RODI replacement filters

Tomoko Schum

Tomoko Schum

New member
Hi y'all,

Where do you buy your replacement filters lately? I bought my RODI unit from Filter Direct and I am thinking about getting the replacement filters from them, but I noticed that Lowe's and Sams also sell replacement RO membranes, carbon filters and such.

Any recommendation?

Tomoko
 
Lowe's & HD sediment filters are 5 micron. The ones that came with my RO/DI were .5 so I won't try to use them. I say this to point out that the RO membranes are probably not the same quality as what we require. I get my filters from Premium Aquatics or Marine Depot. I haven't needed a membrane yet but when I do I intend to get it from the same sources.
 
Do you guys use a flush kit to back flush your RO membrane?

Harry - how long has it been since you got your membrane? Do you just replace a sediment filter, carbon blocks and DI resin?

Tomoko
 
My Spectrapure came with a unit that tests the DI cartridge with a push button switch. I guess it's some kind of TDS meter. Green light= OK red light = replace. I push the button every day. When the red light comes on I order new cartridges: DI, sedient, and charcoal. There is also a setting on the unit to test the RO membrane. It has always been OK. I guess I buy new filters about every 10 - 12 months. I've never needed a membrane in 6 years.


Now, having said that, I think that the sediment and charcoal filters "protect" the membrane. If I had been using Lowe's 5 micron filters, yes, I would have needed another membrane.
 
I have the filters direct filter too, and need to replace the filters. Which housing holds the membrane? I see 3 across the bottom that are sediment filters, and then there are 3 on top, 1 of which is DI.
 
6Speed - Mine is a 6 stage unit (RO600DINT). I only have two housings on top, one of which is the membrane.

Filter Direct told me that their 100GPD unit is designed to use a 5 micron sediment filter. If a 1 micron filter is used in place of 5 micron one, the water flow reduces to the point it does not work efficiently through the membrane.

Harry - Thank you. 6 years is really a long time. I wish I knew how to test an RO membrane. The only thing I am using is my TDS meter. I am getting the reading of 6 - 7 for RO water, a bit less for my RODI water.

Tomoko
 
I get my replacements from Filter Direct. Tomoko as far as how to test your membrane its very easy.. Harrys unit just has built in TDS tester.. If you want to test the prefilters Add a T in the line after the filters but before the membrane. Put a ball valve on the output of the T.. Do the same thing after the Ro Membrane.. Test the water on all three outputs make a not of the different readings.. When the TDS starts going up change the prefilters.. HTH

I have the flush kit on both my units. Not sure if it helps all that much. One of my units came with it the older one didn't.. If you call filter Direct he will mail you one for about 15 Bucks They also sell inline TDS meters if you rater check the filters that way..

Will
 
Tomoko - My unit will test the primary DI cartridge and the RO membrane. It does not have a digital readout of any kind, only a red light/green light signal. It samples the water between the primary and secondary DI cartridges. When it tests red I order a new DI cartridge, sediment filter, and carbon filter. I replace the sediment and carbon filters, discard the primary DI cartridge, move the secondary DI cartridge to the primary position, and put the new DI cartridge in the secondary position. To test the RO membrane, you remove the primary DI cartridge and replace the empty housing, change a dip switch on the test unit and press the test button. It has always tested OK. I've never used a flush kit although I may order one if I ever need a new membrane.

PS, do you realize how many times I had to type "cartridge" in the paragraph above? I wish this thing had a spell checker.
 
<a href=showthread.php?s=&postid=7771656#post7771656 target=_blank>Originally posted</a> by H@rry
PS, do you realize how many times I had to type "cartridge" in the paragraph above? I wish this thing had a spell checker.
Click to expand...

I have a spell checker. Pay the yearly fee and you could too!
 
I have a spell checker. Pay the yearly fee and you could too!
Click to expand...

I could do that but then I couldn't buy new MH bulbs, filter cartridges (I typed it again), return pumps, powerheads, impellers, CR media, etc.
 
I should stop being lazy and disconnect a few ports to test the filters individually. A TDS meter helps to find out the general condition of the filters. I should replace the sediment filter and carbon filters in 6 months and see if that improves the life of the RO membrane much.

Replacing membranes every year adds up quickly. I need to do some calculations on the total cost and see if buying an inexpensive RODI unit is really money saving or not. I know Spectrapure replacement filter is not cheap. Their membrane costs twice or three times more than others, but if it last 5 times longer.... Of course Huntsville water is a bit softer (less sediments) than Madison water, but I don't think it makes 5 years difference in the life of membrane. Like I mentioned earlier, Filter Direct says that parts are not totally interchangeable because of the design basis (mainly the pressure) of the unit. If this is true, I may consider getting a Spectrapure unit. It may pay for the difference over a few years. The initial quote from Filter Direct for the replacement filters and membrane was just about the cost of their new unit (the new unit is cheaper if the pressurized storage tank and a faucet was not included.) They came down to the price offered by another vendor after a negotiation, but it's still a big chunk of money (almost $80 including shipping.) This is going to be every year?! Yikes!

Harry -

If you download a free Google tool bar, it comes with a spell checker. I have been using it for quite a while now. It works well. The tool bar also blocks a majority of annoying pop-up ad's.

How much do you spend for replacement filters (sediment and carbon filters and DI resin) every year?

Tomoko
 
FWIW,
The spell checker on the Google search bar works great -- I don't always use it, but it's very easy and always available at the top of my browser window.
Mariner
 
I'm seeing some bad advice here. For one prefilters and carbons have very little if any effect on TDS readings. The definition of TDS is Total Dissolved Solids. So that means they are down in the sub micron range and pre and carbons are 0.6, 1, 5 and 10 microns in size. The membrane and the DI are the only things that have a major effect on TDS. You may se a litle bit of difference but it is actually reading suspended solids that are being reduced and not dissolved solids.

As for the 1 micron prefilters the reason FD tells you that is they use an Applied Membranes RO membrane that requires 65 psi to operate efficiently whereas other vendors use Dow Filmtec membranes rated at 50 psi. That 15 psi makes a huge difference.

I am not a huge fan of 1 micron prefilters as most water systems will contain a certain amout of suspended sand or silt in their distribution system and it can plug them much quicker than a 5 or 10 micron. For a well system use a 10 micron prefilter followed by a 5 micron carbon blcok followed bya 1 micron carbon block. For a treated surface water system use a 5 micron prefilter followed by either a 5 or 1 micron carbon followed by either a 1 or 0.6 micron carbon for good filter life and water quality.

If you want the best quality replacement filters no one in the business comes close to Spectrapure, they do tons of bench testing on filters and only use the very best regardless of cost as they stake their reputation on them. Their filters are absolute rated and not nominal rated and there is a world of difference.

H@rry, look into the new Spectrapure Max Cap DI system, they are seeing 3.5x the life of regular mixed bed DI resin from this new system. I am bench testing one right now and I am really liking what I see!
 
So basically which filter kit do I need to order for this Filters Direct "Water General" RODI unit? I tried contacting filters direct through e-mail and never got a response...
 
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