Two 150gpd ro membranes

[jason.kennedy.98478]

Because I have well over 1000gallos of fish tanks edit: sorry closer to 800

In that case check out iSpring, the make a 500 gpd 5 stage unit with a booster pump for 550 to 600 depending on where you get it, great deal

 

[Buckeye Hydro Verified Sponsor]

Hi Guys - at 300 gpd permeate and a 4:1 ratio your feedwater would be at 1500 gpd, or 1.04 gpm. Realize that 10" x 2.5" carbon blocks have a max flow of 1 gpm - we prefer that you keep flow through those these little carbon blocks at about 0.5 gpm max. Also - the typical booster pumps you're used to, the Aquatec 8800, won't work in this application. Commercial RO systems typically start at 500 gpd, and utilize a much larger electric motor and pump than you're used to seeing. For example:
And the prices jump considerably. Think in the $2000+ range. Ouch! So there is a gap between residential scale systems which typically top out at ~150 gpd, and commercial systems that typically start out at 500 gpd. We noticed this gap a number of years bag, and responded by designing The Gapper 400 gpd RO System:
https://www.buckeyehydro.com/the-gapper-light-commercial-ro-system/

At 400 gpd, The Gapper will produce almost 17 gallons per hour at a 1:1 ratio (if feedwater spec's are met). Rather than cobble together two 150 gpd membranes on a system designed to handle 150 gpd or less, The Gapper might be a good choice.

Russ

 

[Buckeye Hydro Verified Sponsor]

Perfectly in line with this conversation... I fielded a customer service call from a person with a brand name commercial RODI system configured for window washing. He's having all sorts of problems and the manufacturer hasn't been much help. I researched the system and found it had a 2500 gpd commercial membrane set to run at a 1:1 ratio. As prefilters, the system has a single 10" x 2.5" sediment filter, and a single 10" x 2.5" carbon block. So... using the logic I laid out above... What would be the feedwater flow through the apparently magic carbon block?
2500 gpd permeate + 2500 gpd concentrate = 5000 gpd feedwater flow
5000 gpd = 3.5 gallons per minute. Through a carbon block with a max allowable flow of 1 gpm. Hmmmmm.

This is some of the sort of stuff I think of every time I hear people say "All the RO systems on the market are all the same..."

Take home message? Be careful - there are loads of mis-configured systems out there on the market. Shop with a vendor who has demonstrated technical competence.

Russ

 

[ccoffel81]

Hi Guys - at 300 gpd permeate and a 4:1 ratio your feedwater would be at 1500 gpd, or 1.04 gpm. Realize that 10" x 2.5" carbon blocks have a max flow of 1 gpm - we prefer that you keep flow through those these little carbon blocks at about 0.5 gpm max..

Russ

If I add a membrane to the waste water line as a piggy back/water saver wouldn’t the water going through the prefilters be the same? No booster pump 70-75 psi at membrane 75ppm at membrane 1ppm after 800 capillary flow restrictor I said 1500 earlier was mistaken.

 

[Buckeye Hydro Verified Sponsor]

If I add a membrane to the waste water line as a piggy back/water saver wouldn’t the water going through the prefilters be the same? No booster pump 70-75 psi at membrane 75ppm at membrane 1ppm after 800 capillary flow restrictor I said 1500 earlier was mistaken.

Contrary to what you may have been told by a certain un-named vendor, running membranes in series on these low pressure systems is not ideal. So when you plumb two 75's in series for example, you have in effect just created a long 150 gpd membrane. Same thing with two 150's. So if you have 300 gpd worth of membrane, nothing says you can suddenly over restrict it by using a restrictor for a 150. You CAN do that, but unless you meet certain water quality limits for your feedwater, it's not a good idea. If you have soft water, you can get away with lots of things however.

 

[ccoffel81]

Contrary to what you may have been told by a certain un-named vendor, running membranes in series on these low pressure systems is not ideal. So when you plumb two 75's in series for example, you have in effect just created a long 150 gpd membrane. Same thing with two 150's. So if you have 300 gpd worth of membrane, nothing says you can suddenly over restrict it by using a restrictor for a 150. You CAN do that, but unless you meet certain water quality limits for your feedwater, it's not a good idea. If you have soft water, you can get away with lots of things however.

