How to make this rodi system better?

[christwendt]

I just moved and set up my upgraded rodi. It’s a 6 stage 200 gallon water saver brs. I make 5 gallons in 50 mins. I want to make it faster and more efficient if possible. The tds on the meter labeled “In” is 9 and out is obviously 0. And my psi pressure is 60. I would think if I could get the “In” number lower, my resin would last longer? My goal is to produce water faster, less water waste , and less often having to replace resin. I can provide Water report for location: also it’s a hardness of 6 grains it says on the water report.
Would a booster pump be my answer? Or another resin canister ?

 

[Opus]

You would benefit from a booster pump. The dual membrane setup minimum is 65psi. A pump should get you up to 90 or so for best efficiency and up your production. I produce around 5 gallons of water in about 90 minutes on my 90gpd setup. That should also lower your tds number. With your current number of 9 a di cartridge will produce around 500 gallons of 0 tds water. You have to understand thou your second RO membrane is being fed the waste water from the first RO membrane so it is a higher tds so its good water is going to be a higher number than your first membrane. Hard to say how good of a number your 9 is since you don't give the tds of your tap water.

 

[Woodyman]

You would benefit from a booster pump. The dual membrane setup minimum is 65psi. A pump should get you up to 90 or so for best efficiency and up your production. I produce around 5 gallons of water in about 90 minutes on my 90gpd setup. That should also lower your tds number. With your current number of 9 a di cartridge will produce around 500 gallons of 0 tds water. You have to understand thou your second RO membrane is being fed the waste water from the first RO membrane so it is a higher tds so its good water is going to be a higher number than your first membrane. Hard to say how good of a number your 9 is since you don't give the tds of your tap water.

Assuming tap water TDS is ~500 given a TDS of what I'm assuming is after the membrane of 9. A new membrane with rejection % around the standard 98% would put them around 500 for incoming.

Sound right OP? Have you checked your tap water TDS?

 

[Woodyman]

Might want to give this a read if your new to RO/DI Systems. It should answer a few of your questions, and then we can optimize your system for your goals.

RO/DI Basic Guide

There are always a lot of questions regarding which RO/DI setup do I need, how many stages, how do I know when to change filters/membranes, I’m getting a weird TDS value, etc. Hopefully this clarifies a few things and helps some of you out one day. My first recommendation would be to find the...

www.reef2reef.com

 

[christwendt]

Assuming tap water TDS is ~500 given a TDS of what I'm assuming is after the membrane of 9. A new membrane with rejection % around the standard 98% would put them around 500 for incoming.

Sound right OP? Have you checked your tap water TDS?

I have not checked my tap tds. Do I need to buy a tds meter then? Mines is built into my rodi.

 

[Woodyman]

I have not checked my tap tds. Do I need to buy a tds meter then? Mines is built into my rodi.

Not a requirement, but it's good to know. A handheld meter will be useful, but again not a requirement.

 

[SteveMM62Reef]

Install a Second RO Membrane, a pump will help a bit, but you are already at 60 psi, don’t go over 80 psi, a pressure spike above that setting can damage your RO. If you get a pump, making sure you get the pressure switch and matching transformer, there’s plenty of “Cheap Ones,” that don’t include these. Also a pre-strainer is a must for a pump. Checking your Municipal Water, is pretty much useless, as it will very by the hour. The highest Municipal TDS, is first thing in the morning, and around 6 pm. If you paid under $10 for your TDS Meter, it’s pretty useless after a couple of months. We had TDS Meters, at work, that cost over $200. They had replaceable tips. They are way beyond what you need for an Aquarium. A whole house filter will save your plumbing and RO/DI.

 

[Woodyman]

Install a Second RO Membrane, a pump will help a bit, but you are already at 60 psi, don’t go over 80 psi, a pressure spike above that setting can damage your RO. If you get a pump, making sure you get the pressure switch and matching transformer, there’s plenty of “Cheap Ones,” that don’t include these. Also a pre-strainer is a must for a pump. Checking your Municipal Water, is pretty much useless, as it will very by the hour. The highest Municipal TDS, is first thing in the morning, and around 6 pm. If you paid under $10 for your TDS Meter, it’s pretty useless after a couple of months. We had TDS Meters, at work, that cost over $200. They had replaceable tips. They are way beyond what you need for an Aquarium. A whole house filter will save your plumbing and RO/DI.

