RO/DI Help!

[Topreefer92]

Hey All,

I wanted to reach out as I have been having some issues with TDS being around the 18-19 range before going into the resin cartridge. My specific setup up is the BRS 4-Stage system with the 150 gal per day upgrade. So a sediment filter, 1 um carbon block, 2 75 gallon per day RO membranes and then a single bed color changing DI resin. The 18-19 range was measured about 4 hours after I replaced both RO membranes. The Carbon block and sediment filter have not been changed in a while and wanted your opinions. Will changing out the carbon block and the sediment filter bring that down significantly before the resin cartridge or do I need some additional filtering beyond what I have along with replacing the CB and Sediment filter.

Thank you all for your time!

 

[KStatefan]

The carbon block is what protects the membrane. If you carbon block was used up the chlorine will get thru and ruin the membrane.

 

[Topreefer92]

Alright I will replace that as well, I noticed that only 1 ro membrane was dirty and the secondary wasn't when i replaced them with brand new ones.

 

[Water Dog]

What is the TDS of your tap water? Those dual RO membrane setups are not the most efficient if you have very high TDS source water to begin with.

 

[KStatefan]

I replace my carbon block about every 6 months and my membrane is going on 3 years old. How often you replace the prefilters depends on how much water you use and how your water source is treated. Carbon block will not last as long with chloramines being used.

 

[Topreefer92]

What is the TDS of your tap water? Those dual RO membrane setups are not the most efficient if you have very high TDS source water to begin with.

My tds coming from the tap is around 375, 400. I was wondering that as when I replaced the membranes one was really dirty and the second one looked brand new.

 

[Topreefer92]

I replace my carbon block about every 6 months and my membrane is going on 3 years old. How often you replace the prefilters depends on how much water you use and how your water source is treated. Carbon block will not last as long with chloramines being used.

I need to call them and see if they started to use chloramines. That is a good change cycle you have I don't think I do that even. My fault on that but i just was curious if i should add additional stages to the system if that is necessary.

 

[aquaman99]

My tds coming from the tap is around 375, 400. I was wondering that as when I replaced the membranes one was really dirty and the second one looked brand new.

I have very similar TDS from the tap. Mine is actually 465 from the tap. I get consistantly 25-35 TDS after the RO stage. Check your pressure. I have a feeling that might be your issue. I had to buy a new garden hose to get my TDS down to single digits before it goes into the DI resin. But I decided to just upgrade to a custom 7 stage. I'm putting it together today.

 

[Topreefer92]

Pressure is around 85-90 consistantly, what will replacing the garden hose do? What filters and such do you have on that customer 7 stage? Sounds pretty awesome. BRS has the upgrade kit for mine to make it a 6 stage which I think is awesome.

 

[Water Dog]

My tds coming from the tap is around 375, 400. I was wondering that as when I replaced the membranes one was really dirty and the second one looked brand new.

Quite frankly, with a source water TDS that high, I would get rid of the “water saver” second membrane of your RODI unit. With a 98% rejection rate, using a single membrane you should be getting around 8 tds post the first RO stage. You’re putting super hi TDS wastewater into the second membrane and increasing the TDS of your post second membrane RO product water. Doing the math, your numbers seem right. So essentially, you’re severely shortening the lifespan of that second RO membrane, getting higher TDS post the RO stages product water and thereby severely shortening the life of your DI resin.

Take a look at around 4:30 of this BRS video. The water saver add on isn’t teally a good choice for high TDS source water applications IMO. You’re be better served spending the money on quality prefilters to protect your RO membrane and perhaps using Spectrapure’s 99% rejection rate membrane.

 

[Topreefer92]

Quite frankly, with a source water TDS that high, I would get rid of the “water saver” second membrane of your RODI unit. With a 98% rejection rate, using a single membrane you should be getting around 8 tds post the first RO stage. You’re putting super hi TDS wastewater into the second membrane and increasing the TDS of your post second membrane RO product water. Doing the math, your numbers seem right. So essentially, you’re severely shortening the lifespan of that second RO membrane, getting higher TDS post the RO stages product water and thereby severely shortening the life of your DI resin.

Take a look at around 4:30 of this BRS video. The water saver add on isn’t teally a good choice for high TDS source water applications IMO. You’re be better served spending the money on quality prefilters to protect your RO membrane and perhaps using Spectrapure’s 99% rejection rate membrane.

I appreciate the in sight I thought the secondary membrane would help produce more water and less waste water but I will try running just one filter. Sucks that if i go that route i just wasted a brand new memebrane.

 

[Potatohead]

I appreciate the in sight I thought the secondary membrane would help produce more water and less waste water but I will try running just one filter. Sucks that if i go that route i just wasted a brand new memebrane.

You can run them in parallel rather than in series, but in that case you'll probably want another DI canister. You'll make water twice as fast though.

 

[Water Dog]

You can run them in parallel rather than in series, but in that case you'll probably want another DI canister. You'll make water twice as fast though.

That’s a good call as to not waste the gear you’ve already bought. Just note you’ll need a second flow restrictor as well.

 

[fourdrachma]

I purchased an additional large capacity carbon filter at Lowe’s, and plumbed it in before it enters my RO system...made a lot of difference, and added protection for my RO membrane...

 

[Topreefer92]

So many good ideas you all have I need to figure out how to run them in parallel because I thought the series setup seemed off

 

[Opus]

I appreciate the in sight I thought the secondary membrane would help produce more water and less waste water but I will try running just one filter. Sucks that if i go that route i just wasted a brand new memebrane.

Look at it this way. If you upgraded to a spectrapure 99% rejection rate membrane and got down to 4 tds you would make up for the extra upfront cost in DI savings over time. At your current 18 tds, a DI catridge will make around 250 gallons of 0 tds water. At 4 tds a DI cartridge will make around 1100 gallons of 0 tds water.

My water runs between 400 and 450 tds and I get 3 to 4 tds after my spectrapure RO membrane.

 

[Opus]

I purchased an additional large capacity carbon filter at Lowe’s, and plumbed it in before it enters my RO system...made a lot of difference, and added protection for my RO membrane...

How did it make an difference? All the carbon does is remove chemicals, it does nothing for tds.

 

[Topreefer92]

I will look at replacing in the future with spectrapure since they are based here, always just went with BRS recommendation.

 

[Topreefer92]

Look at it this way. If you upgraded to a spectrapure 99% rejection rate membrane and got down to 4 tds you would make up for the extra upfront cost in DI savings over time. At your current 18 tds, a DI catridge will make around 250 gallons of 0 tds water. At 4 tds a DI cartridge will make around 1100 gallons of 0 tds water.

My water runs between 400 and 450 tds and I get 3 to 4 tds after my spectrapure RO membrane.

@waterdog, are you running one our two of those membranes?


Literally though the dow and the spectrapure membranes look identical, same color l, design just with a different sticker on them.

 

[Water Dog]

@waterdog, are you running one our two of those membranes?

I run a single Spectrapure 99% rejection rate membrane. My Tap TDS is 67. Post RO is 0 TDS. Needless to say, my Spectrapure MaxCap and SilicaBuster DI resin cartridges las forever.

However, you quoted @Opus and I believe he runs a single Spectrapure 99% rejection rate membrane as well.