RODI help

reefertank · May 17, 2018

So bought a used aquafx 100 gpd rodi, I replaced all of the filter and resin. So here is the problem it goes through 2 di filters and I have made about 100 gallons and they are already turning orange. Also see the sediment filter is turning orange as well. Is this normal, also my TDS meter is reading 4 when the water comes out. My psi is 60, my tap water going in is reading 258 on the TDS meter.

cmcoker · May 17, 2018

A TDS of 4 shouldn't burn through di resin that quick. Assuming the rain was fresh and properly packed you may be dealing with high CO2 in your source water, this will chew through di resin and requires a debasing chamber before the di.

Link that discusses ways to test for CO2. http://spectrapure.com/frequently-asked-questions#calcc02
https://www.aquaticlife.com/blog/how-co2-can-impact-di-resin-consumption/

Are you on city water or a well? I'll have sediment filters turn brown quick different times of the year, they are cheap so I keep a few extra and swap them more frequently than the other filters.

reefertank · May 17, 2018

cmcoker said:
A TDS of 4 shouldn't burn through di resin that quick. Assuming the rain was fresh and properly packed you may be dealing with high CO2 in your source water, this will chew through di resin and requires a debasing chamber before the di.

Link that discusses ways to test for CO2. http://spectrapure.com/frequently-asked-questions#calcc02

Are you on city water or a well? I'll have sediment filters turn brown quick different times of the year, they are cheap so I keep a few extra and swap them more frequently than the other filters.

Going out of the resin it is 10 going out of The Duel ri's it is 4

cmcoker · May 17, 2018

Ok, should be 0 after di, especially with 2 di canisters. Has it ever been 0?

DanielCervantes · May 17, 2018

The di goes after the filters

reefertank · May 17, 2018

No never 0

reefertank · May 17, 2018

I thought the di was last after the resin

reefertank · May 17, 2018

I am thinking maybe my TDS meter is off. I have 2 one is reading 0 and the other 4. I am going to test it at my lfs and see what it reads.

KStatefan · May 17, 2018

DI is the resin

sediment -carbon block-ro membrane-DI resin

Buckeye Hydro · May 22, 2018

Feel free to give us a call when you are in front of the system if you'd like help troubleshooting it.

Some questions we'll ask you:
1. What does your pressure gauge read while the system is running?
2. Are your membranes plumbed in parallel, or in series?
3. What is the TDS of your RO water?

No worries if you're not familiar with the jargon.

Also - from looking at the picture above, you could make an easy low cost improvement to your double DI unit by mounting each DI housing so the ports are on the front/back rather than on the right/left. This would allow you to monitor the TDS coming out of the first DI cartridge. You'll need a few fittings, a little tubing, and 5 minutes to make this happen. We can help if you're interested.

Russ

Bruno516 · May 23, 2018

It should go;
(tap water in) Sediment - Carbon - Membrane - DI - DI (pure water out)

As mentioned above CO2 can eat resin quickly, the Spectrapure test kit is meant for RO water. So I would recommend checking your CO2 in case you haven't. You will essentially test the water coming out of the membrane before it goes into the DI.

As Buckeye mentioned, you should put the DI mountings front to back, you can add a TDS IN/OUT meter to it which will allow you to read the DI water quality. I'd highly recommend going that route to ensure 0 TDS.

reefertank · May 24, 2018

I got it, the problem was definitely pressure, it came with a booster pump that was not raising the pressure at all. I thought the pump was shot. Turns out the resistor was bad. Replaced it and now have 100 psi with booster pump and am turning out 225 gph at 0 ppm.
Thanks everyone for the help.

reefertank · May 24, 2018

Gpd not gph.

Bruno516 · May 24, 2018

reefertank said:
I got it, the problem was definitely pressure, it came with a booster pump that was not raising the pressure at all. I thought the pump was shot. Turns out the resistor was bad. Replaced it and now have 100 psi with booster pump and am turning out 225 gph at 0 ppm.
Thanks everyone for the help.

Good to hear!
I'd still take the recommendation from Buckeye regarding the last DI stages. You will need 4 elbow fittings, 1 dual in-line TDS meter, and some tubing. Here's a diagram. This will allow you to read your DI water quality so you know when to change your DIs.

Hope this helps!