If you go the route of a second membrane you want it plumbed in parallel not in series with a TDS of ~500.

Also you can set a booster pump higher than 80, and honestly I'd say set it for ~90. RO membranes love pressure and will easily take 100+ psi. The problem is housings and fittings. Depending on the manufacturer they may not be rated for over 100. With BRS ones you will be fine to run at ~90 with no issues.

A second membrane and booster will improve your production time. You won't really reduce any waste water this way as you'll want yours in parallel, in series would reduce your waste to product ratio, but it will kill your membrane sooner on th 2nd RO with that high of an incoming TDS

 

[Woodyman]

Install a Second RO Membrane, a pump will help a bit, but you are already at 60 psi, don’t go over 80 psi, a pressure spike above that setting can damage your RO. If you get a pump, making sure you get the pressure switch and matching transformer, there’s plenty of “Cheap Ones,” that don’t include these. Also a pre-strainer is a must for a pump. Checking your Municipal Water, is pretty much useless, as it will very by the hour. The highest Municipal TDS, is first thing in the morning, and around 6 pm. If you paid under $10 for your TDS Meter, it’s pretty useless after a couple of months. We had TDS Meters, at work, that cost over $200. They had replaceable tips. They are way beyond what you need for an Aquarium. A whole house filter will save your plumbing and RO/DI.

Damage the RO housing? Yes if it's poorly made/defective.

Damage the membrane? No, not even close. The higher the pressure the more effective the membrane works.

 

[christwendt]

If you go the route of a second membrane you want it plumbed in parallel not in series with a TDS of ~500.

Also you can set a booster pump higher than 80, and honestly I'd say set it for ~90. RO membranes love pressure and will easily take 100+ psi. The problem is housings and fittings. Depending on the manufacturer they may not be rated for over 100. With BRS ones you will be fine to run at ~90 with no issues.

A second membrane and booster will improve your production time. You won't really reduce any waste water this way as you'll want yours in parallel, in series would reduce your waste to product ratio, but it will kill your membrane sooner on th 2nd RO with that high of an incoming TDS

I’m a little confused. My rodi system has two ro membranes as it came with it. So I should pretty much just get a booster to increase my PSI? 9 tds in just seems like a lot but it sounds like the booster will lower that more. I’m not sure what my tap tds is.

 

[christwendt]

You would benefit from a booster pump. The dual membrane setup minimum is 65psi. A pump should get you up to 90 or so for best efficiency and up your production. I produce around 5 gallons of water in about 90 minutes on my 90gpd setup. That should also lower your tds number. With your current number of 9 a di cartridge will produce around 500 gallons of 0 tds water. You have to understand thou your second RO membrane is being fed the waste water from the first RO membrane so it is a higher tds so its good water is going to be a higher number than your first membrane. Hard to say how good of a number your 9 is since you don't give the tds of your tap water.

That makes a lot of sense thank you for explaining all that. If I got 500 gallons off one cartridge of resin id be happy . I have two cartridges so that would be 1000 gallons. I’m not sure how much I can make so far off one cartridge because I just got the system. Good for reference to know tho. Will have to check my tap tds 500 just seems super high for my location. I’m very close to a huge city.

 

[Woodyman]

I’m a little confused. My rodi system has two ro membranes as it came with it. So I should pretty much just get a booster to increase my PSI? 9 tds in just seems like a lot but it sounds like the booster will lower that more. I’m not sure what my tap tds is.

The 9 your referring to is what feeds out of the membranes and into your first DI correct?

 

[Woodyman]

I’m a little confused. My rodi system has two ro membranes as it came with it. So I should pretty much just get a booster to increase my PSI? 9 tds in just seems like a lot but it sounds like the booster will lower that more. I’m not sure what my tap tds is.

My mistake I didn't know you already had 2.

In that case about the only thing you have control over would be pressure so a booster pump would do what you want as far as increasing the speed at which you produce permeate water.

 

[christwendt]

The 9 your referring to is what feeds out of the membranes and into your first DI correct?

