RODI reading 13 ppm

[STEVEN ADAMS]

just added a new tlc100 membrane. before water was reading 22 ppm. added this one and now I am reading 13 ppm after 10 mins of letting the system run. will it increase the longer I run the system? Also I replaced sediment filter and carbon block one week ago. I only have one carbon block btw. tap water reads 350. No DI resin hooked up yet. is 13 ppm good? from what I was seeing systems should read 1-2 before the DI resin?

 

[KStatefan]

What is the incoming water TDS?

 

[mfinn]

What is the incoming water TDS?

he said it's 350

 

[mfinn]

just added a new tlc100 membrane. before water was reading 22 ppm. added this one and now I am reading 13 ppm after 10 mins of letting the system run. will it increase the longer I run the system? Also I replaced sediment filter and carbon block one week ago. I only have one carbon block btw. tap water reads 350. No DI resin hooked up yet. is 13 ppm good? from what I was seeing systems should read 1-2 before the DI resin?

Did you get the same brand membrane this time as what came with the rodi unit originally?
The reason I ask is if you switched brands, you may need a different flow restrictor?
Plus depending on websites, some recommend a hour or two or longer to flush a new membrane.

 

[KStatefan]

What rejection rate is the membrane rated at? You are getting about 96% at 13 ppm.

 

[chipmunkofdoom2]

from what I was seeing systems should read 1-2 before the DI resin?

This is not correct. How much the reverse osmosis membrane removes depends upon the source water TDS as well as the specific solids in the water. Some solids are easily removed by an RO membrane, while others are not. In general, most RO membranes will give you a 96% rejection rate. If your tap water is 350ppm TDS and the water after the membrane is 13ppm TDS, then your rejection rate is around 96%. What specific membrane did you order? In general, 100GPD membranes (which it sounds like you bought) don't have the greatest rejection rates and you might be able to do better with a 75GPD membrane. I would personally not replace the membrane now though. It's working fine. Maybe just consider a 75GPD for your next membrane.

You asked if 13ppm TDS is "good." This depends on how you plan to use the water. If you're drinking the water, yes, 13ppm TDS is much better than your initial tap water's 350ppm TDS. In my opinion, this water is not well-suited for a reef tank with sensitive invertebrates. You should run this water though a DI stage before using it on a reef tank. There are many ions that are particularly problematic to reef tanks that are handled only by DI resin. Among those is copper, ammonia as ammonium, phosphates and silicates. These ions may be present in high concentrations in reverse osmosis filtered water.

 

[STEVEN ADAMS]

the membrane I bought is called pentair. It is a different brand than the previous one. I got the RO system used from the previous tank owner and am unsure of the original membrane. I have the DI resin. I have yet to hook it up. Do you guys think it will be enough to get my TDS to 0? I have considered adding a second carbon filter too.

 

[STEVEN ADAMS]

This is not correct. How much the reverse osmosis membrane removes depends upon the source water TDS as well as the specific solids in the water. Some solids are easily removed by an RO membrane, while others are not. In general, most RO membranes will give you a 96% rejection rate. If your tap water is 350ppm TDS and the water after the membrane is 13ppm TDS, then your rejection rate is around 96%. What specific membrane did you order? In general, 100GPD membranes (which it sounds like you bought) don't have the greatest rejection rates and you might be able to do better with a 75GPD membrane. I would personally not replace the membrane now though. It's working fine. Maybe just consider a 75GPD for your next membrane.

You asked if 13ppm TDS is "good." This depends on how you plan to use the water. If you're drinking the water, yes, 13ppm TDS is much better than your initial tap water's 350ppm TDS. In my opinion, this water is not well-suited for a reef tank with sensitive invertebrates. You should run this water though a DI stage before using it on a reef tank. There are many ions that are particularly problematic to reef tanks that are handled only by DI resin. Among those is copper, ammonia as ammonium, phosphates and silicates. These ions may be present in high concentrations in reverse osmosis filtered water.

I plant to use the water with my reef. I have been doing my water changes with TDS water at around 30 ppm.

