RO/DI Units from EBAY which one?? Pls Help.

Re: TDS Meter

Re: TDS Meter

<a href=showthread.php?s=&postid=6532008#post6532008 target=_blank>Originally posted</a> by sterlruth
Cheaper is not always better.

Make sure you have TDS meter to measure the output. You should have a reading of 0 and with the E-bay units I could never get a 0 reading. The sellers are great but keep in mind why your buying the RO/DI in the first place. Pick your poisen carefully.


Steve
Click to expand...

What TDS meters are good? i just bought one from ebay.
is this any good?

http://cgi.ebay.com/TDS-METER-water...itemZ4409026386QQcategoryZ20684QQcmdZViewItem

this is what i bought.
 
Cheaper is not better in the case of RO/DI. You really do get what you pay for and the best value hands down is the Typhoon III from www.airwaterice.com . You get a true 75 GPD RO membrane and not a 90% rejection rate nano filter like some others sell. You also get a TDS meter, Pressure gauge, true 10 standard size canister and refillable cartridge DI filter that holds 24 oz of resin and not a hollow tube that claims to ba a DI filter and only hold 6 oz or so of resin and has horrible flow characteristics so wastes resin. You also ge ta completely preassembled unit with clear easy to read directions and not a box full of parts and some poorly translated directions that leave you confused. The customer support and warranty can't be beat and all components are top quality.
You should also consider www.buckeyefieldsupply.com and www.purelyh2o.com, all three use Dow Filmtec 75 GPD RO membranes and have true refillable DI filters. Prices and quality are comparable on all their units showing none of them are trying to rip anyone off, like I said you really do get what you pay for and quality does not come cheap. Those units are cheap for a reason and you will end up paying more and being frustrated in the end.
 
Re: TDS Meter

Re: TDS Meter

<a href=showthread.php?s=&postid=6532008#post6532008 target=_blank>Originally posted</a> by sterlruth
Cheaper is not always better.

Make sure you have TDS meter to measure the output. You should have a reading of 0 and with the E-bay units I could never get a 0 reading. The sellers are great but keep in mind why your buying the RO/DI in the first place. Pick your poisen carefully.


Steve
Click to expand...

You get what you pay for!!!!! I think everytime people cut corners it turns around and bites them in the rear!! at least in this hobby anyway! That's just my opinion anyway.

Here's a link to a TDS meter, it seems to be a higher end product. It's the one I've been thinking of buying, plus there is alot of cool techie stuff on this page also
http://www.ambientweather.com/execwaexcome.html
 
For those who scoff at the eBay units and say "cheaper isn't always better", the two 6 stage RO/DI I've gotten have always read zero TDS when straight out of the units. In the real world, most people don't want to blow an extra $200 if they don't need to... it just comes down to whether or not the membranes are professional grade.
 
Spectrapure is indeed the Cadillac or Mercedes of the RO industry but you pay for that service. I highly recommend them but for normal water conditions do not consider them as good a value because of that cost. If you have special water conditions there is no one better. Their units are bulletproof.
 
Why does everyone keep saying there is a $200 price difference? The e-bay units average around $99 to $150 or so and the Typhoon III is $199. The difference in price is the better membrane, true DI refillable DI filter, TDS meter, pressure gauge, float valve, additional acid washed solid carbon block, assembly, warranty and technical support, clear directions......... the list goes on and proves the point, " You get what you pay for". Add up the cost and value of all those items and it far outweighs the price difference.
 
I think the thing that people have to understand is that there is a relatively large markup after RO's are built; quality units are not hard or expensive to build. I got my last one from my LFS, who buys them wholesale from a professional water purification company that makes very nice units, and he sells the same 6 stage, 150 GPD units, for $200 retail, but sells them to me for $80, the same price he pays for them. At that price, it's cheaper for me to buy a new one when the membranes die than go through the hassle of buying new ones & changing them out myself.
 
AZ, Spectrapure, Neptune and several other name brands sell 150GPD, and you can ask around here, I've seen a few other RC members who have this rating system.
 
