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Elo500
08/15/2015, 07:34 AM
My tap water has high tds (450). Do I need anything extra on a unit for high tds? Is the gpd rating important if I just have small tanks? What's the difference between the different brands, or are they all the same?

dkeller_nc
08/15/2015, 07:44 AM
Generally speaking, 450 TDS isn't astronomical, and about the only thing that will be different from those of us that live in the East and have a TDS < 100 ppm is that you may find that you have to replace your DI resin a little more often. As for and advisable "extra", I would simply order an add-on membrane flush valve so that you can be diligent about flushing the RO membrane to prevent fouling from precipitated minerals from your water.

The differences between RODI units are generally more about price level than brands - the higher priced units may have brand-name RO membranes (such as Dow FilmTec) and perhaps better grades of carbon and DI resin. They will also have "extras" like a membrane flush valve and an integrated TDS meter.

A couple of good sources - Buckeye Hydro (a forum sponsor) and Bulk Reef Supply.

Edz2891
08/15/2015, 07:55 AM
If you decide on Bulk Reef Supply they have a ton of helpful videos on youtube. And they usually run some nice sales on their units.

ClownsRCoo
08/15/2015, 08:10 AM
If your budget is borderline one of the nicer units that bulk reef supply sells I would recommend holding off until Black Friday. You will save a lot and be able to get the nicer one you are wanting for a price in your budget.

Difference is internal components like first poster said. GPD is really for convenience. These things fill a lot slower than you might think so it really is again a convenience to not have spend so much time waiting for the water.

For high TDS like that you are prob going to have to run a DI canister or 2. I doubt even a 4 stage unit with no DI can bring you down to 0 TDS. My tap TDS is in the 350's and before my DI my 4 stage system can only bring it down to 4.

shifty51008
08/15/2015, 09:17 AM
A couple of good sources - Buckeye Hydro (a forum sponsor) and Bulk Reef Supply.

buckeye hydro is still a sponsor here, I just started useing their MAXR membrane and couldn't be happier, brought my tap water from 531 ppm to 4 ppm pre DI

Elo500
08/15/2015, 09:29 AM
What are differences between 3 stage, 4 stage, 8 stage etc? Is it just additional level of filtration?

ct3737
08/15/2015, 09:30 AM
I use purewaterclub.com rodi. Don't fall into the hype they are all the exact same filters and setups. Buying one labeled aquariums will just make you pay more for the same water. Get one 50-100 gpd, a brute trash can and a float valve and forget about it. I always have water on hand, throw in a air stone to keep it moving.

shifty51008
08/15/2015, 09:33 AM
What are differences between 3 stage, 4 stage, 8 stage etc? Is it just additional level of filtration?

the more stages are just a marketing gimmick, you only need a 3 or 4 stage depending on if you have chloramines. 1 sediment, 1 carbon, ro membrane, and DI.

shifty51008
08/15/2015, 09:36 AM
I use purewaterclub.com rodi. Don't fall into the hype they are all the exact same filters and setups. Buying one labeled aquariums will just make you pay more for the same water. Get one 50-100 gpd, a brute trash can and a float valve and forget about it. I always have water on hand, throw in a air stone to keep it moving.

there are a couple of named brand filters that use much better filters than others, they even hand test their membranes. buckeye hydro and spectrapure just to name a couple

Lowlow23
08/15/2015, 10:16 AM
I'm new to this hobby is a rodi nessisary or just a extra help? TIA

Harry_Y
08/15/2015, 10:38 AM
I'm new to this hobby is a rodi nessisary or just a extra help? TIA

Necessary

shifty51008
08/15/2015, 10:53 AM
I'm new to this hobby is a rodi nessisary or just a extra help? TIA

Do you need rodi water to have a sw tank? No but the stuff that comes in tap water can limit the stuff you keep and algae but it depends on the quality of tap water in your area some is much better than others. Useing rodi water also eleminates alot of other problems. So while it isnt nessasary it is highly reccomended.

Water is the main thing in a fish tank so why skimp on that area.

dkeller_nc
08/15/2015, 12:45 PM
What are differences between 3 stage, 4 stage, 8 stage etc? Is it just additional level of filtration?

