TDS meter reading help need please

C

Cloachlover

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Mar 21, 2007
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Hi, im new and hoping you can help me.
i havent set my tank up yet, ive been spending far to much time (months) researching and at the moment im testing all my equipment before i order my live rock for my seahorse tank. it will be SHOWLR 350LTR corner tank.
i have got a new 3 stage ro filter (membrain, sediment and carbon and cocnut hair (?), brand new filters) but no DI filter and no pressure booster pump because i think(?) i have decent level of water pressure going to the ro filter
my tds meter readings are
water coming in 18.1
water coming out 17.2
the ro filter has had about 12 gallons run through it in total at most.
i have let the ro filter run for 10mins before taking this reading (to remove any water left in the ro filter from last use, which should make any old water pass within 10mins?)
i have read that water should be reading 0? so is my out reading at 17.2 really 172ppm? if so something is wrong right?
i brought the TDS meter off ebay second hand, i have not changed the batteries yet.
is my ro machine crap? or is my tds meter wrong? bearing in mind i havent changed the batteries on the TDS meter yet could that cause a false reading?
and at the risk of sounding stupid :confused: i have the in and out connection on the correct pipes, does it matter which way round the in and out fittings are facing on the respective pipe (meaning water in has a red a white cable and water out has white and blue) both wires in and out seem to swivel within the fitting so i dont know if this is relevant?
please help i am new to marine and want to make sure i do this properly for the sake of my fish when i get them.
thanks in advance for any help
 
Without DI resin attaining 0ppm is probably not likely (though it would depend on the TDS of the source water). A membrane should be removing 95-98% of the TDS.

Do you have an inline TDS meter similar to this
http://www.marinedepot.com/ps_ViewI..._Reverse_Osmosis_Purity_Monitors~vendor~.html

If so, where is the IN being read from and where is the OUT being read from?

You wrote "(membrain, sediment and carbon and cocnut hair (?)" but in which order does the water flow through your unit? Not exactly sure what coconut hair is. Can you post a pic of the unit?

I only have experience with a hand held TDS meter and the one in the above link (and they display in whole numbers, so I'm not sure if 17.2 in your case is 17.2ppm or 172ppm).
 
Check if the membrane is in all the way and is sealed. You have a minuscule amount of rejection, about 5%. You should realistically be getting 98%, so effectively zero. Also, you need to let it run longer before taking a reading. I initially let mine run for an hour when new before taking a reading. I know this may be a stupid question or even insulting, but do you have a membrane in the unit (you'd be surprised how often this happens)? Try to write a bit more coherently, please (being honest, not mean). I don't know if it is just me, but I am not understanding some of your other questions toward the end.
 
necigrad said:
I tested the TDS on my water. It was 550/150/0 (approx except the 0, which was dead on) for tap/RO/DI.
Click to expand...

Wow (you must live near the southwest). How often do you go through DI resins? I am lucky in that my water is around 30 or so ppm right out of the tap, 0 out of the membrane, and even more zero out of the two redundant DI canisters.
 
What is the flow of your waste water line vs. your pure water line? It sounds like the RO membbrane isn't installed.
 
It is not coconut hair it's carbonized coconut SHELL.

You should have a SEDIMENT filter then CARBON then RO then DI(if you have DI).

You should have something like 90 to 200 TDS for your tap water (input). You should have something like 50 to 100 TDS out of the CARBON filter. And you should then have between 0 and about 12 or 13 or 14 out of your RO. If you have more than 14 then you need to figure out what's wrong.

After a DI final stage you should have 0 TDS.

You should take your TDS meter to your live fish store and see if they have one that you can compare readings with. Then you will know for sure if yours is okay.
 
Unless there is a ton of chlorine (more than recommended) or a tremendous amount of organic matter in the water, the carbon should not reduce the TDS nearly that much. At best, most people will get a few ppm (usually no more than 10) after carbon cartridges. The only real purpose of carbon in RO/DI units is to keep chlorine from oxidizing the membrane. I do agree that you should double check the meter with another one.
 
hi people

thanks for taking the time to reply

here is a link to a photos of my ro filter

as i brought it
http://i245.photobucket.com/albums/gg41/cloachlover/aed5_1.jpg

then setup

http://i245.photobucket.com/albums/gg41/cloachlover/DSC00430.jpg

info about the 3 stages of filter:
Stage 1 - 5 Micron Sediment Filter: With a five micron rating, it is effective in removing dirt, rust and sand particles. This will catch all the larger particles in order to protect the later filters and membrane.

Stage 2 - Granular Activated Carbon Filter: Reduction of Chlorine, MtBE, Trihalomethanes, Pesticides, Herbicides, Benzene, Radon, and countless Volatile Organic Chemicals. It provides enhanced reduction of taste, odour, and colour.

Stage 3 – 50GPD Reverse Osmosis Membrane A thin film composite (TFC) top quality membrane that processes up to 190 ltrs of pure water per day. It removes the following hard water contaminants that may be present in your water: lead, cooper, barium, chromium, mercury, sodium, cadmium, fluoride, nitrite, nitrate, and selenium.

my tds meter is the same as the one as the one in the link a few posts above.

im sorry if i didnt explain myself very well, With regards to the in/out sensor wires swivling, I will try again.....

if you look at the pic which shows the filter set up, just below the TDS IN sensor connection there is red tape (rubber?) which connects to the red/white wires then to TDS meter, and just below the OUT sensor there is blue tape which connects to the blue/white wires then to the TDS meter.

well these taped parts can swivel 360 deg within the sensor connections, (which mean if twisted enough can cause the wires to twist) again i dont know if its relivent, just try to provide as much info as poss

im not sure of the water quilty in my area, but i do know its very soft, i guess il have to do a bit of research.

im sure i have set the filter up properly but am starting to worry ive done something wrong, the instructions werent the greatest to say the least.

i think i should do as reckomended and go and see my guy at the lfs and compare readings?

i dont really know what else to do other than that, i just hope its a dodgy TDS Meter and not a dodgy RO Filter i have.

again thanks for your time and sorry for the long post
 
sorry forgot to add the IN connector is 5" before the first stage sediment cartridge and the OUT connector is 8" after the 3rd stage tfc filter.
 
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