RO/DI when to take action

fatdaddy · 06/05/2007, 09:06 AM

My TDS went from 0 to 6. My input is 486. When do you take action to renew DI crystals or RO membrane. They crystals haven't changed color.

Shooter7 · 06/05/2007, 09:16 AM

I keep my RO/DI TDS at 0 - 1. Once it starts getting to 2 - 3, I change the DI resin.

kuoka · 06/05/2007, 10:18 AM

'They' say to change the filters every 6 mos or so and the RO filter every two years. I change my filters every 6 mos and we have decent water quality.

WaterKeeper · 06/05/2007, 10:42 AM

We're talking here about exhaustion of the DI resin in this case. Once the TDS starts to increase it will usually rise fairly rapidly to the TDS of the RO units output. It is then time to replace the DI canister. If it is not replaced it may even experience "breakthrough" where the DI output is worse than the RO's output.

The RO stage should last for several years. Prefilters usually indicate they have reached their limits when output of the unit starts to fall off. This depends on the quantity of particulate matter in the source water so if differs for every unit.

drummereef · 06/05/2007, 12:01 PM

I agree with Shooter and Waterkeeper. I change out my DI resin once it is above 1 tds.

AZDesertRat · 06/05/2007, 05:02 PM

Color changing DI resin is a horrible indicator of resin condition, its very unpredictable on how it will turn if at all. A TDS meter is your best friend.
Prefilters and carbons should be changed every 6 months, RO membranes should last 3-5 years if you keep up with the filter replacements and disinfection procedure and DI is entirely dependent on how well your membrane is working and how much water you make. A good RO by itself should be 95-98% efficient and DI is the final polishing filter. If the RO is working good DI can last months and months, if its not it can be exhausted in a day or two.
Prefilters and carbons have little to no effect on final TDS so it comes down the the membrane and the DI. Once DI is exhausted it begins to release what it has accumulated and can often release it in higher levels than what was in the tap water to begin with so don't wait too long. Things that get released first are weakly ionized substances like silicates and phosphates and you don't want either of those in your reef.

virginiadiver69 · 06/05/2007, 05:31 PM

AZDesertRat, what gets disinfected? I change my prefilters when needed but have never heard of anything needing to be disinfected. What other regular maintenance does an ro/di unit need?

AZDesertRat · 06/05/2007, 05:55 PM

All housings should be disinfected at least annually. I do it every 6 months when I change filters since it only takes a few minutes. Most vendors should have a hand out or procedure on their sites. All it takes is about 3 spoons full of regular unscented bleach and a few minutes while the filters are removed. Disconnect the line from the last carbon up to the RO membrane, put a few spoons of bleach in the first housing, screw the empty housings back on, turn the water back on and let the bleach circulate through the housings for a bit. Empty them out, install the new cartridges, open the water and bleed the air out the disconnected tube, reconnect it and you are in business. This helps to prevent and bacteria or virus growth inside the housings. This is especially important if you use the unit for drinking water and pet watering as I do or if it is exposed to heat or sunlight.

fatdaddy · 06/05/2007, 07:19 PM

Another question: My water source is municipal well water, so I'd bet me 486 input reading is more like 1486. With the drought our usual 1000 TDS has gone steadily higher. I'm thinking of continuing to use my Water General RO/DI unit for drinking water, etc. And, then daisy chain a second Kent Hi-S RO/DI unit for aquarium water. Does this seem reasonable?

I've had persistent problems with diatoms although a silicates test keeps showing zero. It has me perplexed.

06/05/2007, 09:06 AM	#1
fatdaddy Registered Member Join Date: Apr 2007 Location: Northeast Florida Posts: 1,191	RO/DI when to take action My TDS went from 0 to 6. My input is 486. When do you take action to renew DI crystals or RO membrane. They crystals haven't changed color. __________________ "We are what we repeatedly do. Excellence, then, is not an act, but a habit." -- Aristotle

06/05/2007, 09:16 AM	#2
Shooter7 Registered Member Join Date: Nov 2004 Location: Tolono, IL Posts: 6,754	I keep my RO/DI TDS at 0 - 1. Once it starts getting to 2 - 3, I change the DI resin. __________________ Dave Current Tank Info: 10 years salty - standard 29g reef - moved from 120 gal reef, 2x250w Reeflux 10k's on ARO electronics and VHO super actinics on Icecap ballast, 2xTunze 6060, MSX 200 skimmer, GEO 612 Ca reactor, mag 12 return