Thanks wasn’t told anything from anyone just doing my own research that’s why all info is welcome. Didn’t think about the pressure drop with added membrane. But having relatively soft water should help. Don’t want to buy whole new system just trying a cheaper route and wanting to save water.

 

[chipmunkofdoom2]

Don’t want to buy whole new system just trying a cheaper route and wanting to save water.

I would personally not upgrade the system if these are your goals. Tap water is just not that expensive. A 4:1 waste to product produces 4 gallons of waste and 1 gallon of product. A 2:1 ratio, the best you can hope to get by feeding the waste water from one membrane into another, wastes 2 gallons of water for every gallon of product produced. The average cost of tap water in the US is only $0.003/gallon. Translation: a 2 to 1 ratio saves you just over half a cent per gallon of product water produced.

I'm not saying that these savings wouldn't add up, but you really have to add up the costs to decide if this is worth it. Even if if you need 500 gallons of product water a month, a 2 to 1 waste to product only saves you three dollars a month in water costs. That's a long ROI time, especially if your system costs a few thousand dollars like the ones Buckeye linked.

 

[WVNed]

I have good source water. I already did it. I get 6 gallons an hour at 1:1. 80 psi in with no booster pump.

Yes I know. Doom will fall upon me. You already told me that

 

[ccoffel81]

I would personally not upgrade the system if these are your goals. Tap water is just not that expensive. A 4:1 waste to product produces 4 gallons of waste and 1 gallon of product. A 2:1 ratio, the best you can hope to get by feeding the waste water from one membrane into another, wastes 2 gallons of water for every gallon of product produced. The average cost of tap water in the US is only $0.003/gallon. Translation: a 2 to 1 ratio saves you just over half a cent per gallon of product water produced.

I'm not saying that these savings wouldn't add up, but you really have to add up the costs to decide if this is worth it. Even if if you need 500 gallons of product water a month, a 2 to 1 waste to product only saves you three dollars a month in water costs. That's a long ROI time, especially if your system costs a few thousand dollars like the ones Buckeye linked.

3$ here 3$ there when a person is at max on income it definitely adds up. A person has to figure everything when it comes to a tank e.g. power consumption fish food salt vitamins etc. I’m not a doctor, lawyer or insurance salesmen so I don’t have disposable income from overcharging people (sorry not to offend just raked over the coals by all three because you were all in the same bed together). My tank started out small through growth and my desire not to hurt living animals and have the best place for them to live I am at where I am now. Also I do a lot of water changes that’s the reasoning for 300 gallon a day not just price. Also thanks for the input. And I do roughly 6-700 gallons a month of ro.

 

[chipmunkofdoom2]

3$ here 3$ there when a person is at max on income it definitely adds up. A person has to figure everything when it comes to a tank e.g. power consumption fish food salt vitamins etc. I’m not a doctor, lawyer or insurance salesmen so I don’t have disposable income from overcharging people (sorry not to offend just raked over the coals by all three because you were all in the same bed together). My tank started out small through growth and my desire not to hurt living animals and have the best place for them to live I am at where I am now. Also I do a lot of water changes that’s the reasoning for 300 gallon a day not just price. Also thanks for the input. And I do roughly 6-700 gallons a month of ro.

Yes, $3 here and there adds up, and if you could snap your fingers and get the water savings for free, I'd absolutely recommend it. That's not the case though. The Gapper that Russ showed costs almost a thousand dollars. Even if you got the Gapper that Russ showed in his post and get a 1:1 ratio, you're still only saving $6.30/month over using a standard 4:1 ratio. And that's if you use 700 gallons a month. At a cost of $840, it'll take you over 10 years to get a return on your investment by only saving $6.30 a month. That also doesn't count the increased cost in filters, because the Gapper doesn't use the cheap 10" standard filters that most RO systems use. It might even use a nonstandard membrane. Hard to tell from the picture.

