TDS coming out is 30ppm.

[dmh41532]

So I recently hooked up a new ro unit with a meter, going in its 500, coming out its 30. Now our pressure is low, so I'll need to order a pump. Will increasing pressure help lower the tds in the clean water?

 

[TheHarold]

Sure a bit perhaps, but you really need a DI stage if you're using it for your tank

 

[dmh41532]

We have to use it for drinking too, which is why i didnt buy a ro/di. Is there a waybto add a di stage and bypass the di when we want drinking water?

 

[p7willm]

I use mine for drinking and the tank. When the water comes out of the final filter, or after the membrane if there is no final filter, put in a T. One leg goes to a drinking tank and the other goes to DI and then on to tank water storage. So you get both people and fish water.

 

[dmh41532]

My unit has a sediment filter first, then two carbon blocks. How would i add a di stage?

 

[p7willm]

Get either a single or dual DI stage, it gets used from the bottom up and if you have 2 you can use, get color changing resin to tell when it is used up, all of the first before changing the resin while with a single it will start having TDS before it is all used and you have to recharge then. The output of your current unit goes in to the DI.

If you want to also use it for drinking put a T in the line to the DI unit and take water from there for drinking.

I looked on BRS and they sell just DI stages, other places probably also sell them.

 

[AZDesertRat]

Follow this diagram a which shows how to isolate a drinking water pressure tank from the reef DI. Pay particular attention to the pavement of the check valve so the pressurized drinking water which contains TDS creep does not get to the DI resin and exhaust it.
http://spectrapure.com/huds/4-STAGE-DWK-RODI-NAG.pdf

30 is very high but I am assuming you are measuring out of the drinking water faucet or pressure tank and not directly from the RO membrane which is where you really need to measure. Pressure tanks and post RO carbons add TDS.

 

[dmh41532]

I have a dual in line meter, 30 is what was coming out of the membrane, i had to run it just a while ago and the tds coming out of the membrane was down to 15. Going in it was still 500. Ill check for the di resin. Can i use an standard canister for the di resin?

 

[AZDesertRat]

Yes a DI cartridge fits in a standard 10" canister.
15 is much better but will still exhaust a brand new DI cartridge in 150-200 gallons. Hopefully it gets better. My softened tap water TDS is 560 and my RO only TDS is between 2 and 3 so DI lasts a long time.

 

[morpheas]

When you say your pressure is low how low? That could be the key to this because membrane efficiency is highly dependent on pressure and temperature...

 

[dmh41532]

Im not sure of the exact pressure, i forgot to order a guage. But it comes out pretty slow, the minimun pressure to operate it is, 4opsi, so id guess its just above that.

 

[AZDesertRat]

You will get water out of the system below 40 psi, it just will not be filtered well.