Home built RO pump question

[paulslund]

I am, like many, looking at a DIY RO system and I can't quite find the answer to my pump questions.

The "go-to" seems to be various models of procon pumps but when I search for their stats, they just seem to be a regular water diaphragm pump that have a capacity less than 1g/m and top out around 100psi. So why couldn't I use one of the lesser known brands like the attached? It pumps 1.6usg/m with a PSI rating of 130psi and is much cheaper..

Ignoring that a cheaper pump might breakdown sooner, what I'm really looking for is the answer to the following question: are the specs on this pump correct to push sap through 1 or 2 400GPD membranes? Is too much flow bad vs less flow (I know there is a minimum flow you need across your membranes) but I thought if the flow is higher than ideal it would just help keep the members from gumming up with sugar but might need to recirculate as my permeate / concentrate level might not be a 50/50 which is my goal..

Thanks to all for your help!
Paul.

https://www.amazon.ca/dp/B07BP7TDLJ/...v_ov_lig_dp_it

[DRoseum]

Were you looking at procon pumps or aquatec pumps? Many use aquatec 8852 for 1 or 2 of the 400 gpd membranes. I did this for a few years.. However a better option is the Coronwater TYP-8900 pump. Much higher flow rates at higher pressures. Can actually go up to 5 of the 400 gpd membranes in series with that pump. I have built 2 units like that - use both in parallel for big runs or one at a time on slower days. Both aquatec and coronwater are diaphragm pumps and can self prime and run dry. Good for smaller operations. Much like what the RO bucket uses in its RB5 - rB25 models.

The one you linked to would not work. The flowrate is probably open flow at 0 pressure. There is a reason its so cheap.

Procon pumps are rotary vane pumps.

[paulslund]

Were you looking at procon pumps or aquatec pumps? Many use aquatec 8852 for 1 or 2 of the 400 gpd membranes. I did this for a few years.. However a better option is the Coronwater TYP-8900 pump. Much higher flow rates at higher pressures. Can actually go up to 5 of the 400 gpd membranes in series with that pump. I have built 2 units like that - use both in parallel for big runs or one at a time on slower days. Both aquatec and coronwater are diaphragm pumps and can self prime and run dry. Good for smaller operations. Much like what the RO bucket uses in its RB5 - rB25 models.

The one you linked to would not work. The flowrate is probably open flow at 0 pressure. There is a reason its so cheap.

Procon pumps are rotary vane pumps.

Ah.. (sorry.. I meant the aquatec) I was forgetting the flow under pressure would be different than the stated flow rate.. unfortunately can't find that info on that pump, so I'm guessing there is a reason for that.

I found another pump that indicated "working pressure 100 psi" and "working flow 10gph".. I'm guess that means the flow is still 10pgh at 100psi? If so then I guess those are the markings I'm looking for on a pump. The 8852 has a stated flow rate of 41GPH at 80PSI (i..e. 2.6L/m).. are those the kind of flow rates I need to run this set up properly?

Is there a metric to follow regarding pump working pressure flow rate to membrane size? 400gpd is 16gph (understandably at 70 Degrees and probably at 60psi) and the aquatec working pressure (at 80psi) is about 2.5 times that rate.. although when combined with 35-40 degree sap (slower gpd) it could be 3-5 times higher? Just trying to understand what the ideal ratios are..

I'm debating if I build with a 400gpd membrane to get through my 55gal barrel in a few hours, or something slower that I just run overnight to be ready in the morning..

Thanks a lot!

[maple flats]

I guess my only input will be, if you do get the pump you linked to, get a couple of spare diaphragms and if they are not available, don't get the pump!
Not for an RO, but rather for my water flow, I use a 120V 3.2 gpm diaphragm pump. In the 6 years I've been using it, I've had to change a diaphragm 2x. It's a 5-10 minute job, but if a diaphragm fails the pump is useless. I now keep 2 spare diaphragms on hand, I was just keeping 1, but when I needed it, I turned around to order another but it was temporarily back ordered. I then ordered a spare pump the same as I had and I increased my diaphragm order to 2. The new pump arrived (in 2 days) several days before the 2 diaphragms did. Fortunately I didn't need one before I was in possession of the new pump.
Those little pumps might go years on one diaphragm, but then you could need to swap diaphragms 2x in rapid succession. Keeping ice from passing thru is a major cause, but other things can cause it too.
This being said I generally keep at least 1 spare of most equipment, it's just my M.O., When I was still actively tapping, collecting and making syrup, I always had spare parts for most if not all equipment. I kept a spare feed pump for the RO, 2 spare membranes (it had 2 in use), 4-6 spare cordless drills for tapping (you never know when someone will offer to help, a minimum of 2 batteries for each drill, spare drill bits (real tapping bits), spare IBC totes when I was hauling 3 on my 16' gooseneck trailer, 3 or 4 syrup hydrometers, 3 sap hydrometers, and so on. I even kept a box of spare caps for the IBC totes, for when one got lost. I even had 3 sap pumps for filling my IBC totes from my sap tanks, 2@1.5" and 1@1" just in case.
This may sound extreme, but if you are serious about making syrup it's a good policy to follow.

