DIY RO questions

[Lucky Dog]

OK, so I just built my first RO system following the posts here. Thanks to all that put together information so that the rest of us can easily get started.

Anyway, now that my little unit is started, I seem to have more questions. LOL

I'm on my first pass through the RO, and my initial refracometer readings are starting at approx. 2 and the sap is coming out at 6 - 6.5.

Should I make multiple passes through the RO with the concentrate? Are there any negatives associated with multiple passes?

What affect does the output flow from the distillate and concentrate have on the operation of the RO?

The plan that I followed was the one that hodorskib outlined.

Thanks

[jmayerl]

It depends on the membrane and pump you have. Many cheaper membranes will begin to pass sugar as they go over 8%. Depending on the pump you have you may also not be able to get to a high enough pressure.

[Lucky Dog]

It depends on the membrane and pump you have. Many cheaper membranes will begin to pass sugar as they go over 8%. Depending on the pump you have you may also not be able to get to a high enough pressure.

Good information.
It looks like my pump is capable of about 100 psi, or maybe a little more.
As far as the quality of my membranes, I would assume they are on the low end of the quality scale. They are 100 gpd membranes that I got off Amazon.

As I play with this, it seems that if I slow the concentrate way down. to a fast drip, I can get 9% out of it. Does that make sense?

[hodorskib]

All of what you are describing makes sense. How many membranes do you have? and what pump are you using? Residential membranes can handle concentrates up to 8% after that the rate of process slows way down and they foul quickly.

[Lucky Dog]

I have the Aquatec 8800 pump and (4) 100 GPD membranes.

Would it make more sense to try to get to the high % in one slow pass, or run it through twice at a faster rate?

[blurr95]

I built the same setup this year. It is amazing seeing how much water it takes out.

Jason

[hodorskib]

Over the past several years I have found that the sweet spot (balance) between rate of process and concentrate level is 7-7.5% for my needs. You can get to higher level 9% but the rate of process goes way down. The difference between 7.5% and 9% is a difference of roughly 2 gallons of concentrate. At 7.5% it is 11.4 gallons for every gallon of syrup and at 9% it is 9.5 to a gallon. However, the amount the system can process per hour will go down dramatically at the higher level. Keep trying different concentrate levels until you find what works best for you and the amount of sap you collect.

[Lucky Dog]

Over the past several years I have found that the sweet spot (balance) between rate of process and concentrate level is 7-7.5% for my needs. You can get to higher level 9% but the rate of process goes way down. The difference between 7.5% and 9% is a difference of roughly 2 gallons of concentrate. At 7.5% it is 11.4 gallons for every gallon of syrup and at 9% it is 9.5 to a gallon. However, the amount the system can process per hour will go down dramatically at the higher level. Keep trying different concentrate levels until you find what works best for you and the amount of sap you collect.

I definitely noticed the rate change as the concentrate level went up.
Do you try to make 7.5% on one pass? or do you do multiple passes?

Thanks for all the great input and help!

[YBSean]

I definitely noticed the rate change as the concentrate level went up.
Do you try to make 7.5% on one pass? or do you do multiple passes?

Thanks for all the great input and help!


I have the same setup and run in recirc mode until sugar is over 4% in tank and at least 50% of H2O is removed. Then I run the concentrate into a separate tank and it measures 7+%. This is what I boil.


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[hodorskib]

I am running 6 150gpd membranes this year and I am able to do it in one pass. My sap has been very low this year averaging around 1.2% and it is still able to do it in a single pass.

[Lucky Dog]

With 6 150GPD membranes, do you need to scale up your pump capacities?

[hodorskib]

No, it is working just fine with the aquatech pump. I have been getting anywhere from 8-10 gph depending on how cold the sap is. The other day I collected with ice in the tanks so it was at 8 but prior it was holding around 10.