Ro/di And Tds

[saltwaterdave]

I do not have a ro/di unit yet.I brought a handheld tds meter off of e-bay and it measured my tds at 61 for the water I have been using for my top-off,it measured water straight from the tap at 143.I have a friend that has a tds meter plugged into his auotmated top off system,his does not give numbers just a red and a green light,we check the same with with his and the light turned green,checked mt tap water and the light turned red.How much faith can I put into this tds meter,I know 61 is high and now I am worried.I hav'nt checked any other water yet like the bottled water you get from wally world.Can I add something to the water to help it for the time being??? This what I got from e-bay:
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=2944062086
Thanks,
David
I also add lime to my top-off water,does that make a difference?

[AZDesertRat]

You can buy calibration standards for TDS meters that are pretty cheap. How are you getting your top off water down to 61 from 143? You are actually lucky, here in Phoenix our tap water is around 450! I have a 75 GPD RO with a 1 micron prefilter, 1 micron carbon block and granular carbon filter that get my water down to around 15. I then pass it thru a mixed bed DI cartridge to get it to 0. My DI refill lasts about 5 to 6 months at 20+ gallons per week. You could get a DI cartridge or even one of those TapWater filters and get pretty good life out of either of them without buying an RO.

[saltwaterdave]

I am sorry I should have explained things better.I buy my top-off water from a machine in front of a local K-mart.I am just starting to wonder if they just run the water through a UV light and call it ro/di water.Or maybe they just need to change out the filters.I have been buying water from this machine for quite some time.Is 61 that bad? Or do I need to do something else?
David

[AZDesertRat]

If it really is RO water it should have at least a 90% removal rate minimum. That means their water should be somewhere around 14 or less. I would still invest in a tap water filter at a minimum if it were me. I had a typo in my original post, our water is actually 540 not 450, so my removal rate through the RO is above 97% still and my membrane is now 6 months old. My original membrane lasted 3 1/2 years using it for drinking water, ice maker and tank water.
I bought water from the local water & ice store until it exceeded $5 per week and then bought my own system. I started out with a $138 5 stage system from Costco and later added a higher flow rate membrane and a refillable DI cartridge. There are good deals out there at www.airwaterandice.com ? and my favorite is www.aquaticreefsystems.com . Some places give a 10% discount to members of some of the forums like here and ReefCentral.

[Unresistible Blue]

Is 61 that bad? Well, it all depends upon the specifics of your tank. Is it a Reef tank? FO?

How long have you been using this water? Are you having problems (e.g., algae) you would associate with excessive nutients in the water?

There are some people who argue RO DI is a waste, and they use dechloinated tap water, with TDS higher, and probably much higher than 61. When I've seen their tanks, they are usually heavy in algae.

Typical tap water TDS range from 100 to 500 or more. Post RO water is ypically 90%+ less than the tap water, and DI resin will take it down to 0 or 1.

Blue

[saltwaterdave]

It is what I call"a wanna be reef tank" But I working hard to get it right.
As far as the alage goes I am having a small slime problem,not a big problem,but a problem none the less,I don't like it.I do have one of those tap water filters,I think it is mostly a di unit,but the filter is spent,I might try a new filter and see what I get from that.I was always under the assumption that the TDS should be zero or close to it.
David

[AZDesertRat]

TDS should be 0 or close to it. I change my media when I reach 2 or 3.If you have a slime problem you probably have high phosphates. Try something like phos zorb or one of the other phosphate removal media. Water changes with higher quality water would also help this sitation. One source of phosphates is too much flake food. How often do you do water changes and how much? Do you use a protein skimmer? This helps water quality a bunch although some would argue on that. I run skimmers on 4 of my tanks from 15G up to 90G and wouldn't do without them.

[saltwaterdave]

phosphate's are zero,just tested them.I run a skimmer 24/7,Typically water changes are done every month,and I usually change out about 25 gallons on a 110 gallon tank,the tank had only been up and running since I think the first of April