it into the garage attached to the house after I rinse at the end of the day to prevent freezing. I copied the dolly idea from Diesel Pro on this site.

[maple flats]

My RO is vertically oriented and is on wheels. I store it in a small heated room and roll it out to use it. I often run it thru once sending it to the head tank, usually about 2% up to 8%, then I recirculate from the head tank thru the RO again, but I start boiling at the same time. I have a site gauge on my 150 gal head tank, when the level gets down to about 25 gal I start sending new sap to the RO and run the pressure so I get slightly more concentrate than I'm removing in the evaporator. If the head tank gets over about 100 gal I switch back to recirculating from the head tank. Doing it this way my sugar levels range from about 8% up to 15% in the head tank, my average is about 11-12%. If my RO would do 14% in one pass, I'd do that and just run the RO to match the evaporator, I can't keep up with the boil if I try for anything over 8%, If I get a little low i the head tank, I turn the pressure back so I only get about 7%. At 7% my RO makes more concentrate than the evaporator boils away so the head tank fills more. That 15% I got was near the end of a boil when I had no more sap left so I just let the RO recirculate until it got down to just under my shut down mark on my site gauge, that is when I add the last wood. At that point I ran permeate to push the sweet from the membranes which brought it to just over the shut down mark.
To match my boil I need 1.3-1.4 gpm of concentrate (I get 80-85 GPH evaporation).

[VTnewguy]

Thanks Dave, I think we are going to have to figure it out as we go along. After looking at all the ro's at the open houses I really have taken a shine to a Memprotec 200h. I'll have to get another tank for it to rest on when we are running or build a insulated cabinet. (Which we will have to do anyhow)