RO/DI questions

[PSH]

Well I finally bit the bullet and ordered a RO/DI. This is the unit I got http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1
Everything is hooked up and it's making water. The problem is I don't have a TDS meter. I was looking at this one http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1
Will it do what I need it to do? I was hoping the LFS would have a TDS meter but no luck. Is this water safe to use or should I wait and have it tested first before I use it?

Also I am using a rubbermaid garbage can to hold the water (as I have seen others use) what is the easiest way of getting the water back out?

[motorslave]

You can get inline TDS meters for a good price and I believe Premium Aquatics has them. The first 5 or 10 gallons from new filters should be dumped. but after that you should be fine! deopending on the volume of your system You may want to consider getting a second set of filters for backup!

Robert

[Geoff]

some people just use pitchers for water removal. others put a small pump capable of pumping at least the height of the garbage can and using that.

G~

[Unresistible Blue]

At some point you may want to get rid of the horizontal DI housings, and doa little replumbing of the unit to replace your second carbon stage with a vertical DI.

[Geoff]

what is better about being vertical than horizontal. is it the settling problem of the resin? can any DI container be rotated?

G~

[Unresistible Blue]

Horizontal DI housings are a design intended to minimize the original cost or the system - you should be prepared for the tradeoffs. Horizontal DI units typically contain 8 oz. to 16 oz. of resin. Typical vertical DI cartridges contain 20 oz of resin. Obviously the more resin contained in the housing the longer it will last and the better treatment it will provide.

Some horizontal DI housings are not refillable - you'll therefore have to pay for a new housing every time you need to replace the DI resin. The cost of repeatedly replacing the horizontal housing will far outweigh any money saved up-front in purchasing the unit.

Perhaps most importantly, horizontal DI housings are a less than ideal arrangement for water treatment. DI resin beads shrink through normal use over their life span. You'll note that a cartridge that was full when new can sometimes have a ¼ inch of empty space in it when fully expended. When DI resin settles in a horizontal housing, it leaves a pathway (of least resistance) along the top of the housing where water can flow while coming into minimal contact with the DI resin.

You’ll note that the output from the DI housing is at the center of the end of the housing. Depending upon how your system is configured, RO water may enter the DI housing in port, fill up the housing until the water level reaches the out port (i.e., fill up the bottom half of housing), and then exit the DI housing. Your RO water has been in contact only with half the resin in the housing.

[Geoff]

Thanks!!! that is what i thought, always good to get confirmation.

is there any reason why you could not rotate the horizontal units? at least you can hopefully get some more life out of it before it needs to be replaced.

G~

[Unresistible Blue]

As an interim measure - yes - I'd rotate it. Unfortunately they don't come with any sort of mounting bracket to facilitate this. Keep an eye on your tds levels...

And get rid of the GAC after the resin!

[Geoff]

i thought the DI was the last in line anyway. is it not on some units?

G~

[Unresistible Blue]

Originally Posted by Geoff

i thought the DI was the last in line anyway. is it not on some units?

G~

You bet. Having GAC after the DI is a curious configuration...