What is an acceptable TDS reading?

[cital]

I have a 4 stage ro/di unit that has been running for 6 months or so, I just took a TDS reading for the first time and it read 002 is this ok or should I change the filters? The tap water at my house read 345 I think. Just not sure what an acceptable range is, thanks for any feedback!

[CIGDAZE]

2 would be a very good reading coming out of your RO going into your DI.
But the DI product water should read zero. When I see my TDS go from zero to 1 I change my DI media.
Generally speaking, this is about every 6 months for me.

[patsfan1130]

Mine get changed as soon as it yields anything higher than zero. Is 002 acceptable? For some yes. You will get many different answers on this. My thoughts are....We buy RO/DI units to produce 0 TDS for us...Anything higher is not acceptable.

[cital]

BTW I have a FOWLR tank, no corals, inverts. Not sure if that is a big factor.

[James404]

I agree you buy ro/di units so you can get 0 TDS, when you start getting higher its time to change filters/DI. Can you use it with 002 tds for the time being? Yes but I wouldnt for long...

[GhostCon1]

zero!!!!!!!

[r-balljunkie]

Meh,

every one shoots for the holy grail # of zero. i think its a bit picky and OCD. personally, any value under 15 ppm is more than adequate for your system, FO or hardcore SPS. i have never had any hair algae issues in all my years of reefing.

[Floowid]

I don't even run the DI part. My TDS is usually around 10 out of the RO unit. I have been doing it this way since before DI became popular. I have no problems.

[TellyFish]

0 is the best. Anything else is "acceptable", up to some limit you will have to set for yourself.

Personally, I don't like to see more than 10 out of my RO/DI--or at least that is the point when my laziness is overcome by fear, to the point that I can muster enough energy to wheel myself over to the computer and order a new set of filters from the internet.

[outy]

Meh,

every one shoots for the holy grail # of zero. i think its a bit picky and OCD. personally, any value under 15 ppm is more than adequate for your system, FO or hardcore SPS. i have never had any hair algae issues in all my years of reefing.

its hard to say whats acceptable for some ones water you havnt tested and after 14 years of reefing I know your statement is flat false

15ppm is something I would never use as my silicate level is high and that would garantee diatoms in my tank and my TDS out of the tap is only 27-32ppm

you also have seasonal water changes that could make 15TDS very very bad water as to where some can get away with 15tds with no issues

the fact OP runs a FOWLR I think 002 might not have a bad effect but being safe is much better then sorry

everyones water is different so there is no blanket statement like xxx amount of TDS is acceptable. only OP can answer this

[Jstdv8]

I'm having trouble ponying up the cash for a new set of filters and my TDS coming out my RO/DI right now is 62.
I have cyano like a mo-fo, but other than that I don't notice any difference.

[Nwest]

My question i have is i just installed my new ro/di unit and we calibrated it at the store to zero. My water coming out of ro is 6ppm befor going into di part. Is this ok or should it be lower?

[Sisterlimonpot]

its hard to say whats acceptable for some ones water you havnt tested and after 14 years of reefing I know your statement is flat false

15ppm is something I would never use as my silicate level is high and that would garantee diatoms in my tank and my TDS out of the tap is only 27-32ppm

you also have seasonal water changes that could make 15TDS very very bad water as to where some can get away with 15tds with no issues

the fact OP runs a FOWLR I think 002 might not have a bad effect but being safe is much better then sorry

everyones water is different so there is no blanket statement like xxx amount of TDS is acceptable. only OP can answer this
You’re right, you never know what that 15 PPM is unless you pay to have it tested. More times then not, it’s going to be something that isn’t good for the tank. Unless it’s that rare occasion that it is something good like calcium. You want to shoot for 0 PPM.

OP if it is 2 PPM, all you need to do is replace the DI resin and the numbers will go back to 0. For it being a fish only tank 2ppm is not a big deal. It’s not going to harm your livestock at all, the only concern is that it may promote algae growth. But for a FOWLR I would be too concerned.

[Sisterlimonpot]

My question i have is i just installed my new ro/di unit and we calibrated it at the store to zero. My water coming out of ro is 6ppm befor going into di part. Is this ok or should it be lower?

