Total Dissolved Solids

[damsel-in-distress]

Fellow Reefers,

Just wanted to share some data on water purity in my area. I just got my new TDS meter from Filter Direct Co., in the USA. Here are the readings:

tap water = 60ppm (Holland Road vicinity)

deionized water = 29ppm

bottled distilled water = 0ppm

To interpret the results of the tests, the instructions on the meter say to divide the DI reading by the tapwater reading, substract the result from 1 and multiply by 100 to give you a rejection rate, which in this case works out to be 51.7%. It says the RI resin needs to be replaced if the rejection rate reaches 80% or below.

However, the above calculation is relative. In absolute terms, can any of the gurus out there enlighten me on what is the acceptable amount of total dissolved solids (TDS) that is allowed in a closed aquarium setup and point me in the direction of reliable research?

[damsel-in-distress]

Come on people,

Doesn't anybody have the answer to my question or can advise where I can find the answer?

.. pretty please!

[Infinitereef]

You want your TDS reading to be 0-3. Anything more than 3 is not too good. It may have enough impurities to fuel bad algae. Normally after the tap runs through RO/DI, it should be 0-3, so don't know why you got 29ppm. This is very high consider that your tap water is only 60ppm. Most of the people here will add a 2nd DI chamber to get to 0.

My tap water in US is 230ppm, and yet I can get 0-3ppm after my RO/DI. What RO/DI system did you use? Also, is your TDS meter calibrated?

[Clownfish]

agreed with infinitereef that after RO/DI the results shld be near zero

hav experienced for myself that both will yield 0....

it may be due to ur DI resins being exhausted or u r forcing the water too fast thru the DI

[damsel-in-distress]

You want your TDS reading to be 0-3. Anything more than 3 is not too good. It may have enough impurities to fuel bad algae. Normally after the tap runs through RO/DI, it should be 0-3, so don't know why you got 29ppm. This is very high consider that your tap water is only 60ppm. Most of the people here will add a 2nd DI chamber to get to 0.

My tap water in US is 230ppm, and yet I can get 0-3ppm after my RO/DI. What RO/DI system did you use? Also, is your TDS meter calibrated?

Hi InfiniteReef,

I definitely have had a recent algae bloom after I changed from using NSW to IO synthetic salts. I see the light now!

The water purifier I have is a straight deionizer canister with a disposable resin cartridge, with no RO accompanying units. Its manufactured by Atlas Filtri in Italy. Do you know the brand?

The water quality TDS meter is a part #578 you can get included in a set of RO/DI units that Filter Direct Co., in the USA sells. The manual does not say it requires any caliberation .. actually mentions that any temperature variance ia automatically compensated. Isn't the fact that I did a comparison with distilled water to show zero readings show to some degree it is accurate?

I suspect the DI resin simply requires changing as I bought it secondhand, "only v. slightly used". I will this further but appreciate any further thoughts to my above comments.

Many

[Infinitereef]

Get rid of the straight deionizer canister with a disposable resin cartridge. A DI must always come after the RO. If not, there is too much impurities for the DI to work on and not only you will not get a good water, but also, you have to change the DI resin very frequently which waste a lot of your money.

Get an RO/DI system. Should be much cheaper than you using the DI in long term, because you don't have to change the resin so often.

Your TDS meter should be ok. I got similar TDS meter as well and it should come with calibration already. There should be a calibration report in your box.