 

[mfinn]

the membrane I bought is called pentair. It is a different brand than the previous one. I got the RO system used from the previous tank owner and am unsure of the original membrane. I have the DI resin. I have yet to hook it up. Do you guys think it will be enough to get my TDS to 0? I have considered adding a second carbon filter too.

The di resin will take it to 0 TDS, but you going to find it uses it pretty fast.

 

[STEVEN ADAMS]

The di resin will take it to 0 TDS, but you going to find it uses it pretty fast.

Anything I can do to help? and how fast would you expect?

 

[Buckeye Hydro Verified Sponsor]

The TLC-100 is spec'ed at 98% rejection at 65 psi. We don't like those pentair membranes because a better product is available at a lower cost that requires less pressure - the Filmtec 100 gpd membrane.

What is your water pressure at the membrane?

Check your waste water to purified water ratio to see if you have the correct flow restrictor installed. Let me know if you're unclear as to how to easily check this.

At 13 ppm, assuming you don't have other complications (e.g., CO2, chloramines), you might get about 350+ gallons from a 10" x 2.5" DI cartridge.

Russ

 

[STEVEN ADAMS]

The TLC-100 is spec'ed at 98% rejection at 65 psi. We don't like those pentair membranes because a better product is available at a lower cost that requires less pressure - the Filmtec 100 gpd membrane.

What is your water pressure at the membrane?

Check your waste water to purified water ratio to see if you have the correct flow restrictor installed. Let me know if you're unclear as to how to easily check this.

At 13 ppm, assuming you don't have other complications (e.g., CO2, chloramines), you might get about 350+ gallons from a 10" x 2.5" DI cartridge.

Russ

I have a pressure gauge coming in the mail. how can I check my waste to purified water rartio? I would say water definitely comes out of the purified a little bit faster than the waste side. not by a lot.

 

[STEVEN ADAMS]

The TLC-100 is spec'ed at 98% rejection at 65 psi. We don't like those pentair membranes because a better product is available at a lower cost that requires less pressure - the Filmtec 100 gpd membrane.

What is your water pressure at the membrane?

Check your waste water to purified water ratio to see if you have the correct flow restrictor installed. Let me know if you're unclear as to how to easily check this.

At 13 ppm, assuming you don't have other complications (e.g., CO2, chloramines), you might get about 350+ gallons from a 10" x 2.5" DI cartridge.

Russ

for my next membrane one of the other users suggested a 75 gpd would I be better off finding a 75 filmtec?

 

[Buckeye Hydro Verified Sponsor]

I have a pressure gauge coming in the mail. how can I check my waste to purified water rartio? I would say water definitely comes out of the purified a little bit faster than the waste side. not by a lot.

You should have "waste water" coming out 4 times as fast as the purified water. If you have soft water you can get away with a 2:1.

Line up 8 identical cups in front of the system. With your waste water tube in one hand and your purified water tube in the other, how many glasses do you fill with waste water in the time it takes you to fill one with purified?

 

[Buckeye Hydro Verified Sponsor]

You can expect a slightly higher (1% higher) rejection with a 75 Filmtec (99%) than a 100 Filmtec (98%). But you'll have slightly slower production. Make sure to always match your flow restrictor such that you get than 4:1 ratio.

http://www.buckeyehydro.com/residential-ro-membranes/

http://www.buckeyehydro.com/capillary-flow-restrictors/

 

[mfinn]

When I need to measure waste vs. product water I use a 1 gallon container for the product water and a 5 gallon bucket for the waste.
Let the rodi run for a few minutes, then add both lines to their respective containers at the same time.
When the 1 gallon product water fills, remove both lines and measure the amount of water in the 5 gallon bucket, using the same container ( or a identical container) as that was used for the product water.

 

[STEVEN ADAMS]

I bought one of the flush valve/ flow restictor from BRS what do I do with it?

 

[Buckeye Hydro Verified Sponsor]

Feel free to give us a call when you are in front of your system.

Russ
513-312-2343

 

[STEVEN ADAMS]

Feel free to give us a call when you are in front of your system.

Russ
513-312-2343

TDS lowered to 3 now. using inline tds meter

 

[mfinn]

TDS lowered to 3 now. using inline tds meter

Is that right from the ro membrane?