6PPM is fine, I would suggest monitoring it for a few minutes after first turning on, the TDS (out of the RO) will slightly rise and then drop down to below 6ppm (1-2ppm). Many guys bypass the DI for the first few minutes to save the life of the DI. (it should go without saying, not to put that water in the tank but don't waste it either)

what's coming out of your tap?

[Nwest]

not sure whats coming out of my tap my meter only reads what comes in di and what comes out of di

[TellyFish]

For the record, my water comes from Lake Michigan and is around 140tds from the tap. If you have SPS or other sensitive animals, its good practice to shoot for 0tds in an effort to rule out anything nasty.

My tank is unhappy when I am lazy.

[Flame_Angel]

My tank is unhappy when I am lazy.
And just like a wife, if your tank ain't happy, you ain't happy.

[thegrun]

I start to think about changing mine out around 3, but it usually up to 4 by the time I get around to it!

[TellyFish]

I start to think about changing mine out around 3, but it usually up to 4 by the time I get around to it!

That's me every-time, lol! If I would just learn my lesson, I would buy 2 sets of filters next time... :crazy1:

[manix man]

There is another can of worms here a TDS can't actually test all impurities. It's about the positive and negative ions springs to mind. So zero isn't actually necessarily zero in practice.

Most important thing is keep on top of the carbon filter, that is what keeps the membrane working.

[outy]

There is another can of worms here a TDS can't actually test all impurities. It's about the positive and negative ions springs to mind. So zero isn't actually necessarily zero in practice.

Most important thing is keep on top of the carbon filter, that is what keeps the membrane working.

not really carbon does nothing with solids in the water, it removes chemicals but does very little to stop the solids that the membrane takes out. I would have to say the micron filter built in and the prefilter do a better job at making the membrane last longer. its a good thing the holes are so small in the membrane that there on the molecular level lol if the carbon doesnt take out most chemicals they get thrown out in the waist water

i can always let my carbon elements stay in for years and still get 0 TDS

when the DI resin goes south I get diatoms so thats a easy fix :)

true 0 isnt 0 but thats why we have DI resin, a good functioning ro/do unit should make labratory grade water

[R33f3r]

I have 10 ppm and it's fine. No hair algae or anything.

[Sisterlimonpot]

not really carbon does nothing with solids in the water, it removes chemicals but does very little to stop the solids that the membrane takes out. I would have to say the micron filter built in and the prefilter do a better job at making the membrane last longer. its a good thing the holes are so small in the membrane that there on the molecular level lol if the carbon doesnt take out most chemicals they get thrown out in the waist water

i can always let my carbon elements stay in for years and still get 0 TDS

when the DI resin goes south I get diatoms so thats a easy fix

true 0 isnt 0 but thats why we have DI resin, a good functioning ro/do unit should make labratory grade water
The carbon is essential to the RO membrane working properly because if it is spent you will allow chlorine to pass through and chlorine will ruin the membrane fairly quickly. Unless you're pulling your water from a well (or anything other than a municipal water supply that adds chlorine) you'll want to change your carbon filter regularly.

[Sisterlimonpot]

I have 10 ppm and it's fine. No hair algae or anything.
as already stated, that 10 PPM may be something that is beneficial to the aquarium. Not everyone is going to get the same results you do with 10 PPM.

[cloak]

TDS, what's that? I've been using tap water for almost 14 years now without any problems. It makes me wonder sometimes when I see multiple threads like this where people are using RO/DI and still can't get it right. Maybe YOUR just not cut out for this stuff. Chasing numbers can be a bad thing sometimes.

BTW, luck was thrown out the window a long time ago...

FWIW.

[Sisterlimonpot]

You're in Stockton and have no problems? do you dose carbon or something that removes N and P? have you ever had the water tested to what the TDS consists of?

[cloak]

No, no, & no.

FWIW were the operative words.

;)

[outy]

The carbon is essential to the RO membrane working properly because if it is spent you will allow chlorine to pass through and chlorine will ruin the membrane fairly quickly. Unless you're pulling your water from a well (or anything other than a municipal water supply that adds chlorine) you'll want to change your carbon filter regularly.

i just based my findings on not changing carbon elements for close to 4 years and held 0 tds out of my membrane.

Possibly I dont have that much chlorine in my water that and my ppm is realy low for tap [despite the low numbers summer months bring in huge amounts of silicates