Is this reading right?

[DongShenYin]

I got a Hanna TDS 1 meter off of eBay. It says it's already calibrated before it left the factory. The TDS reading I got out of my tap was 46. Is that possible??? Do I still need RO water if it's right?

 

[jackson6745]

My TDS from the tap reads 48-52, yes you still need RO. The water comes out of my RO/DI at 0ppm TDS

 

[DongShenYin]

Whoops... I meant an RO unit as opposed to the DI until the TWP is supposed to be.

 

[jackson6745]

say what?

 

[DongShenYin]

Since the tds is so low, can I just use a DI unit instead of a RO/DI unit?

 

[Mantis806]

i got the same tds reading yesterday when i tested my water. my RO water came out to 0. it's ok to use a DI. it's better than water, but it probably won't be as good as RO water. i read on sevaeral threads on RC that if one had to choose b/n RO and DI, they would pick RO. i've been using the tap water filter, which is essentially just a DI cartridge. the problem is that DI filters get exausted quickly. so if you have a big tank, it's better to use RO in the long run, since it lasts much longer. the tap water filter i used was only good for a few months. HTH.

 

[jackson6745]

A DI will give you quality water(sometimes) out of the tap. I have measured 0-10 TDS from the Aquarium Pharm TWP. The problem is because the quality of tap water will fluctuate from time to time, so will the quality of your DI water. In an RO/DO the water is pure all the time. If you plan on housing SPS I would say the RODI is a must. For a softie tank yeah, you can get away with the twp

 

[DongShenYin]

Hm so where's the best place to get a RO/DI system? eBay ones are cheap, but I'm not so sure I want to buy from a seller that I can't find again when I need to replace filters.

 

[jackson6745]

Airwaterice.com

 

[DongShenYin]

Thanks!

 

[House of Laughter]

or www.aquaticreefsystems.com

Good prices and phenomenal customer service.

They have some budget items as well. Take a look

House

 

[DongShenYin]

Thanks too! What's the difference between them?

 

[bad coffee]

Most RO/DI units use the same filters. Only once in a while will you run into a non-standard size. Something to think about when you purchase one.

I get my prefilters at home depot. They're cheap enough that I don't save anything by ordering online and paying shipping.

HTH

BC

 

[jackson6745]

BC what does homedepot charge for the micron filter blocks?

 

[House of Laughter]

FYI they are typically .5 micron blocks and wear down your Carbon and DI as well as TFC Membranes. I use the 1.0's to get more life out of the others.

House

 

[jackson6745]

thatnks Jim, I use the 1 micron as well and it turns redish with rust in 2 weeks. How often do you change yours. I know you said the TDS is pretty high by you so you must change often?

 

[Unresistible Blue]

Let's back up a little. You question (I think)- "If my tap water is only 46 ppm tds, can I use just DI, rather than RO and DI?"

You could do that, but I don't think you'd be thrilled with the life span of the DI resin. It wouldn't be terrible, but not great either.

A better choice would be to use a RO only. With a 98% rejection rate you'd produce water at less than 1 ppm - which is fine for your reef tank, and you'd avoid the cost of DI resin.

Get a simple three stage RO: sediment filter, carbon block, RO membrane.

 

[Unresistible Blue]

Originally posted by bad coffee:
Most RO/DI units use the same filters. Only once in a while will you run into a non-standard size. Something to think about when you purchase one.

I get my prefilters at home depot. They're cheap enough that I don't save anything by ordering online and paying shipping.
BC

A different take on this: Many times the most important differentiator between systems is the difference in the filters. For instance, many residential units have sediment filters with a pore size of 10 microns. This is what you may find at home depot. There are filters with smaller pore sizes to be had.

Carbon blocks vary in their pore size and chlorine capacity (expressed in gallons). You generally get what you pay for here.

Regarding filter size:
There is typically little if any information provided by original equipment suppliers in this regard. Fortunately this is an easy riddle to solve for RO/DI system owners! Filter cartridges (e.g., sediment filters, carbon block filters, GAC cartridges, DI resin cartridges), and therefore the internal dimensions of the housings that contain them, come in only a few standard sizes. The sizes are very different from each other, so you don?t have to worry about making precise measurements of your housings.

Housings are typically designed to accommodate filters of one of the four following dimensions:
2.5? diameter x 10? length
4? diameter x 10? length
2.5? diameter x 20? length
4? diameter x 20? length

Nearly all residential RO/DI systems used in the marine aquarium hobby are designed to utilize 2.5? diameter x 10? length filters. Now ? one note just to complicate things ? you?ll sometimes see filters for these housings that measure 9 3/4? or 9 7/8? in length ? no problem! They will fit just fine in standard 10? housings.

Also note that there are filters with dimensions other than those listed here, but there is a very high likelihood your system uses the 2.5? x 10? filters.

Blue

 

[Melt]

if you're buying from www.aquaticreefsystems.com mention that you're a reefcentral member and you get a discount..after he give you the price..

 

[DongShenYin]

That's where I got mine from. I bought their 3-stage budget 75gpd RO unit for less than $150 including shipping. All I have to do now is hook it up. Thanks everyone!