Tank Overflow

[Amber Gold]

I'm looking for a new tank overflow setup that'll work better.

My existing setup is the sap/concentrate tank on the bottom and the permeate tank above. I need the permeate tank to be as full as possible because I need all the water rinse the RO with. At the permeate tank drain, I installed a tee with a vertical pipe going up to a couple inches below the top of the tank. This pipe has an elbow with a length of pipe down to an overflow tank set on the ground. The issue I've found is if the overflow pipe is left open, it'll drain the tank to the bottom of the elbow...lose say 50 gal of capacity. If I put a valve on the drain, I need to adjust the valve so it doesn't flow too fast or too slow...too slow and the perm. tank overflows back into sap tank. I also need a site gauge on the perm. tank so I can see how full it is...I just need to rig a float-pulley-weight setup to do this....not a big deal.

I was thinking of a normally closed valve connected to a float switch on the tank, but then it may not work say in the early season when boiling below freezing and the valve getting frozen closed.

So, what ideas do you have for an tank overflow that will keep the top tank full to the brim, and not something I need to monitor?

Thanks for the help.

[wiam]

Make a very small hole at th highest point in the overflow. This will keep it from syphoning.

[Russell Lampron]

What are you using for a Permeate tank? What I am doing this year is connect 2 275 gallon cage tanks together so that I can save all of my permeate. I plan to open the valves on both of the tanks so that they both fill at the same time. If I only have a small run to concentrate I can close the valve on the tank I am filling and only fill that one.

[Super Sapper]

Use a Tee instead of a 90 on top and leave the end pointing up open to avoid pulling a syphon. Drilling a hole a Wiam suggested will do this also but may leak depending on the rest of the piping.

[Amber Gold]

Sorry, tee not an elbow at the top with a short length of pipe to get it something higher than the tank.

Russ, I have a Lapierre 650 gal round bottom tank...4'x10'x33". I have a 550 gal poly tank the overflow pipe discharges into, so I can stock up on permeate if I want. I just need a better overflow system that keeps the Lapierre tank full to the top without me having to monitor it.

[wiam]

My main permeate tank has a bulkhead fitting as close to the top as I could get for an overflow to a lower tank. Amber can you show a picture? If it is how I think just lose the t and 90 and put an open topped pipe in he drain to the level you want.

[Amber Gold]

I'll try to get a pic this weekend. I thought about a bulkhead fitting, but then it'd mean drilling into a pretty stainless tank. Also the water would only fill as high as the bottom of the bulkhead fitting.