When to change DI resin?
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redfishbluefish
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Don't rely on color.....use a TDS meter to determine when your resin is shot. When you're getting TDS greater than 0, it's time to change the DI Resin.
ngvu1
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I never heard lof them lol. I started out with a tds meter and never have used anything else . I did use the hydrometer when first started out ... those days lol
I never heard lof them lol. I started out with a tds meter and never have used anything else . I did use the hydrometer when first started out ... those days lol
Get yourself a good $25-$30 ATC handheld TDS meter like the HM Digital TDS-3, TDS-4TM or AP-1. Never rely on color changing resins, most are very inaccurate and you are passing weakly ionized substances like phosphates, silicates and nitrates way before it turns color.
nervousmonkey
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+1 to this for sure!!!
Salty1962
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It's good to have a flush valve on your rodi so you can flush out your membrane and run your water until you get @2-3 tds. BRS sales some good kits for this. Goes a LONG way in extending the life of your DI.
I have one and I'm still on my first batch of DI after several months. Pays for itself in the long run.
I have one and I'm still on my first batch of DI after several months. Pays for itself in the long run.
Flush kits are a waste of money. They are on the waste side and do nothing for your DI which is on the treated side.
A DI bypass valve does help your DI though. It is simply a tee between the RO and the DI with a ball valve on it that you open when you first start the system and flush the first few ounces of RO water out which contains TDS creep.
A DI bypass valve does help your DI though. It is simply a tee between the RO and the DI with a ball valve on it that you open when you first start the system and flush the first few ounces of RO water out which contains TDS creep.
akaemu
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shortly after the resin turns brown ( all brown ) tds will creep here perhaps it does change colors for a reason?
If it's not all brown continue normal busissness or add a second stage then alternate the depleted with the full cartridge so you always have a full
I can tell you here on a well tds will creep when my cartridge is all brown after about 10 gallons of ro after the cartridge is total brown.
If it's not all brown continue normal busissness or add a second stage then alternate the depleted with the full cartridge so you always have a full
I can tell you here on a well tds will creep when my cartridge is all brown after about 10 gallons of ro after the cartridge is total brown.
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Again don't depend on color change. Weakly ionized contaminants do not register well on a hobbyist grade TDS meter and you will be passing things you don't even realize even before it changes color. Always depend on a good handheld ATC TDS meter and change it immediately when you see anything other than 0 TDS after a minute or so of running.
Salty1962
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Maybe I got it incorrect but in my case it has helped extend the life of my resin. No valve is going to bypass the TDS that goes into your filters but if I don't put water through my DI that has a higher TDS then it will extend the life of the DI. Whatever it flushes out, creep, it does help. I have used one for years and do believe in them but that is just me.
If it is a "flush kit" it is installed on the waste line and bypasses the flow restrictor to flush out accumulated TDS on the waste side of the RO membrane. If it is a DI bypass valve it is installed on the treated water side of the RO membrane before the water enters the DI resin.
TDS creep is present in all membrane systems. When you shut the system off after making water, the treated water inside the membrane is agressively trying to get back to its natural "dirty" state so it actually pulls TDS out of the tap water on the waste side of the membrane until the TDS equalizes on both sides, this is referred to as TDS creep.
No amount of flushing with a flush kit is going to reduce this TDS creep since it is already on the treated side of the membrane but a DI bypass valve which you open up on start up does reduce this creep back to your normal +/-2% of the incoming tap water TDSin just a minute or so when you can then shut the bypass and make RO/DI water.
Two very different things placed at two very different spots in the treatment process and used for different purposes. One is more a warm and fuzzy feeling, the other has proven benefits.
TDS creep is present in all membrane systems. When you shut the system off after making water, the treated water inside the membrane is agressively trying to get back to its natural "dirty" state so it actually pulls TDS out of the tap water on the waste side of the membrane until the TDS equalizes on both sides, this is referred to as TDS creep.
No amount of flushing with a flush kit is going to reduce this TDS creep since it is already on the treated side of the membrane but a DI bypass valve which you open up on start up does reduce this creep back to your normal +/-2% of the incoming tap water TDSin just a minute or so when you can then shut the bypass and make RO/DI water.
Two very different things placed at two very different spots in the treatment process and used for different purposes. One is more a warm and fuzzy feeling, the other has proven benefits.
Just for giggles test the TDS before and after then report back. I think you may be disappointed. In theory they sound great.
I am saying vendors make a few $$ profit on them and it makes the end user feel like he is doing something good. I have not seen one single documented report from a third party test lab showing they do anything at all. Large scale commercial and municipal membrane systems flush but it is very different, they inject chemicals to clean the membrane and they have large pumps that produce several times the rated capacity of the membranes that actually provide enough volume and capacity to actually scour the membranes. A little 1/4" ball valve at house pressure and without chemical cleaning just doesn't do anything other than make you happy and lighten your wallet.
Use your handheld TDS meter to determine how long you should leave the DI bypass valve open on start up. Once the RO only TDS drops to its normal TDS any further flusing isn't needed as the TDS creep is gone. Doesn't take long if you have fairly low tap TDS and softened water.
joshkirkland83
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So on any rodi system with a flush kit, you can just disconnect the line into the di when flushing if you don't have a vavle? And you're good right?
