DI Resin

[Chameleon]

Just trying to get a feel for what DI resins everyone is using these days. I've been using the standard mixed bed from Spectrapure, but feel it gets depleted rather fast for the low TDS water going in and the amount of water I make. Thinking of switching it up to the superDI.

 

[AZDesertRat]

Super SilicaBuster. It is designed specifically for reef use unlike normal mixed bed resins and has about 30-35% greater capacity for only a couple $$ more.
You say "low TDS", what specifically are your tap water and RO only water TDS readings? Do you know if you might have CO2 present in your water? CO2 affects resin life and does not show up as TDS so can go undetected but can be tsetd for or estimated.
How do you make your RO/DI water, short frequent filter runs such as with a float valve or longer, less frequent filter runs by making full batches either manually or using something like float switches set a distance apart so the RO doesn't start and stop frequently leading to TDS creep and a clogged or fouled membrane.

 

[Randy Holmes-Farley Verified Community Expert]

I use the DI resin from BRS.

What is your TDS entering the resin and how much water do you appear to get from it?

 

[Chameleon]

I use the DI resin from BRS.

What is your TDS entering the resin and how much water do you appear to get from it?

Last time I checked is was 5 post RO and I estimate between 300-400 gallons produced.
I should test post RO again, its been a while...maybe the RO is going bad, but it is a bit tricky for me to get to that connection on my system to take a sample.

BTW into the RO is between 110-130 every time I test

 

[Chameleon]

Super SilicaBuster. It is designed specifically for reef use unlike normal mixed bed resins and has about 30-35% greater capacity for only a couple $$ more.
You say "low TDS", what specifically are your tap water and RO only water TDS readings? Do you know if you might have CO2 present in your water? CO2 affects resin life and does not show up as TDS so can go undetected but can be tsetd for or estimated.
How do you make your RO/DI water, short frequent filter runs such as with a float valve or longer, less frequent filter runs by making full batches either manually or using something like float switches set a distance apart so the RO doesn't start and stop frequently leading to TDS creep and a clogged or fouled membrane.

Cool I'll look into that

 

[AZDesertRat]

To make TDS testing easier I installed a tee and ball valve between the RO and the DI so I can draw samples for my handheld TDS meter. It was a pain always disconnecting the lines or having to rely on the dual inline TDS meters which are only ballpark close at best. I have dual DI so I also installed a teen and ball valve between the two so I can test each DI by itself too.

 

[Chameleon]

To make TDS testing easier I installed a tee and ball valve between the RO and the DI so I can draw samples for my handheld TDS meter. It was a pain always disconnecting the lines or having to rely on the dual inline TDS meters which are only ballpark close at best. I have dual DI so I also installed a teen and ball valve between the two so I can test each DI by itself too.

great idea

 

[Randy Holmes-Farley Verified Community Expert]

Last time I checked is was 5 post RO and I estimate between 300-400 gallons produced.
I should test post RO again, its been a while...maybe the RO is going bad, but it is a bit tricky for me to get to that connection on my system to take a sample.

BTW into the RO is between 110-130 every time I test

My TDS into the RO is about 9. I don't keep track of the exact amount of water I get, but I think it is a bit more than you get.

Are you packing it tightly?

 

[Chameleon]

My TDS into the RO is about 9. I don't keep track of the exact amount of water I get, but I think it is a bit more than you get.

Are you packing it tightly?

I assume you mean out of the RO as 9 in would be excellent tap water? I haven't ever packed a DI cartridge and have always purchased them pre-packed from spectrapure. Although this last one the resin seemed to shift around more than normal over time. Maybe it was factory packed slightly low.

 

[Randy Holmes-Farley Verified Community Expert]

I assume you mean out of the RO as 9 in would be excellent tap water? I haven't ever packed a DI cartridge and have always purchased them pre-packed from spectrapure. Although this last one the resin seemed to shift around more than normal over time. Maybe it was factory packed slightly low.

