TDS at 11, DI Resin out I think

L

lmcnutt

I've got a kent marine maxxima unit. I've lost the paper work and don't know what to get to refill my DI cartridge. Can anyone shed some light on this?

Larry
 
Yep that seems to fit the unit I have. Thanks for pointing me to this. Is 29.99 a decent price? Anyone else (plano/frisco) need one, maybe we can split the shipping cost?
 
I have the Kent RO/DI as well, and ditched the pre-made DI ages ago...

There are several sources where you can buy re-useable DI cartridges, and then get the DI resin in bulk. When the resin is used up, instead of replacing the cartridge, you take the cartridge out, empty it, and put fresh resin in...

The refillable DI cartridge is $8, and the DI resin is $38 for enough DI resin to refill the cartridge 4 times. I.E. For under $50 you get everything you need to "make" 4 DI cartridges, and it'll even be cheaper next time since you'll only need to buy the resin...

(If you decide to go this route, I highly recommend buying two of the refillable cartridges though, that way you'll always have one in service, and the other can be out to completely dry and ready to be filled as soon as it's needed)

Just as examples, this is the place I got my most recent order of DI from:

http://www.thefilterguys.biz/de-ionization.htm

And here's where I ordered from the time before that, but there are tons of places to get it from (Even good 'ole ePay)

http://www.airwaterice.com/product/REFILLDIPACK
 
I ordered from the filterguys, and It was shipped the same day I ordered it.
I got it in only 2 days, and the quality is very nice.
 
@lmcnutt wrote:
Thanks Brian said:
Really impossible to predict, it's dependent on how high the TDS is of the water coming outta your RO, how much water, the temperature of the water, how much CO2 is dissolved in the water, the phase of the moon... :) (Kidding on the phase of the moon bit, but it wouldn't suprise me)

There's something wrong with my RO, and my RO product water is coming out near 100 TDS, but the DI is lasting about a month before my DI product water's TDS starts to rise about 0... With a properly working RO, the DI cartridge should last just as long as a factory made DI cartridge will last in your system though...
Click to expand...
 
I don't know, this is my first cartridge. It lasted about 6 months. I'll bet I haven't run 500 gallons through it yet. I did notice my input TDS before any filtration was 400. Must be the lack of rain. I was thinking before it was in the 200's.
 
The DI should last about 12 months normally. The prefilter set should be replaced at 6 months (or twice a year).

Of course, it comes down to how much water you make too. I make about 30g of water a week, or 200g a month with water change water.

Brian, something is wrong with your unit if it comes out at 100 after the RO. What is the TDS going into the unit? How old are your prefilters? How much waste to pure water are you producing?
 
Marc - My source TDS is currently running 400-500... The waste water is fed straight to drain, so I don't have an easy way to measure it, but might do so if I don't get this figured out.

The pre-filters are 1-2 months old, and the RO is brand new. After my experience last year with a non-fully seated RO cartridge, I'm gonna take it apart and re-seat everything, just haven't had a chance to do so yet...

(Also gonna juggle the in-line TDS meters around to make sure it's not just one wonky probe reading wrong, but I don't think that's the case due to the rate of DI exhaustion)
 
Alright, well I purchased the single serving in the cartridge for $18.00 + $9.50 shipping.

Noting the post above, what is an acceptable TDS post RO pre DI? I want to check that before I change all the filters, although I believe they all need it.

Thanks!
 
You'd need to know the rejection rate (I think that's what it's called) for your RO membrane. Mine's a 98% rejection rate, so theoretically, for every 100 TDS going in, the product water SHOULD be 2 TDS... Most membranes I've seen are between 90% - 98% rejection rate...

(Marc or anyone else, feel free to call me on it if I'm talking out my backside on this one!)
 
I try to stay on top of that topic, but since it isn't daily conversation, I do get it mixed up some times. That sounds about right to me.

I think to figure out the rejection rate of your unit currently, take the TDS of the RO's output, and divide it by the TDS of the water going into the unit to get the rate of rejection.
 
Just for reference, I finally got my RO producing respectable TDS again (30 or under with 400+ source water).....

I'd had my system plumbed with a T on the line that runs from the RO to the DI, and the T fed a pressure tank for the fridge... Never could get good pressure out of it though.... Probably need to get a permeate pump.

But until I can get a permeate pump, I moved the T to feed the fridge after the carbon block BEFORE the RO... Almost immediately my RO product water TDS plummeted down to where it should be. So evidently my RO just REALLY didn't like working against the back pressure of the pressure tank...
 
You must log in or register to reply here.
Top