06/05/2007, 10:18 AM	#3
kuoka Premium Member Join Date: Mar 2005 Location: NorCal Cali Posts: 713	'They' say to change the filters every 6 mos or so and the RO filter every two years. I change my filters every 6 mos and we have decent water quality. __________________ They say don't talk about someone unless you've walked a mile in their shoes.. But if you do, at least you'll be ahead of them AND have their shoes! :) Current Tank Info: 72gal glass bow front reef, mostly LPS with some SPS, tangs, anthias, blenny, paired percula clowns, gold headed sleeper goby, red fairy wrasse

06/05/2007, 10:42 AM	#4
WaterKeeper Bogus Information Expert Join Date: Oct 2000 Location: SW Ohio Posts: 16,147	We're talking here about exhaustion of the DI resin in this case. Once the TDS starts to increase it will usually rise fairly rapidly to the TDS of the RO units output. It is then time to replace the DI canister. If it is not replaced it may even experience "breakthrough" where the DI output is worse than the RO's output. The RO stage should last for several years. Prefilters usually indicate they have reached their limits when output of the unit starts to fall off. This depends on the quantity of particulate matter in the source water so if differs for every unit. __________________ "Leading the information hungry reefer down the road to starvation" Tom Current Tank Info: 130 Now out of service and a 29

06/05/2007, 12:01 PM	#5
drummereef Team RC Member Join Date: Jul 2006 Location: STL Posts: 14,754	I agree with Shooter and Waterkeeper. I change out my DI resin once it is above 1 tds. __________________ -Brett 180g Marineland Starfire In-Wall 278 gallon system

06/05/2007, 05:02 PM	#6
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Color changing DI resin is a horrible indicator of resin condition, its very unpredictable on how it will turn if at all. A TDS meter is your best friend. Prefilters and carbons should be changed every 6 months, RO membranes should last 3-5 years if you keep up with the filter replacements and disinfection procedure and DI is entirely dependent on how well your membrane is working and how much water you make. A good RO by itself should be 95-98% efficient and DI is the final polishing filter. If the RO is working good DI can last months and months, if its not it can be exhausted in a day or two. Prefilters and carbons have little to no effect on final TDS so it comes down the the membrane and the DI. Once DI is exhausted it begins to release what it has accumulated and can often release it in higher levels than what was in the tap water to begin with so don't wait too long. Things that get released first are weakly ionized substances like silicates and phosphates and you don't want either of those in your reef.

06/05/2007, 05:31 PM	#7
virginiadiver69 Registered Member Join Date: Dec 2006 Location: Va. Posts: 4,400	AZDesertRat, what gets disinfected? I change my prefilters when needed but have never heard of anything needing to be disinfected. What other regular maintenance does an ro/di unit need? __________________ Semi-aggressive mixed reef w/ shallow sand bed 96x30x27 310gal custom acrylic w/ ext. "fail safe" overflow 125gal sump/cryptic fuge w/ 6" DSB 3 400w Plus Rite 20k MH in Lumembrights 2 250w Plus Rite 20k MH in spider reflectors VHO actinic supplementation 2 Tunze wave boxes 2 Tunze 6060 in Tunze Rocks 2 Tunze 6125 Reeflo 250 skimmer Hammerhead return on OM 4 way Aqua controller lll Leviton power panel Deltec Eco-Cooler Randy's Two part 6.5 kw generator

06/05/2007, 05:55 PM	#8
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	All housings should be disinfected at least annually. I do it every 6 months when I change filters since it only takes a few minutes. Most vendors should have a hand out or procedure on their sites. All it takes is about 3 spoons full of regular unscented bleach and a few minutes while the filters are removed. Disconnect the line from the last carbon up to the RO membrane, put a few spoons of bleach in the first housing, screw the empty housings back on, turn the water back on and let the bleach circulate through the housings for a bit. Empty them out, install the new cartridges, open the water and bleed the air out the disconnected tube, reconnect it and you are in business. This helps to prevent and bacteria or virus growth inside the housings. This is especially important if you use the unit for drinking water and pet watering as I do or if it is exposed to heat or sunlight.

06/05/2007, 07:19 PM	#9
fatdaddy Registered Member Join Date: Apr 2007 Location: Northeast Florida Posts: 1,191	Another question: My water source is municipal well water, so I'd bet me 486 input reading is more like 1486. With the drought our usual 1000 TDS has gone steadily higher. I'm thinking of continuing to use my Water General RO/DI unit for drinking water, etc. And, then daisy chain a second Kent Hi-S RO/DI unit for aquarium water. Does this seem reasonable? I've had persistent problems with diatoms although a silicates test keeps showing zero. It has me perplexed. __________________ "We are what we repeatedly do. Excellence, then, is not an act, but a habit." -- Aristotle