[Swingpure]

I guess my only input will be, if you do get the pump you linked to, get a couple of spare diaphragms and if they are not available, don't get the pump!
Not for an RO, but rather for my water flow, I use a 120V 3.2 gpm diaphragm pump. In the 6 years I've been using it, I've had to change a diaphragm 2x. It's a 5-10 minute job, but if a diaphragm fails the pump is useless. I now keep 2 spare diaphragms on hand, I was just keeping 1, but when I needed it, I turned around to order another but it was temporarily back ordered. I then ordered a spare pump the same as I had and I increased my diaphragm order to 2. The new pump arrived (in 2 days) several days before the 2 diaphragms did. Fortunately I didn't need one before I was in possession of the new pump.
Those little pumps might go years on one diaphragm, but then you could need to swap diaphragms 2x in rapid succession. Keeping ice from passing thru is a major cause, but other things can cause it too.
This being said I generally keep at least 1 spare of most equipment, it's just my M.O., When I was still actively tapping, collecting and making syrup, I always had spare parts for most if not all equipment. I kept a spare feed pump for the RO, 2 spare membranes (it had 2 in use), 4-6 spare cordless drills for tapping (you never know when someone will offer to help, a minimum of 2 batteries for each drill, spare drill bits (real tapping bits), spare IBC totes when I was hauling 3 on my 16' gooseneck trailer, 3 or 4 syrup hydrometers, 3 sap hydrometers, and so on. I even kept a box of spare caps for the IBC totes, for when one got lost. I even had 3 sap pumps for filling my IBC totes from my sap tanks, 2@1.5" and 1@1" just in case.
This may sound extreme, but if you are serious about making syrup it's a good policy to follow.

Good post. I was waffling on getting a second transfer pump, because I will rely on it so much, and now for sure I will. I will also look into getting more diaphragms for my RO pump and will get a second real tapping bit. Thanks.

[DrTimPerkins]

This may sound extreme, but if you are serious about making syrup it's a good policy to follow.

As Dave says, it's good policy to follow. The sugaring season is very short, and tends to be about 2-4 great runs (30-50% of the crop), 5-10 moderate runs (30-50% of crop), and 5-10 so-so runs (5-20% of a crop). Doesn't hurt much to miss the small runs, but you miss just one or a good share of one of those great runs and you can lose 10% or more of your total crop. Most larger producers are ready to fix things quickly at those times and have spares for anything they can and have backup plans (more storage) for things they can't fix right off. It can REALLY hurt the bottom line when something happens that you can't fix immediately. For smaller producers....maybe not as critical to the bottom line, but still painful.

[paulslund]

Were you looking at procon pumps or aquatec pumps? Many use aquatec 8852 for 1 or 2 of the 400 gpd membranes. I did this for a few years.. However a better option is the Coronwater TYP-8900 pump. Much higher flow rates at higher pressures. Can actually go up to 5 of the 400 gpd membranes in series with that pump. I have built 2 units like that - use both in parallel for big runs or one at a time on slower days. Both aquatec and coronwater are diaphragm pumps and can self prime and run dry. Good for smaller operations. Much like what the RO bucket uses in its RB5 - rB25 models.

The one you linked to would not work. The flowrate is probably open flow at 0 pressure. There is a reason its so cheap.

Procon pumps are rotary vane pumps.

So I've researched more pumps trying to get the flow rate at high pressure, but the cheap ones don't seem to provide that info, so I think you are correct that they won't work for this application.

I am still confused about flow across the membrane. I found your Youtube video explaining the basics (great videos on your channel btw.. thank you!) were you discuss recovery rate should be a goal of 20% to keep the membrane clean. However in your other video where you demonstrate the single membrane RO (the one from 2019) you clamp down the pressure to obtain a 1:1 ratio of permeate/concentrate. Does that equate to a 50% recovery rate for the one membrane?

Or did I misunderstand the whole concept?

I can't seem to find the Coronwater 8900 in Canada..only the 4000, which seems to have 1/2 the flow of the 8900 (i.e. 2.5lpm @80psi vs 5lpm)...I did find the specs on the aquatec 8852 which is 1.4lpm @ 80psi, so the coronwater 4000 seems to be the better pump for almost the same price (although I think I can get the 8900 via aliexpress..just have never used that site before).

Thanks!

[DRoseum]

Thank you. Yes you are correct in your understanding. It works at 50/50, just more membrane fouling which can reduce effectiveness/life of membrane over time.

Aliexpress is legit. I've bought thru there a few times.

[Swingpure]

Dan is this the pump?

https://www.aliexpress.com/item/1005...d=TlS4rCQZrXF7

https://share.icloud.com/photos/0e0w...pDmv3o4ZMo0n8w

[DRoseum]

Yep that's it.