I believe so. It’s the standard bulk reef supply 6 stage 200 gallon water saver. It has built in tds meter. I know the out is after DI as it reads zero and I would assume the “IN” after the ro membrane before the resin. I would think 9 going into my resin would cause me to burn through resin super fast.

 

[christwendt]

My mistake I didn't know you already had 2.

In that case about the only thing you have control over would be pressure so a booster pump would do what you want as far as increasing the speed at which you produce permeate water.

That’s what I was thinking and answers my post. Thank you. And if I go through resin fast then maybe adding another resin cartridge. I currently have 2

 

[Woodyman]

That’s what I was thinking and answers my post. Thank you. And if I go through resin fast then maybe adding another resin cartridge. I currently have 2

Adding resin won't reduce how frequently you go through it. Just how long before you have to replace them all. Personally I monitor each resin cartridge and when one is bad I replace. I don't wait until all 3 are gone. So adding an extra resin wouldn't change how frequently I replace the first resin cartridge it just gives me an extra backup for anything that misses the first cartridge.

 

[Opus]

I believe so. It’s the standard bulk reef supply 6 stage 200 gallon water saver. It has built in tds meter. I know the out is after DI as it reads zero and I would assume the “IN” after the ro membrane before the resin. I would think 9 going into my resin would cause me to burn through resin super fast.

You are probably correct on the reading. Yes, getting a handheld tds meter would be a good investment. Easy way to check to see how well your membranes are doing and also double check the built in meter. The cheap one from BRS or Amazon will be fine. I've had mine for over 10 years and it still works great. Bought a different brand and they both read the same. Also, as stated, higher pressure is better. I know people that run theirs over 100psi without issue. Only issue can be the murlock connectors but they are rated for 140psi I believe.

Once you have found out your tap tds, then you can test your membranes. To do it correctly you should test the good water coming out of the first membrane. Then check the tds of the waste water coming out of the first membrane that is feeding the second membrane. You then would need to check the good water coming out of the second membrane before it combines with the good water from the first membrane. Then calculate your rejection rate which should be around 98% or lower, though manufacturers only guarantee 95%. Take the good water divided by the bad water (in) and you should be around .02 or lower.

 

[Opus]

That’s what I was thinking and answers my post. Thank you. And if I go through resin fast then maybe adding another resin cartridge. I currently have 2

If you are worried about resin then you can go the route of splitting it out between cation and anion resins. You are running a mixed bed which just means the 2 are mixed together. They don't get used up at the same time. This way you only have to switch out which one gets used up first. You would need to add a third resin cartridge to your system. You would then have cation, then anion and then a mixed bed to catch anything the first 2 missed.

Another way to improve your tds is to buy better membranes. I use the Spectrapure membranes that guarantee 99% rejection rate. My tap tds is over 400 and my tds before di is usually between 3 and 4. The membranes should last 5 plus years.

 

[Woodyman]

If you are worried about resin then you can go the route of splitting it out between cation and anion resins. You are running a mixed bed which just means the 2 are mixed together. They don't get used up at the same time. This way you only have to switch out which one gets used up first. You would need to add a third resin cartridge to your system. You would then have cation, then anion and then a mixed bed to catch anything the first 2 missed.

Another way to improve your tds is to buy better membranes. I use the Spectrapure membranes that guarantee 99% rejection rate. My tap tds is over 400 and my tds before di is usually between 3 and 4. The membranes should last 5 plus years.

I can 2nd the Spectrapure that's where I get all my RO/DI stuff from.

 

[christwendt]

If you are worried about resin then you can go the route of splitting it out between cation and anion resins. You are running a mixed bed which just means the 2 are mixed together. They don't get used up at the same time. This way you only have to switch out which one gets used up first. You would need to add a third resin cartridge to your system. You would then have cation, then anion and then a mixed bed to catch anything the first 2 missed.

Another way to improve your tds is to buy better membranes. I use the Spectrapure membranes that guarantee 99% rejection rate. My tap tds is over 400 and my tds before di is usually between 3 and 4. The membranes should last 5 plus years.

So the membranes from them will be better than the brs ones it came with? I will have to get those when it’s time for new membranes. Mines are brand new. Thanks for the tip.