Essentially, it's additional capacity. There are 4 main "types" of filtration used in one of these units in this order: particulate filtration (lumps n chunks removal), carbon filtration (chlorine and/or chloramine removal), Reverse Osmosis (dissolved mineral removal/reduction), and deionization (remaining dissolved mineral removal to achieve 0ppm TDS).

Additional "stages" are simply additional beefing up of one of the particulate, carbon or deionization stages. For example, my system is technically 6-stage; I have 2 particulate filters up front (a 2 um and a 0.1 um), 2 carbon filtration stages (loose carbon in a cartridge plus a carbon block), an RO stage, and a final DI stage.

The extra particulate filtration and carbon stages just add capacity to my system and require less frequent change-out.

Elo500
08/15/2015, 01:07 PM
What's a decent price for a used 4 stage? I suppose it depends on how much filter is left. ....

shifty51008
08/15/2015, 01:18 PM
Prices can range but around 150.00 to 200.00 is a good price. The biggest things you want on a rodi unit is a prsssure gague and a tds meter, with those 2 things you can check how your filters are working and when to change them out. Price can go up depending on if you need a booster pump though.

Johnseye
08/15/2015, 01:32 PM
I had a high tds like yours. Put in what is essentially a 5 stage Spectrapure with flush. 2 meters. 0 tds now. Rock solid, dependable. My pressure was low so I did add a booster pump as well.

http://spectrapure.com/RO-RODI/RODI-SYSTEMS/MaxCap-Manual-Flush-90-GPD-RO-DI-System

dkeller_nc
08/15/2015, 01:33 PM
What's a decent price for a used 4 stage? I suppose it depends on how much filter is left. ....

Yes indeed. The cost of the RO membrane, filters and DI resin is most of the cost of the unit. For example, this (http://www.bulkreefsupply.com/brs-4-stage-value-plus-ro-di-system-75gpd-1.html) unit from BRS has all the bells and whistles (flush kit, TDS meter, pressure gauge) and all brand-new filters and cartridges for $200.

You can spend another $100 and get a 6-stage with everything you could need, but I would only suggest that to someone with a large tank with high water demand.

Opus123
08/20/2015, 09:53 AM
I would go with this one:

http://spectrapure.com/Refurbished-90-GPD-RODI-System

Don't let the "refurbished" bother you, you will get all new filters. I've been using the same RO unit for over 20 years and still using the same filter housings. Started out as a Kent 25/gpd unit and I've changed out the filters and added a DI cartridge to it plus a spectrapure 90/gpd membrane. So even if you buy the one I linked or any of the other suggestions, you can easily make changes to the setup.

My only other suggestion for you is to find out your water pressure. To run efficiently the RO unit should be 60 or above. If it is lower you will probably want to invest in a booster pump.

Buckeye Hydro
09/05/2015, 11:18 AM
Essentially, it's additional capacity. There are 4 main "types" of filtration used in one of these units in this order: particulate filtration (lumps n chunks removal), carbon filtration (chlorine and/or chloramine removal), Reverse Osmosis (dissolved mineral removal/reduction), and deionization (remaining dissolved mineral removal to achieve 0ppm TDS).

Additional "stages" are simply additional beefing up of one of the particulate, carbon or deionization stages. For example, my system is technically 6-stage; I have 2 particulate filters up front (a 2 um and a 0.1 um), 2 carbon filtration stages (loose carbon in a cartridge plus a carbon block), an RO stage, and a final DI stage.

The extra particulate filtration and carbon stages just add capacity to my system and require less frequent change-out.
Darn good way to explain this!

thetedinator
09/05/2015, 12:38 PM
I had a high tds like yours. Put in what is essentially a 5 stage Spectrapure with flush. 2 meters. 0 tds now. Rock solid, dependable. My pressure was low so I did add a booster pump as well.

http://spectrapure.com/RO-RODI/RODI-SYSTEMS/MaxCap-Manual-Flush-90-GPD-RO-DI-System

I did the same thing as Johnseye. My water quality is bad (~400 TDS) and with the drought I wanted to minimize waste so I am using a Spectrapure RO/DI with a Smart Buddie booster. Very happy.

powder_blue
09/05/2015, 01:49 PM
I highly recommend Spectrapure MaxCap 90. Love mine and they are very active on the sponsor forum here.