<a href=showthread.php?s=&postid=6533424#post6533424 target=_blank>Originally posted</a> by AZDesertRat
Why does everyone keep saying there is a $200 price difference? The e-bay units average around $99 to $150 or so and the Typhoon III is $199. The difference in price is the better membrane, true DI refillable DI filter, TDS meter, pressure gauge, float valve, additional acid washed solid carbon block, assembly, warranty and technical support, clear directions......... the list goes on and proves the point, " You get what you pay for". Add up the cost and value of all those items and it far outweighs the price difference.
Click to expand...

I have been reading alot of good things about the Typhoon III RO/DI unit on this fourm. If I ever needed to replace my existing unit(Kent Marine HI-S), I may give it a try.:)
 
Spectrapure manifolds two membranes together to achieve higher flows like I mentioned. Some other vendors make what I consider to be false claims on production rates by using inflated pressure numbers which are not achievable in most home use situations without a booster pump. They also boast 99% rejection and other things that are very different than the membrane manufacturer publishes.
I steer clear of un proven and ridiculous claims and stay with well known vendors and components like already mentioned.
And yes two membranes in parallel are additive, two in series are not.
 
<a href=showthread.php?s=&postid=6533646#post6533646 target=_blank>Originally posted</a> by AZDesertRat
Spectrapure manifolds two membranes together to achieve higher flows like I mentioned. Some other vendors make what I consider to be false claims on production rates by using inflated pressure numbers which are not achievable in most home use situations without a booster pump. They also boast 99% rejection and other things that are very different than the membrane manufacturer publishes.
I steer clear of un proven and ridiculous claims and stay with well known vendors and components like already mentioned.
And yes two membranes in parallel are additive, two in series are not.
Click to expand...

AZ, I do agree that most of the ratings fall short of what you will get in real water production every day, but this holds true for lower ratings as well. Bottom line, my unit produces quite enough water for me in an hour (more than the 100 GPD one I had previously), and it has read 0 TDS for quite some time.

Now I'm curious about the whole parallel series thing... not being facetious. Are there units that raise their rating by putting membranes in parallel? Wouldn't this be the same thing as just having 2 units running side by side? Never seen this before.
 
Thats how all large RO units are made. I am doing some consulting work for a municipality that has a 2 million gallon per day RO system that consists of 4 banks of membranes with 10 membranes in each bank. The membranes are 8" in diameter and about 10 or 12 feet long each. They are rated at 350 GPM per bank for a total of just a little over 2 MGD at peak efficiency.
All the units you see in Water and Ice and similar stores are the same type of configuration.
Look at the Merlin that Air Water & Ice sells, it is a great unit high production unit that uses multiple membranes in parallel.
 
<a href=showthread.php?s=&postid=6533850#post6533850 target=_blank>Originally posted</a> by AZDesertRat
Thats how all large RO units are made. I am doing some consulting work for a municipality that has a 2 million gallon per day RO system that consists of 4 banks of membranes with 10 membranes in each bank. The membranes are 8" in diameter and about 10 or 12 feet long each. They are rated at 350 GPM per bank for a total of just a little over 2 MGD at peak efficiency.
All the units you see in Water and Ice and similar stores are the same type of configuration.
Look at the Merlin that Air Water & Ice sells, it is a great unit high production unit that uses multiple membranes in parallel.
Click to expand...

Interesting... certainly makes sense for production on that scale. Link for Merlin? Do people within the reefing hobby use these types of units, do they look the same as the others?

EDIT: Found the link, I have seen these before in basements. Talk about out of my price range!
 
<a href=showthread.php?s=&postid=6534010#post6534010 target=_blank>Originally posted</a> by AZDesertRat
Sure makes a lot of water in a hurry though!
Click to expand...

But 2 grand extra for faster water doesn't make sense for a lot of hobbyists. Takes my unit less than half an hour to make 10 gal of pure TDS 0 H2O, so I always have some set aside for emergency changes. I'd rather spend the 2 grand on some more corals, or a new tank for that matter!

I just think we might lose sight of the point and make things needlessly complicated in this hobby. Whatever happened to KISS? Sure, I could spend a few hundred dollars on a colorimeter, and it would give me more precise readings than a standard Seachem pH test. But does every hobbyist who has an established tank *need* the extra two significant figures?
 
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