I'm not against people running dual membranes. I'm not against water systems with a low waste to product ratio. All of these things are fine and I'm not making a "good/bad" value judgement on any of them. These configurations even make sense if your chief goal is to produce water faster or save water for environmental reasons. I am against these things when done, whether in part or in whole, for financial reasons. The ROI just isn't there in most cases. Residential RO units like those provided by @Buckeye Hydro and Bulk Reef Supply are more than adequate for most hobbyists. Unless you have unusually dirty tap water, unusually expensive source water, or unusually high water demands, I don't think it makes a whole lot of financial sense to run advanced systems. Even if you need an advanced system because of one of these factors or because you want to be environmentally friendly, you're still not likely saving money.

 

[ccoffel81]

Yeah I don’t want or need an advanced system don’t even want a pump have pretty high pressure just want to add another membrane.

 

[lapin]

Yeah I don’t want or need an advanced system don’t even want a pump have pretty high pressure just want to add another membrane.

Just get a BRS kit. Add the membrane to the waste output of the first one and you are done. Its not like it will double your output of ro water but it will add some that normally would be sent down the drain or where ever. Im on rain water for my house. I do this so I can take showers in the summer.

 

[BZOFIQ]

Don't add one after the other. You're sending waste water to another membrane. That membrane will foul faster

Add in parallel with 2 separate restrictors. Russ please confirm if this is the way to go.

 

[KStatefan]

Don't add one after the other. You're sending waste water to another membrane. That membrane will foul faster

Add in parallel with 2 separate restrictors. Russ please confirm if this is the way to go.

With his low TDS water to begin with the TDS of the waste water being sent to the second will still be low.

 

[WVNed]

The BRS water saver kits have 75 and 100 gallon membranes. There is not a kit with a 150.
The 150 kit is for a second 75 gpd membrane to make 150gpd.

 

[KenO]

Why not just get 2 of the BRS systems? I started with a used BRS 75gpd system. I upgraded it to the dual 75 membranes. I added a booster pump and I can get over 200 gallons a day with a 1:1 waste. BTW I live in AZ where we have high TDS levels. Mine right now runs well over 650 TDS. I get 6 TDS out of my dual membranes. I do have a whole house water softener which does help the membranes. I also setup a 3 canister DI system. First is cation, anion and then the dual resin. Coming out of my anion resin the TDS is 0 before it goes into the dual DI resin canister. I live in the desert, and water, specifically low waste water is very important. I have my waste line run outside to water plants around the house.

Using standard RO/DI components would make more sense to me. Replacement parts are easy to get and cost effective. Plus if you have an issue with one system, you still have one that can make water vs having your whole system down. Just my thoughts......

 

[Buckeye Hydro Verified Sponsor]

Thanks wasn’t told anything from anyone just doing my own research that’s why all info is welcome. Didn’t think about the pressure drop with added membrane. But having relatively soft water should help. Don’t want to buy whole new system just trying a cheaper route and wanting to save water.

If all you're trying to do is cut down on the amount of concentrate ("waste water"), then just change your $4 flow restrictor. You certainly don't need to add a second membrane in series to do this.
Russ

 

[ccoffel81]

If all you're trying to do is cut down on the amount of concentrate ("waste water"), then just change your $4 flow restrictor. You certainly don't need to add a second membrane in series to do this.
Russ

Then I will have less ro Production. Want to save water and have more output that’s the reasoning for a second membrane as stated in earlier messages.

 

[Buckeye Hydro Verified Sponsor]

If you put in a tighter flow restrictor, you will have higher gauge pressure and MORE water production. Not as much as if you installed a second membrane.

I'd avoid adding a second membrane in series unless you use a flow restrictor that yields something around a 4:1 ratio (unless you have soft water).

Russ

 

[ccoffel81]

I will just state the question again wanting to know if anyone has ran to 150 gallon per day membranes? Wanting to add one to current system not purchase a Nother system a commercial system or anything like that thank you very much. Just wondering because that’s what I’m going to do is buy another membrane with fittings I have the proper flow restrictor.