What is an acceptable PPM TDS reading for RODI water?

SPSFiend · 10/29/2007, 09:49 AM

I am wondering what is an acceptable TDS PPM reading for RODI water to be used for top off?

I live in Los Angeles and got a 325 reading on my RODI water! So I took another measurement off off new RODI water in a different container and got 25.

I checked out my 38G rubbermaid and noticed some slimy stuff at the bottom. Those of you that have RODI tanks, do you clean them out from time to time? I keep it covered but I did not have a pump in it for circulation.

What do I need to do differently to the container to prevent the water from spoiling?

sasscuba · 10/29/2007, 09:54 AM

Wow 325? I never put anything higher than 6 in mine and I get it from the grocery store RO machine.

SPSFiend · 10/29/2007, 11:35 AM

Man, I just replaced my sediment cartridge... Is LA tap water that bad?
I guess I will try replacing and seeing if I see an improvement.

Kenfuzed · 10/29/2007, 11:50 AM

If you have something slimy in the bottom of your container then something contaminated it. Is the 25 reading from the container or from the RO/DI effluent? I don't think you should be getting any higher than 001 or 002 from your final DI cartridge, and less than 005 or 006 from your RO membrane if its not too old. I get 002 from the RO and 0-001 from my DI. Normally I only make up enough to last a week or two and wahs out my storage container with RO water on a regular basis. I also keep it sealed.

I recall reading that since RO/DI water doesn't have any chlorine or buffers it is prone to bacterial growth if left in an open air container too long.

SPSFiend · 10/29/2007, 11:54 AM

25 was straight from the system. Is it possible that the my TDS is not reading correctly or are those units pretty robust?

roxy25 · 10/29/2007, 12:30 PM

Well Since I have a nano I use a 18 gallon rubbermaid tube. I usually only make what I need. I make at least 10 gallons a week for my ATO/WC. I clean it ( or just wipe it out with a paper towel) I let my water sit one time because I made extra water and I did a reading it was 245ppm ? so I never let it sit like that again not sure why. I was thinking maybe some residue from my new SW was left in there. ( I use the same tub to mix my SW).

My TDS meter reads 000ppm I was at 15 last week and I replaces the media because it was brown. And the first stage filter was used up. A few people told me 20 is the highest you should let it get.

whatta · 10/29/2007, 12:51 PM

325 is about right because one of my professors actually works for LADWP and he's told us that 350 is the average level of TDS. And I believe I remember him telling the class that 450 or 400 is the highest that it could go up to before they have to filter it out.

Bebo77 · 10/29/2007, 12:58 PM

my tap water from LA DWP is between 275 and 300...

i will let my rodi get up to 50 before i replace filters...

Freed · 10/29/2007, 01:06 PM

My tap water is 155 and the output effluent is 0. I would have to say one of your filters(sediment or carbon block) need to be replaced or recharged(DI).

Kenfuzed · 10/29/2007, 01:56 PM

My tap has a reading of ~245 but if my RO/DI ever had a reading that high (stored or not) I'd toss it and start looking into what contaminated it.

SPSFiend · 10/29/2007, 02:00 PM

Thanks everyone! With your tips I will be able to pinpoint the source.

I also will clean out my RODI container periodically instead of pretty much keeping it full. I let it get low but there is usually a few inches always left on the bottom... I did not realize that bad bacteria would grow in it...

I used to mix in kalwasser and had a pump in it but it was clogging up all my lines so I stopped and I took out the pump.

Kenfuzed · 10/29/2007, 02:14 PM

If you used to mix kalk in the same container that could account for some of it. The residual kalk would leach back into the water and elevate the TDS count.

Another thing to watch for is pets or pests. If you have a dog lapping up water it could be leaving some backwash. Also if your vat is outdoors things like insects or even field mice could be taking a dip. Always keep your water covered.

Another thing to watch is your DI resin. Once it is exhausted it will start leaching back everything it ever captured and could actually make your water worse. checking each stage (RO and DI) will determine if one or the other is bad.

lowbudget · 10/29/2007, 04:36 PM

i live in the same area. i have a di filter too. i dont let any water higher then 5 in my tank. you might want to wash out the slime stuff.

bromion · 10/29/2007, 08:04 PM

I have a 55 gallon RO/DI storage container. It's one of the food-grade barrels. It does not seem to get any slime on it. I keep it covered, so it's dark, which probably helps.

