High TDS/DI usage

[Stopher.Stevens]

Here's the short version. I'm running a Air, Water and Ice Typhoon unit ... 5 stages. Sediment, Carbon block 5 micro, carbon block 1 micron, DUAL 75 GPD membranes into a 10" DI canister. I'm also using a booster pump as my well lacks sufficient pressure to make water correctly.

I have a well. My TDS out of the tap is 700+ on a good day. I'm currently 50ish before DI and using DI like CRAZY. What can I do to resolve my DI usage. I can make 50 gallons of 0 TDS water before a 10" canister is exhausted.

I rent my home so a whole house water softener is out of the question.

Any thoughts are appreciated.

 

[reeferfoxx]

You would probably need two membranes and 3 DI's in addition to the carbon and sediment block.

 

[TheEngineer]

You might have high CO2 in your well water also. 50ppm will deplete your DI fairly quick as well.

 

[Stopher.Stevens]

You would probably need two membranes and 3 DI's in addition to the carbon and sediment block.

I'm running 2 membranes currently, from my understanding it doesn't decrease TDS just water usage. I'm not concerned with the amount of water I use.

 

[reeferfoxx]

I'm running 2 membranes currently, from my understanding it doesn't decrease TDS just water usage. I'm not concerned with the amount of water I use.

Membranes reduce a lot. Two membranes is the right path. You would need more DI's.

 

[Stopher.Stevens]

Membranes reduce a lot. Two membranes is the right path. You would need more DI's.

I'm trying to avoid that ... At this point I can just swap out the DI cartridge once it's exhausted. What would be the benefit to having more than one DI?

 

[Stopher.Stevens]

You might have high CO2 in your well water also. 50ppm will deplete your DI fairly quick as well.

I've never heard of that? Any way to test it?

 

[reeferfoxx]

I've never heard of that? Any way to test it?

Membranes are designed to remove ions, molecules and large particles. If it didn't do any of that, I wouldn't quite understand the point in having them? You can test TDI after any export of the RO/DI unit. Just disconnect in front of the next stage.

@AZDesertRat used to be the RO guru if he is still around?

 

[Stopher.Stevens]

Membranes are designed to remove ions, molecules and large particles. If it didn't do any of that, I wouldn't quite understand the point in having them? You can test TDI after any export of the RO/DI unit. Just disconnect in front of the next stage.

@AZDesertRat used to be the RO guru if he is still around?

I know how to test my membranes effectiveness ... I was referring to the co2 in the well.

 

[TheEngineer]

I've never heard of that? Any way to test it?

You can do a bubble test to see or you can get a CO2 test kit.

 

[reeferfoxx]

I know how to test my membranes effectiveness ... I was referring to the co2 in the well.

Oops sorry!

 

[TheEngineer]

The bubble test is just measuring pH really. Take some water from your well and test the pH. If it is low, good chance you have high CO2. Take the sample outside and run an airstone in it for an hour. If the pH goes back to normal you have high CO2.

 

[redfishbluefish]

A quality membrane should be giving you 98% or better reduction in TDS. You're 700 TDS in, 50 out is about 93 percent. I'm no expert, but maybe @AZDesertRat can add in something.

You can do a pH test for CO2. Measure pH right from the tap. Let it sit overnight or bubble it. Measure pH again. High CO2 water will be acidic, while after allowing it to de-gas, will be closer to pH7.

 

[Stopher.Stevens]

Oops sorry!

no worries

 

[Stopher.Stevens]

The bubble test is just measuring pH really. Take some water from your well and test the pH. If it is low, good chance you have high CO2. Take the sample outside and run an airstone in it for an hour. If the pH goes back to normal you have high CO2.

I knew I didn't throw out that PH test kit for a reason ... Thanks.

 

[redfishbluefish]

Although you are questioning the presence of CO2 (which will eat through DI in no time), it's that 50 TDS out of the RO that's going to chew up DI very quickly. I'd surmise the major problem is that high TDS after RO. FYI, CO2 doesn't show up as TDS.

 

[TheEngineer]

Although you are questioning the presence of CO2 (which will eat through DI in no time), it's that 50 TDS out of the RO that's going to chew up DI very quickly. I'd surmise the major problem is that high TDS after RO. FYI, CO2 doesn't show up as TDS.

Agreed. In my case though, I can go through an entire DI cartridge after 15 gallons of water through it due to high CO2. Don't know how fast the OP is running through.

 

[Stopher.Stevens]

Agreed. In my case though, I can go through an entire DI cartridge after 15 gallons of water through it due to high CO2. Don't know how fast the OP is running through.

1 - 10" cannister lasts approx 50 gallons. I've got 3 tanks with a total volume of 600 gallons ... It gets expensive FAST making 0 TDS water.

 

[skim]

Here's the short version. I'm running a Air, Water and Ice Typhoon unit ... 5 stages. Sediment, Carbon block 5 micro, carbon block 1 micron, DUAL 75 GPD membranes into a 10" DI canister. I'm also using a booster pump as my well lacks sufficient pressure to make water correctly.

I have a well. My TDS out of the tap is 700+ on a good day. I'm currently 50ish before DI and using DI like CRAZY. What can I do to resolve my DI usage. I can make 50 gallons of 0 TDS water before a 10" canister is exhausted.

I rent my home so a whole house water softener is out of the question.

Any thoughts are appreciated.

Just a couple of questions. Do you flush the membranes at all? Do you bypass the first few gallons of water to lower TDS before running to the DI?
Do you know what kind of pressure your are getting to the membranes as with 700 tds well water your Pre filters are more than likely glogging quickly and lowering your psi.

 

[TheEngineer]

I have to look this up every time this question comes up... I'm going to finally put this on my website so I don't have to keep searching for it.

A standard vertical DI canister has the capacity to remove approximately 6800ppm of TDS. So if you are getting 50ppm out of your RO, your cartridge should give you 136 gallons of 0 TDS water. The actual capacity varies by the type of DI resin, but this is a good approximation. That leads me to think this is a combination of higher than expected TDS from your RO membrane as @redfishbluefish said and another contributing factor, possibly CO2.