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(edited)

The six month mark has just arrived after installing my rodi unit. The manufacturer recommends that the filters be replaced at 6 months. MY TDS meter is reading 0 at the OUT port. It is reading 81 at the IN port (I had installed a whole house sediment filter before the rodi unit since I am on a well). The IN port was reading 70 when I first replaced the whole house filter. Should I replace the filters? :why:

Edited by Highland Reefer
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The six month mark has just arrived after installing my rodi unit. The manufacturer recommends that the filters be replaced at 6 months. MY TDS meter is reading 0 at the OUT port. It is reading 81 at the IN port (I had installed a whole house sediment filter before the rodi unit since I am on a well). The IN port was reading 70 when I first replaced the whole house filter. Should I replace the filters? :why:

 

 

I don't replace my filters until I get a reading of about 5 on the TDS out. I really don't pay much attention to the IN readings - those are going to vary depending on what's being done to your water before it enters your house.

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I also just monitor the out TDS, but change out all the filters except membrane every year.

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Prefilters may increase TDS in some cases but they really do not decrease TDS.

 

How often you change prefilters depends on the source water and how much product you use. They are cheap and protect the more expensive RO membrane and DI resins so I recommend replacing them every 6 months, more often if you use very large volumes of water. I have also begun to change my sediment filter every 3 months.

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(edited)

What is the difference between a pre-filter & a sediment filter? I have seen some sediment filters that are 1 micron. It seems most of them are 5 & 10 microns. I am assuming that the disolved salts are below 1 micron in size.

Edited by Highland Reefer
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Prefilters include the sediment and carbon filters. There is sme debate about whether you should use a 1 or 5 micron sediment filter. I subscribe to the theory that a 5 micron sediment filter followed by a set of 5 micron, then 1 micron carbon filters is the best choice.

 

If you are at the BRK social this afternoon, look me up and we can discuss this in more detail.

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(edited)

I have a Kent Marine Maxxima-S rodi unit with three filters & the membrane. It has a 1 micron sediment filter, a .5 micron carbon block filter & a Silicamax di filter. I just priced these filters online and the total came to about $76.00 for all three. I have a 5 micron sediment filter in the whole house filter which is only about $4 at Home Depot.

 

Is there a cheaper place that I missed in my searches for the rodi filter cartridges?

Edited by Highland Reefer
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Try Air, Water and Ice. A lot of us use their products and occasionally even set up group buys. Over $800 in one order gets 15% off and free shipping. Their prices are great even without a group buy though, they are a WAMAS Premium Sponsor and they offer a 10% discount for WAMAS members. Here are some of their prices (before WAMAS discount):

 

Replacement pack $39.95

(1) 10 micron sediment filter

(1) 5 micron Coconut Carbon Black

(1) one micron Coconut Carbon Black

(1) Full size vertical color changing DI Cartridge

 

6-pack of prefilters $29.95

(2) Sediment 10 Micron

(2) Coconut Carbon Block 5 Micron

(2) Coconut Carbon Block One Micron

 

See the vendor discount thread in Vendor News for the discount code.

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(edited)
Try Air, Water and Ice. A lot of us use their products and occasionally even set up group buys. Over $800 in one order gets 15% off and free shipping. Their prices are great even without a group buy though, they are a WAMAS Premium Sponsor and they offer a 10% discount for WAMAS members. Here are some of their prices (before WAMAS discount):

 

Replacement pack $39.95

(1) 10 micron sediment filter

(1) 5 micron Coconut Carbon Black

(1) one micron Coconut Carbon Black

(1) Full size vertical color changing DI Cartridge

 

6-pack of prefilters $29.95

(2) Sediment 10 Micron

(2) Coconut Carbon Block 5 Micron

(2) Coconut Carbon Block One Micron

 

See the vendor discount thread in Vendor News for the discount code.

 

 

 

If I have this figured out right, you are saying to switch my current setup that came with the Maxima, even though the particle size only goes down to 1 micron instead of .5 microns & this will be just as effective. I read the suggestions on Air, Water & Ice & they say this is all you need. Since I am using a whole house filter in front of my Maxxima, I can put the 10 micron sediment filter in it; put the 5 micron carbon block in the 1st stage of the maxima; put the one micron carbon block in the 2nd stage of Maxxima & replace the 3rd stage with the DI cartridge. This would decrease my cost from $76 down to about $45.00. Sounds good to me as long as I continue to get 0 readings on my TDS meter. Ybe, if your wrong, just remember that this exterminator specializes in husbands, wives, girlfriends, boyfriends, dogs, cats & reefers that give out bad advice. :biggrin:

 

I would think that since I am at the 6 month mark, I would only have to replace the prefilters. What do ya think?

Edited by Highland Reefer
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Measure the TDS of your tap water and just after the prefilters (after sediment and carbon but before RO and DI). I'll bet you'll find that the TDS readings are the same or that the post-prefilter sediment reading is actually higher. Prefilters do not typically lower TDS readings. This is done by the RO membrane and DI resins.

 

AWI believes in using a series of cartridges with progressively smaller pore sizes. This is supposed to help prevent clogging of the prefilters. Their setup has worked great for me for many years. It has also been proven to be effective in areas where the city is using chloramines. In fact, the city employee that tested the output was very surprised at the quality of the output water.

 

Here's my schedule for replacements:

sediment filter - every 3 months

carbon filters - every 6 months

DI resin - yearly or when I see either a TDS higher than zero or the color changing resin is ~75 changed

RO membrane - When I begin to see higher TDS after the RO membrane. Under normal use and with proper care (changing carbon filters regularly), RO membranes should last for 2 or more years.

 

I use a label maker to date the filter chambers after each change. 'Makes it easy to remember when the next change is due.

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I could use some more filters too. If there's enough interest, I'll set up another group buy when I return from vacation next week.

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I could use some more filters too. If there's enough interest, I'll set up another group buy when I return from vacation next week.

 

 

I'd need about $100 plus worth of goodies

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I am using a whole house filter in front of my Maxxima, I can put the 10 micron sediment filter in it; put the 5 micron carbon block in the 1st stage of the maxima; put the one micron carbon block in the 2nd stage of Maxxima & replace the 3rd stage with the DI cartridge. This would decrease my cost from $76 down to about $45.00.

 

I just read this again. Your cost would actually drop to $39.95 - 10% WAMAS discount + shipping. You could save even more long-term by buying the 6-pack plus a DI resin cartridge and a resin refill kit (four refills). BTW, all of AWI's resin cartridges are refillable.

 

I may set up an AWI group buy in a couple of weeks. I'll have to confirm that they are still offering 15% discount and free shipping for orders over $800. If so and if we can reach that target (we almost always do), that will save you even more money.

 

IRT 1 micron vs .5 micron carbon filters or the difference between granular activated carbon vs standard carbon cartridges, my experience is that all effective whether your water has chlorine or chloramine as long as you replace the cartridges before they are exhausted. None are effective if you don't replace the carbon filters regularly though and regular replacement is even more important if your water supply is treated with chloramine. JMHO based on personal experiences...

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Thanks Ybe for all the great info. I will wait till you get back and join in the group buy if there is enough interest. I am also looking at the electronic ballasts & bulbs they sell for a frag tank I am putting together. The discount would help even more. :biggrin:

 

:cheers:

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im in also. i think they will work with my filter direct setup.

 

 

FWIW, The filters sold by Air Water Ice are of standard sizes ;)

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