You should check the TDS output of your RO membrane. If that is above around 10ppm, there is a problem. Check the chlorine levels going into the membrane. They should be undetectable. I made the mistake once of buying sediment filters that did not remove chlorine and it shot my membrane. Costly mistake.

dchan928 · 10/29/2007, 10:23 PM

I was watching the news today and they said fluoride would be added to tap water soon....will that affect the TDS readings or water quality?

Roscovitch · 12/03/2017, 10:18 AM

I know this is an old thread but just in case anybody is interested. I live in Scotland and the water TDS from the tap is around 25 and I've been using that and growing corals for over 30 years.

lowbudget · 12/03/2017, 04:07 PM

And I’m sure you can. At 25

10/29/2007, 09:49 AM	#1
SPSFiend Registered Member Join Date: Nov 2005 Location: South Bay / Los Angeles Posts: 1,018	What is an acceptable PPM TDS reading for RODI water? I am wondering what is an acceptable TDS PPM reading for RODI water to be used for top off? I live in Los Angeles and got a 325 reading on my RODI water! So I took another measurement off off new RODI water in a different container and got 25. I checked out my 38G rubbermaid and noticed some slimy stuff at the bottom. Those of you that have RODI tanks, do you clean them out from time to time? I keep it covered but I did not have a pump in it for circulation. What do I need to do differently to the container to prevent the water from spoiling? __________________ Thanks, Gerry Current Tank Info: Custom 32x32x24 Rimless. Previous tanks: 180G Reef and 120G Reef

10/29/2007, 11:35 AM	#3
SPSFiend Registered Member Join Date: Nov 2005 Location: South Bay / Los Angeles Posts: 1,018	Man, I just replaced my sediment cartridge... Is LA tap water that bad? I guess I will try replacing and seeing if I see an improvement. __________________ Thanks, Gerry Current Tank Info: Custom 32x32x24 Rimless. Previous tanks: 180G Reef and 120G Reef

10/29/2007, 11:50 AM	#4
Kenfuzed Registered Member Join Date: Apr 2002 Location: Riverview FL Posts: 2,557	If you have something slimy in the bottom of your container then something contaminated it. Is the 25 reading from the container or from the RO/DI effluent? I don't think you should be getting any higher than 001 or 002 from your final DI cartridge, and less than 005 or 006 from your RO membrane if its not too old. I get 002 from the RO and 0-001 from my DI. Normally I only make up enough to last a week or two and wahs out my storage container with RO water on a regular basis. I also keep it sealed. I recall reading that since RO/DI water doesn't have any chlorine or buffers it is prone to bacterial growth if left in an open air container too long. __________________ ============================================= In between tanks. Current Tank Info: Recently moved, will have a new tank up soon.

10/29/2007, 11:54 AM	#5
SPSFiend Registered Member Join Date: Nov 2005 Location: South Bay / Los Angeles Posts: 1,018	25 was straight from the system. Is it possible that the my TDS is not reading correctly or are those units pretty robust? __________________ Thanks, Gerry Current Tank Info: Custom 32x32x24 Rimless. Previous tanks: 180G Reef and 120G Reef

10/29/2007, 12:30 PM	#6
roxy25 Registered Member Join Date: Feb 2004 Location: Eastvale, California Posts: 3,118	Well Since I have a nano I use a 18 gallon rubbermaid tube. I usually only make what I need. I make at least 10 gallons a week for my ATO/WC. I clean it ( or just wipe it out with a paper towel) I let my water sit one time because I made extra water and I did a reading it was 245ppm ? so I never let it sit like that again not sure why. I was thinking maybe some residue from my new SW was left in there. ( I use the same tub to mix my SW). My TDS meter reads 000ppm I was at 15 last week and I replaces the media because it was brown. And the first stage filter was used up. A few people told me 20 is the highest you should let it get. __________________ Kerry Kerry, Ireland Kerry Blue Terrier Kerry Hill Current Tank Info: Shallow zoa tank

10/29/2007, 09:54 AM	#2
sasscuba Registered Member Join Date: Oct 2006 Location: Owasso, Oklahoma Posts: 990	Wow 325? I never put anything higher than 6 in mine and I get it from the grocery store RO machine.

10/29/2007, 12:51 PM	#7
whatta Registered Member Join Date: Aug 2007 Location: Orange Posts: 157	325 is about right because one of my professors actually works for LADWP and he's told us that 350 is the average level of TDS. And I believe I remember him telling the class that 450 or 400 is the highest that it could go up to before they have to filter it out.

