Hobby RO Pump Suggestion

[DRoseum]

Hey Dan,
My apologies for always ‘piggybacking’ on others questions to ask another question BUT it is somewhat related. In regards to the Coronwater TYP-8900K pump, can 600 gpd RO membranes be effectively employed with this pump? I saw your 2023 build incorporated five 500 gpd RO membranes in series - have you attempted anything with 600 gpd day membranes with that pump?

Yes I am using a 600 gpd membrane in each of my units with 5 membranes in series. 600, then 4 x 500. Works great.

[DRoseum]

Glad the videos help and you like the cooler setup.

10 amps may be enough but I'd prefer to have headroom well above peak load. Typically you don't want to exceed 80% of rating.

Also, careful heating your sap. Not only does increasing the temp promote more bacteria growth (below 180F) it also runs the risk of heating about the temp limits of membranes.

As for the peroxide, I wouldn't leave it in the system that long. I'd probably rinse with permeate soon after. The oxygen released by peroxide can be pretty damaging to all kinds of materials like plastics and rubbers. Short term exposure is probably fine, but would recommend it for long term. I use food grade peroxide (diluted to 3%) to clean my tubing. One year I left it in and it made many of the fittings incredibly brittle. Now I pull it dry after cleaning with my vacuum pump and don't have any issues.

If you flush the system immediately after use liberally with permeate and let it run until it pushes air out, I think you will be fine without a wash in between uses. Also, depends on temp of where it's stored. Mine stays between 34 and 38 F so it won't freeze and it's not warm enough to breed bacteria when not in use.

I don't do a soap wash every day and typically only do one per season (if it's been really warm) and at the end of the season. Pushing tons of permeate through after each use works fine. I just did a video on membrane storage this past year amd you can see how clean my membranes look in that for reference.

[BartzFarm]

Also, careful heating your sap. Not only does increasing the temp promote more bacteria growth (below 180F) it also runs the risk of heating about the temp limits of membranes.

I hadn't thought of that one. Makes sense though. I purchased the membranes you promote and they said "Recommend work pressure is 100 psi when using this product in a Maple Syrup reverse osmosis system. And we suggest heating and maintaining the raw sap at 104°F(40°C) to prevent clog on the membrane while keeping it under 113°F(45°C) to avoid damage to the membrane due to over-high temperature." I kept it around 90 degrees.

I use a 35% concentrate of peroxide diluted to 1.2% as recommend by the Membrane Solutions "Hydrogen peroxide solution, such as diluting 17 oz (0.5L), 30% H2O2 with 3.17 gal (12L) of deionized water, and then cleaning the membrane surface, is particularly effective for organic pollution."

I just got done rinsing the peroxide out. I ran it dry then replaced the sediment filter and flushed with permeate for about 30 min then ran it dry again. We got a cold spell and the sap stopped running but next weekend looks promising. Hope it's good to leave it that way till then. I keep it in my 60 degree basement. I may run permeate through it again before the weekend. Or try that carbon filter flush again. Great idea, by the way.

I think I'm starting to get the whole cleaning and maintaining process now. Thank you so much! Oh, and I already bought some Sodium Metabisulfite and starting building my PVC pipes... Genius!... Super Genius!

I got to be honest with you though, I'm still try to wrap my head around recovery rate but haven't given up yet.

[fireant911]

... I got to be honest with you though, I'm still try to wrap my head around recovery rate but haven't given up yet.

DRoseum,
I, too, am very confused about the recovery rate. This subject comes up frequently and the last time it appeared I started looking up the topic of recovery rate and went down a few rabbit holes... and unfortunately, I am still not understanding this. In reviewing your diagram, the recovery rate that applies to your last membrane makes sense; however, some of the literature that I came across gives VASTLY different calculations for the recovery rate. For example, take a look at the diagram located here: https://www.snowate.com/knowledge-ca...-analysis.html. According to this reference, the recovery rate for a single RO with a 15% recovery would be 15% (no surprise there!). Adding a second RO membrane in series would now have a recovery rate of 27.75%. The addition of a third RO membrane in series yields a recovery rate of 38.59%. A fourth membrane increases the recovery rate to 47.5%. With five membranes in series the recovery is shown as 55.63%. The math behind this is straightforward YET I know that this recovery rate does not bode well with what the RO manufacturers recommend. Is my confusion stemming from the fact that we are interested in keeping the stuff that is normally discharged in conventional RO systems? Could the 55.63% in a five RO in series represent that 55.63% of the solution is permeate while the remaining 44.37% would, in theory be concentrate? Am I confusing the 'system' recovery rate (i.e., when considering ALL the RO's plumbed in series) instead of looking at each individual recovery rate associated with each RO membrane? What am I misunderstanding here?

[DRoseum]

No problem at all guys - just glad to help out.

As for the pump, yes, I bought on aliexpress and bought the 24 vdc transformer on Amazon.

Aliexpress is very legit. Yes shipping is high, but the overall price is low compared to even less powerful pumps.

[ADK_XJ]

No problem at all guys - just glad to help out.

As for the pump, yes, I bought on aliexpress and bought the 24 vdc transformer on Amazon.

Aliexpress is very legit. Yes shipping is high, but the overall price is low compared to even less powerful pumps.

Good to know, thank you - any thoughts about doubling up two of those pumps in series to drive a 4x40? Would a 4x20 be more realistic?

[DRoseum]

Are you adjusting the needle valve on your concentrate line to increase pressure?

Some basic things to check that I've seen before
(1) pre filter housing installed in correct flow direction
(2) are all your membrane housing ports correct? Make sure you aren't mixing up which one is permeate amd which one is concentrate.
(3) are you processing sap? Water won't get up to 100 psi

I used 3/8 in my 5 x 500 builds without any problem.

[sweet acer]

Thank you Dave. My 81 year old brain must have been foggy as I now remember the water issue. Checked everthing else and was built correctly. We have had subfreezing weather for at least 10 days so will have to wait a few more days to test it on sap.
Thanks again.

[sweet acer]

I just built a 5x400 RO with a new 8900k pump but can only about 30 psi. I adjusted the pressure screw in untill it got extreemly loud but was only able to get 80 psi. The only difference between this build and my previous 3x400 is the size of the hose. i used 3/8 hose for the 5x400. Any suggestions?