Well Water Chewing through DI Resin

[JordanM]

The information. ~300tds out of the well, 25tds after RO membrane and 0 TDS after two canisters DI resin. Booster pump is getting pressure to 90PSI measured between membrane and resin.
System is the 150GPD.
Problem: I just replaced the tow stages of DI resin and after only making about 50 gallons mi Resin is already depleted halfway up the first canister. Also noticed it looks like it only used a partial of the first canister and started consuming the second canister as you can see from the pictures. This is older resin in the first that has been regenerated a few times so maybe it has lost its color changing ability and the stuff that did change right at the beginning was the new stuff. What are your thoughts on the rapid consumption? CO2?

 

[cincyjim]

No idea actually. My only thought would be to send off a water sample to a water testing company and see what's in the water.

 

[flooddc]

I have seen discussions on "de-gas" (spelling?) your water before entering the DI.

 

[mcgyvr]

I'd start by investing in a higher rejection RO membrane..
Look into a 97-99%
That will reduce the TDS entering the DI and prolong its life..
Your current rejection rate is not good at all.

You should also check for CO2 as stated..
https://www.bulkreefsupply.com/carbon-dioxide-test-kit-lamotte.html
Or other test kits for it..

 

[ca1ore]

My first observation is that 25 after the RO is not that good. Means rejection rate is only at about 92%. It may be that your membrane needs replacing. You can buy 99% rejection rate ones that would lower TDS to 3-4 after the RO section. That will help enormously in extending the life of the DI resin. My system is similar, about 350 raw water, though only 5 after the RO. I also use dual DI canisters, and the first depletes after about 300 gallons.

My second observation is as already noted: CO2. Well water is notoriously high in CO@ which will reduce the life of the DI resin. Degassing the raw water is not a trivial undertaking, so I would go for a better membrane first and then see where you are.

 

[JordanM]

The membranes are about 5 years old and the dual 75gpd one from brs that are between 96-99% rejection. After about 18 hours the production is only about 50 gallons so it seems this is really lacking as well.

 

[mcgyvr]

The membranes are about 5 years old and the dual 75gpd one from brs that are between 96-99% rejection. After about 18 hours the production is only about 50 gallons so it seems this is really lacking as well.

They are clearly in need of replacement..
Typically membranes last 3-5 years and the rejection rate shows its basically done..

 

[JordanM]

Should i also add a flush valve if i replace both the 75gpd membranes? Right now it just has the restrictor. Does the flush valve just replace the restrictor and serve both purposes?
https://www.bulkreefsupply.com/membrane-flush-valve.html

 

[mcgyvr]

Flush valves like that have the restrictor built into them so yes you would remove the restrictor you have an replace it with that..

 

[ca1ore]

As noted, membrane(s) are shot. That you are not getting the volume you expect either means you have a water pressure problem, the wrong size restrictor or something is clogged. I typically replace the pre-filters annually and the membrane every 3 years, or when the rejection rate gets worse.

 

[Opus123]

At your current tds of 25, a DI cartridge will make around 175 gallons of 0 TDS water. If you replace your RO membranes with the 99% rejection rate you should be getting around 3 TDS which should get you around 1475 gallons of 0 TDS water from a DI cartridge. This is assuming you don't have a CO2 problem.

 

[JordanM]

Im going to go ahead and order two of the 75gpd membranes and a new flush/restrictor. Im also thinking about changing one of the carbon blocks to another sediment filter and the other carbon block to a silicabuster before going into the dual di canister. This does have a booster pump on it as well so im getting 90psi between the membrane and the resin.

So my layout will be booster pump to 5um sediment filter to 1um sediment filter to dual 75gpd membranes to silicabuster to dual di resin chambers. The waste i will change to a flush valve/ restrictor since it is the same price for just a restrictor anyways.

Are there any other suggestions? When i get home i will test ph and bubble it for awhile and see if the ph changes. How long should i bubble it for before testing again?

 

[alton]

From Spectrapure

 

[JordanM]

That is interesting. When spectrapure says 99% rejection is that a true number or can there be a range? I know BRS specifies theres will be between 96-99% rejection.

 

[mcgyvr]

That is interesting. When spectrapure says 99% rejection is that a true number or can there be a range? .

Typical stabilized conductivity rejection 99%, minimum conductivity rejection 98%.
98-99%

Footnote 1: Permeate flow and conductivity rejection based on 250 ppm, 77°F (25°C) softened water feed, 15% recovery and the specified applied pressure.

 

[JordanM]

Typical stabilized conductivity rejection 99%, minimum conductivity rejection 98%.
98-99%

Footnote 1: Permeate flow and conductivity rejection based on 250 ppm, 77°F (25°C) softened water feed, 15% recovery and the specified applied pressure.

So, basically these filters are better than 2% tighter range then the Dow filmtec ones but are double the price.

 

[mcgyvr]

So, basically these filters are better than 2% tighter range then the Dow filmtec ones but are double the price.

yep...
Decision is yours.. (and of course minor math looking at potential DI savings with that added cost answers that decision with relative easy)

You may pay twice the membrane price but save 4 times the DI cost over the lifespan of the membrane..

 

[JordanM]

yep...
Decision is yours.. (and of course minor math looking at potential DI savings with that added cost answers that decision with relative easy)

You may pay twice the membrane price but save 4 times the DI cost over the lifespan of the membrane..

Are you able to run two of these filters in parallel like the brs 150gpd ones that use two 75gpd membranes?

 

[mcgyvr]

Are you able to run two of these filters in parallel like the brs 150gpd ones that use two 75gpd membranes?

They are just like any other membrane.. Just higher rejection rate..

 

[JordanM]

So what restrictor would you use for the dual unit since they both connect back into the same waste line and use one restrictor? Would it be safe to go with what BRS does and just use the 150gpd restrictor which is 800mL?