10/29/2007, 12:58 PM	#8
Bebo77 Premium Nonpaying Member Join Date: Jul 2005 Location: Lost Posts: 14,377	my tap water from LA DWP is between 275 and 300... i will let my rodi get up to 50 before i replace filters... __________________ Gabriel Current Tank Info: 300 Gal Envision Tank(98Lx30Wx26T) 120 Gal SoCalCreations Sump, Deltec TC2560, 2 LumenarcsMini 1 Reg on a light mover W Radiums 250& 400, Gallaxy ballasts, Red Dragon 10m3 return W/ 2 WavySeas, 2 6155 Tunze streams

10/29/2007, 01:06 PM	#9
Freed It's what it's Join Date: Mar 2003 Location: 41° 2' 45" N 85° 8' 43" W Posts: 7,579	My tap water is 155 and the output effluent is 0. I would have to say one of your filters(sediment or carbon block) need to be replaced or recharged(DI). __________________ Freed Current Tank Info: 180gal(1120 watts of MH/VHO light), 60gal "sump", Deltec 601 calcium reactor, Euro Reef CS8-3+ skimmer, 20 gallon QT

10/29/2007, 01:56 PM	#10
Kenfuzed Registered Member Join Date: Apr 2002 Location: Riverview FL Posts: 2,557	My tap has a reading of ~245 but if my RO/DI ever had a reading that high (stored or not) I'd toss it and start looking into what contaminated it. __________________ ============================================= In between tanks. Current Tank Info: Recently moved, will have a new tank up soon.

10/29/2007, 02:00 PM	#11
SPSFiend Registered Member Join Date: Nov 2005 Location: South Bay / Los Angeles Posts: 1,018	Thanks everyone! With your tips I will be able to pinpoint the source. I also will clean out my RODI container periodically instead of pretty much keeping it full. I let it get low but there is usually a few inches always left on the bottom... I did not realize that bad bacteria would grow in it... I used to mix in kalwasser and had a pump in it but it was clogging up all my lines so I stopped and I took out the pump. __________________ Thanks, Gerry Current Tank Info: Custom 32x32x24 Rimless. Previous tanks: 180G Reef and 120G Reef

10/29/2007, 02:14 PM	#12
Kenfuzed Registered Member Join Date: Apr 2002 Location: Riverview FL Posts: 2,557	If you used to mix kalk in the same container that could account for some of it. The residual kalk would leach back into the water and elevate the TDS count. Another thing to watch for is pets or pests. If you have a dog lapping up water it could be leaving some backwash. Also if your vat is outdoors things like insects or even field mice could be taking a dip. Always keep your water covered. Another thing to watch is your DI resin. Once it is exhausted it will start leaching back everything it ever captured and could actually make your water worse. checking each stage (RO and DI) will determine if one or the other is bad. __________________ ============================================= In between tanks. Current Tank Info: Recently moved, will have a new tank up soon.

10/29/2007, 04:36 PM	#13
lowbudget Registered Member Join Date: Oct 2006 Location: Los Angeles Posts: 5,258	i live in the same area. i have a di filter too. i dont let any water higher then 5 in my tank. you might want to wash out the slime stuff.

10/29/2007, 08:04 PM	#14
bromion Registered Member Join Date: Oct 2005 Location: Pasadena, CA Posts: 2,576	I have a 55 gallon RO/DI storage container. It's one of the food-grade barrels. It does not seem to get any slime on it. I keep it covered, so it's dark, which probably helps. You should check the TDS output of your RO membrane. If that is above around 10ppm, there is a problem. Check the chlorine levels going into the membrane. They should be undetectable. I made the mistake once of buying sediment filters that did not remove chlorine and it shot my membrane. Costly mistake.

10/29/2007, 10:23 PM	#15
dchan928 Registered Member Join Date: Aug 2006 Location: Irvine, CA Posts: 158	I was watching the news today and they said fluoride would be added to tap water soon....will that affect the TDS readings or water quality? __________________ David

12/03/2017, 10:18 AM	#16
Roscovitch Registered Member Join Date: Nov 2017 Posts: 19	RO Readings. I know this is an old thread but just in case anybody is interested. I live in Scotland and the water TDS from the tap is around 25 and I've been using that and growing corals for over 30 years.

12/03/2017, 04:07 PM	#17
lowbudget Registered Member Join Date: Oct 2006 Location: Los Angeles Posts: 5,258	And I’m sure you can. At 25