I have been out of the SW game for awhile because of some issues with my last house, when I moved in Dec of '19 I had plans to setup a tank but we all know what happened a few months later just as we were getting settled in... Well the time has come and I have a tank setup and going. I got tired of hauling water 20 miles from the LFS so I went ahead and got a new RO/DI system for this house last week, it was the BRS 4 stage. It has made about 90 gallons of water and the resin is already brown ( really it was where BRS says to replace after less than 60) but the TDS meter still shows 0 and the other filters are still white as they were when I installed them. My question is should I go by the resin color or by the TDS? I have never really trusted the color changing because at my last house it would only be about 50% changed and my TDS meter would be showing 2-3ppm, so I just replaced all the filter every 6-10 weeks because the well I was on was not clean; like the sediment filter would be red within an hour or so of running. any help would be appreciated, I don't mind replacing the resin every couple weeks but that seems a little excessive.
RO/DI resin Color change after ~90 gallons
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Don't rely on color....TDS is the preferred indicator.
What is the source of your raw water....is it well water or city water? Where I live, well water has high CO2 content that depletes the DI real fast.
What is the source of your raw water....is it well water or city water? Where I live, well water has high CO2 content that depletes the DI real fast.
its county water, I am not sure if CO2 is the issue, but I am not sure how it effects DI resin but I have issues with not enough CO2 in my tap water for my planted tanks.
The well water was at the old house, I am on county water now.
sometimes counties have a community well if its rural
Go by tds not the color of the resin. That is the reason I buy non-color changing and save a little money. When I've had color changing it would show it needed changing but I would go another 6 months before I actually got a tds reading above 0.
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The difference is that city supplied well water is handled through a number of filtering steps that de-gasses the CO2. Therefore, I don't believe CO2 is the problem.
I have a dual inline TDS meter that measures pre DI TDS and post DI TDS to give me an idea of filters and DI condition. Suggest getting a TDS readings of raw water, pre DI water to get an idea of ejection rate of your membrane. You should be seeing at least 98 percent ejection.
The other suggestion, especially if you're starting your system frequently, is to install a three way valve pre DI resin so that you can run you RO system with water going to waste for the first 5-10 minutes. The reason is that when you system sits ideal, you get breakthrough of the membrane with TDS. On startup, this high TDS goes through your DI resin, causing it to deplete pretty fast. My breakthrough TDS shoots up to 60-70 TDS on startup. So I flip the valve and run this first couple minutes to waste before making good water.
BRS three way:
Here's the actual valve on my system. The RO water is in the white line coming from the upper left corner. The valve is set to direct RO water through the DI resin (on the right). On startup, the valve is flipped, pointing to the left, directing water to waste.
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I am on a rural water system that is supplied by a series of wells and has high CO2 in it. Prior to adding a degassing chamber I only got about 100 gallons from a mega max cap di resin cartridge
I have a prob pre and post the RO/DI system, It reads 350ish pre and 0 post. The RO is shut off with a float valve, It is running now and has been running for the last few hours so I will let it sit over night, do a water change on one of my FW tanks to use some of the water and see what it shows on start up. Thanks!
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So raw water is 350. I'd suggest putting that probe (assuming in-line) after the membrane, but before the DI. This way you'll be able to see the breakthrough and know when it's good to run water through the DI resin. You should see 7 TDS or lower TDS after a couple minutes.
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Just re-read your post....and here's you problem. Making RO water on demand (using a float valve to shut off the RO) is cause for you system to start and stop multiple times. Each time it sits, breakthough TDS builds up and is flushed through your DI.
I'd only use that float valve to shut the unit off. I'd still manually start the system and, as already mentioned, flush the startup water to waste.
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