My tap is about 100 ppm TDS and my post RO is about 9. Post DI#1 is 0 ppm TDS unless I let it deplete.

Prepacked is good. It is jsut that if you loosely pack a DI, yourself, water can channel through and you don't use it all effectively.

FWIW, the TDS is not a perfect measure of how long a DI will last, since it will vary a bit with what is actually in the water.

 

[Chameleon]

My tap is about 100 ppm TDS and my post RO is about 9. Post DI#1 is 0 ppm TDS unless I let it deplete.

Prepacked is good. It is jsut that if you loosely pack a DI, yourself, water can channel through and you don't use it all effectively.

FWIW, the TDS is not a perfect measure of how long a DI will last, since it will vary a bit with what is actually in the water.

I'm thinking its time to replace the 60 year old galvanized half inch pipes on this old house Thanks for the insight, I didn't think about TDS being a poor way to gauge the length your DI should last but you are absolutely right.

 

[yellojello]

My tap is about 100 ppm TDS and my post RO is about 9. Post DI#1 is 0 ppm TDS unless I let it deplete.

Prepacked is good. It is jsut that if you loosely pack a DI, yourself, water can channel through and you don't use it all effectively.

FWIW, the TDS is not a perfect measure of how long a DI will last, since it will vary a bit with what is actually in the water.

100 TDS to 9 TDS RO seems the Membrane needs replacing, or you are using a very inefficient membrane or high GPD system. Using the original membrane that came with my 100 GPD unit, I was getting about 96% rejection rate from 350 - 375 TDS to about 14 - 16 TDS RO. After switching to the Spectrapure 99% rejection membrane, it's down to 6 - 7 TDS RO, albeit makes water a little slower using a different flow restrictor to adjust to the membrane's specs.

 

[Randy Holmes-Farley Verified Community Expert]

100 TDS to 9 TDS RO seems the Membrane needs replacing, or you are using a very inefficient membrane or high GPD system. Using the original membrane that came with my 100 GPD unit, I was getting about 96% rejection rate from 350 - 375 TDS to about 14 - 16 TDS RO. After switching to the Spectrapure 99% rejection membrane, it's down to 6 - 7 TDS RO, albeit makes water a little slower using a different flow restrictor to adjust to the membrane's specs.

It was always that way, given to me by Spectrapure. My water has a number of things that get through RO membranes fairly readily (silicate and ammonia from chloroamine, for example).

 

[Chameleon]

Well I found my issue...post RO is 24 TDS. This membrane was replace a year ago. What can cause a membrane to go bad that fast? I replace prefilters every 6 months on the mark with Spectrapure 1uM value pack (sediment and carbon).

 

[Randy Holmes-Farley Verified Community Expert]

Maybe it needs to be reseated against the seals, and water is leaking around it.

 

[Chameleon]

Maybe it needs to be reseated against the seals, and water is leaking around it.

Good thought, Ill try resetting it. I was also thinking maybe an occluded restrictor line may cause this...does this mean I need to go calculate my brine to RO water ratio again...not fun.

 

[Rjramos]

Well I found my issue...post RO is 24 TDS. This membrane was replace a year ago. What can cause a membrane to go bad that fast? I replace prefilters every 6 months on the mark with Spectrapure 1uM value pack (sediment and carbon).

Don't know if you do?, but always remember when changing sediment and carbon filters to disconnect tubing from 2nd carbon to RO membrane and flush out, otherwise you get carbon sediment on your membrane.

 

[Chameleon]

Don't know if you do?, but always remember when changing sediment and carbon filters to disconnect tubing from 2nd carbon to RO membrane and flush out, otherwise you get carbon sediment on your membrane.

hmmm I have never done that...oops..i've only replaced 1 or two membranes though

 

[Rjramos]

hmmm I have never done that...oops..i've only replaced 1 or two membranes though

Next time. The first water that comes out is dark gray, then gets lighter. Flush until you get clear water, then reconnect tubing to membrane.