Researching some RO/DI Units for purchase

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Krypt

Aquarium Advice FINatic
Joined
Jan 11, 2010
Messages
752
Location
Holley, NY
I've been looking into getting a RO/DI unit to cut back my Walmart trips. I was doing a little bit of math and I'm not sure if it's a good investment to buy a personal one.

At my Walmart, I can get RO water @ $.0.35 a gal. For my normal water change of 10-15 gal and my top off water I need approx 20 gals every two weeks and it only runs me about $7.00.

The RO units I'm looking at on the sponsored site and Dr.Fosters are in the $120.00-$250.00 price range and after I factor in replacement cartridges I'm looking at the initial cost plus an extra $25.00-$50.00 every 6-9 months.

So my totals for the first year would be $84.00 from Walmart and $170.00-$300.00 for the RO/DI unit. After the first year the cost of my RO/DI unit will still be $50.00 - $100.00 with Walmart staying at only $84.00 (providing they don't bump the price up)

My question is, is the difference in overall price really worth it? I realize the personal filters have a slightly higher filtration rating but I just don't know if it's really worth it.
 
check ebay... you can get quality ro/di units in the $100 range. Look for 75gpd or less (the 100gpd membranes have a higher rejection rate). Just ask and make sure they use standard replacement filters so you can get them most anywhere and not be tied to one specific vendor.

IMO it's well worth it. Some things you didn't figure into your equation was the cost of gas to get you there and back and whatever value you place on your time.

I don't understand the 'personal filters have a slightly higher filtration rating'.. an RO/DI filter will make you 0 TDS water.. doesn't get any more 'filtered' than that..
 
check ebay... you can get quality ro/di units in the $100 range. Look for 75gpd or less (the 100gpd membranes have a higher rejection rate). Just ask and make sure they use standard replacement filters so you can get them most anywhere and not be tied to one specific vendor.

IMO it's well worth it. Some things you didn't figure into your equation was the cost of gas to get you there and back and whatever value you place on your time.

I don't understand the 'personal filters have a slightly higher filtration rating'.. an RO/DI filter will make you 0 TDS water.. doesn't get any more 'filtered' than that..

My Walmart is only about a mile down the road and plus being a family man I'm there a couple times a week anyway lol. What I meant about the higher filtration rate was that with anything from Walmart that isn't clothing or DvD's usually only functions at about 85% efficiency so I figured their water would be the same where as a personal one I could ensure a higher efficiency by maintaining the cartridges myself.

The RO/DI unit I was really looking at was this one:
http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4395+4418+12093&pcatid=12093
I'm always iffy about getting equipment from Ebay. If it breaks after a month I don't have anyway to return/exchange it.
 
Give the thread some time .. members will start posting links to their units and their experience..

Ever stick a TDS meter in their water and see what you're getting? A tds meter is a good investment too.
 
I bought mine on Ebay a few years ago from FilterDirect. I got the unit that also has a storage tank and faucet for drinking the RO water and a seperate outlet for the RO/DI water for my tank. They take standard replacement filters that can be found anywhere.
REEF DRINKING RO DI REVERSE OSMOSIS WATER FITER SYSTEM - eBay (item 350185952913 end time Jan-26-10 19:50:35 PST)

This unit is the RO/DI without the storage tank.
AQUARIUM RO 2DI REVERSE OSMOSIS WATER FILTRATION SYSTEM - eBay (item 350185950353 end time Jan-26-10 19:36:55 PST)
 
Thanks Capt for the product referral. I'll have to weigh the pro's and con's with the Mrs. and if shes on board, then I'll be scooping one up, and thank you too Mel for the advice, I hadn't thought about exactly what was in the water.
 
check this one out. I have the 5 stage RO/DI unit and dual TDS meter. 1 year later I haven't had to replace a cartridge or resin and my TDS is 0 an my resin is almost completely bluethat means it is good It turns brown when it expires. I think your estimate of cost on replaceing the cartridges is WAY over estimated. it really depends on the water quality going into the system. It is pretty good where I am.

75 GPD RO/DI 4 Stage Standard System - English

$159.00

and the dual TDS meter. $29.00

Dual inline TDS meter DM-1 HM Digital - English

and the 5 stage filter kit. $32.00

5 Stage Standard Replacement Filter Kit - English

You don't have to buy a new RO membrane everytime you replace your cartridges. Just flush it every so often and it is good for a while. by those numbers it looks like the RO/DI unit is MUCH cheaper than wal-mart in the long run.

The convience has a lot of value also.
 
check this one out. I have the 5 stage RO/DI unit and dual TDS meter. 1 year later I haven't had to replace a cartridge or resin and my TDS is 0 an my resin is almost completely bluethat means it is good It turns brown when it expires. I think your estimate of cost on replaceing the cartridges is WAY over estimated. it really depends on the water quality going into the system. It is pretty good where I am.

75 GPD RO/DI 4 Stage Standard System - English

$159.00

and the dual TDS meter. $29.00

Dual inline TDS meter DM-1 HM Digital - English

and the 5 stage filter kit. $32.00

5 Stage Standard Replacement Filter Kit - English

You don't have to buy a new RO membrane everytime you replace your cartridges. Just flush it every so often and it is good for a while. by those numbers it looks like the RO/DI unit is MUCH cheaper than wal-mart in the long run.

The convience has a lot of value also.


Thanks for the info Daniel, after reading these and what seemed to be like an endless night of negotiation with the mrs. lol, I'm going to be picking one up, particularly the one you use Daniel so thanks again!
 
I've been looking into getting a RO/DI unit to cut back my Walmart trips. I was doing a little bit of math and I'm not sure if it's a good investment to buy a personal one.

At my Walmart, I can get RO water @ $.0.35 a gal. For my normal water change of 10-15 gal and my top off water I need approx 20 gals every two weeks and it only runs me about $7.00.

The RO units I'm looking at on the sponsored site and Dr.Fosters are in the $120.00-$250.00 price range and after I factor in replacement cartridges I'm looking at the initial cost plus an extra $25.00-$50.00 every 6-9 months.

So my totals for the first year would be $84.00 from Walmart and $170.00-$300.00 for the RO/DI unit. After the first year the cost of my RO/DI unit will still be $50.00 - $100.00 with Walmart staying at only $84.00 (providing they don't bump the price up)

My question is, is the difference in overall price really worth it? I realize the personal filters have a slightly higher filtration rating but I just don't know if it's really worth it.


check yer math. $7X26=$182 yearly. + time and effort vs. water bill.

I have TDS metered my water from the store RO and two different machines came in at 12. this water is not DI as you wouldnt drink DI and 12 is ok for drinking but not optimal for reef.
 
Just to chime in here, I have the Typhoon III from airwaterice.com I replace the carbon filters annually, the sedment filter and DI resin quarterly (or as needed) and I just replaced my 5 year old membrane. A TDS meter is a must.

I prefer the clear cannisters or at least a clear cannister for the sediment filter so you visually see when it needs to be replaced. AWI reccomends a 10 micron seidment filter, followed by a 5 micron carbon, followed by a 1 micron carbon before the membrane. I also have the color changing DI resiin but only change it when I see TDS above 0.

Also, the 100 gpd membrane only has a 90% reject rate while the 75 and 150 gpd membranes are higher.

HTH
 
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