High capacity RODI?

[Armando]

Starting to plan my upgrade to 220ish.

First thing I want to resolve is the slowness of the RODI. Currently I have a 100GPD Oceanus equipment but for me it's really slow. I also started using RODI for my orchids recently, so I need higher capacity.

I did a quick search but didn't find a lot of RODIs above 200GPD. Would like to hear from the big-tank people what is recommended, as far as GPD and brands.

TIA.

[Bebo77]

airwaterice makes them larger.. whole house systems if need be....

[kwl1763]

Try a GE Merlin. (available at airwaterice) Makes up to 700GPD. I'm using one and really do get ~500 with no booster. Really nice when you have a ton of water!

[Mind_nl]

If you want high capacity check out Bill Wann's 3200 gallon/day setup: http://archive.reefcentral.com/forum...5&pagenumber=2

[Armando]

I'm looking at the Merlin at the airwaterice. Seems good but it's RO, not RODI.

[moonpod]

there's an add on Double DI. Also you can get an optional double pre carbon filter which will extend the life of your merlin membranes. That's what I'm using and it's amazing really.

[sfsuphysics]

you could also ditch the RO part of the system and go with a cation/anion system and just recharge your resins as needed, then you'll get some quick water, and without any of the waste water issues

[tacocat]

Armando, why are you using RO/DI for orchids? Most plants could use the extra minerals, etc found in muni water. My father-in-law grows orchids in his greenhouse and he uses muni water.

Is there an added benefit using RO/DI?

Oh yeah, here are some pics of moonpod's Merlin. I stole them from Garrick's thread.
http://archive.reefcentral.com/forum...5&pagenumber=2

[asnatlas]

Originally posted by tacocat
I stole them from Garrick's thread.

Thief

[kwl1763]

Mine is setup much the same, standard set of prefilters with an add on DI after. Works great!

[Ixthys]

RO is the rate-limiting step in RO/DI water production, right? And from what I can tell, the Merlin only has 1 RO membrane. So how does it overcome the speed issue? Or does it just put out a higher TDS and let the DI resins do the rest?

Thanks for any info.

[moonpod]

Its a dual RO setup (the basic unit is 1 carbon prefilter and 2 RO membranes--I use an addon dual carbon prefilter and a dual DI addon) the membranes are not standard Dow membranes. They are different

[Johnsteph10]

Chuck,

How do you like it? I'm considering it as I'm sick of waiting to make water all the time.

You got: add-on dual carbon prefilter, then the merlin, then the add-on dual DI. Anything else you would need?

[moonpod]

Yeah that's the setup. I like it quite a bit

[Ixthys]

I take it your TDS is 0.

[moonpod]

probably not. I haven't checked the filters in A LONG time....

[Ixthys]

The website pdf file says it is a carbon pre, RO unit, and carbon post. Am I looking at the wrong thing, 'cause I don't see one with 2 RO units.

[edit]..well then I go and pull up the instruction manual and it shows 2 RO's...

[kwl1763]

Ya it's a pre and 2 RO membranes.

Honestly you are correct the RO is the rate limiter so putting standard fiters in front (I use 3 1 cocunut, one micron, one carbon block) then an add on DI on the back. I just use the coralife add on.

I get zero TDS and the DI lasts a long time. Going in to the DI it's less then 10 normally and my tap is at 272!

I've been running it this way for 6 months and no issues!

[toothman]

am I right in seeing on the spec. sheet that it will make 750 gal a day,(great) of about 140 ppm pure water. (from 1600 ppm water, example of Fla. water) I was not aware that ro had that high of a particle content. Does this unit produce less pure water than kent units. I do have di after but was not aware that the di had to remove that much to get less than 5ppm or so.

Long story short, is it alot of half pure water?

[AZDesertRat]

When you get to "high output" or "high capacity" membranes instead of "high rejection" membranes you lose efficiency. That is exactly why the Dow Filmtec 75 GPD high rejection is 98% and the Dow Filmtec 100 GPD high output is 90% rejection.
Personally before I would go to a high capacity system I would manifold 2- 75 GPD membranes with a dual DI and a booster pump. This should give you all the high quality water you would need in a 24 hr period as long as you have some storage capacity.
You are not going to find a high capacity membrane that is better than 90% rejection.

[moonpod]

1600 is absolutely foul water and a resultant 140 afgter a pass through the Ro is better than 90% rejection

[toothman]

My tap is well water, it has 600 ppm and runs through my 65gpd kent ro di plus a extra di, it usually comes out with less than 5ppm when done with a absolute new cartridge in one it is close to 0. I like this method but more water quicker sounded nice but too much ppm for me.

[AZDesertRat]

You should be getting better water than that. My raw water Saturday was 627, after RO only it was 11 and after a single vertical 24 oz refillable DI with almost 200 gallons of usage on it it is still 0. I will admit its just about time to change the resin, I usually get 200 to 2500 gallons per 24 oz refill before I see it creep up to between 2 and 3 which is my trigger point. My membrane is 2 years old and has seen lots of use between drinking water, ice maker, pet water and aquariums.

[moonpod]

toothman, even with a 90% extraction membrane you should be below 60 out of the RO membrane and 0 with a DI. A 98% should give numbers like what AZ rat is giving. The number one factor for protecting your membrane is limited chloring exposure to the membrane.

For most people, I agree that a dual 75 gpd unit is probably the best way to go.

What is impressive about the Merlin is that it really still works well at relatively low pressures obviating the need for a pump to optimize the performance.

[Ixthys]

If I added the Merlin in place of my RO, would I get the same high volume production with zero TDS?

Currently I have a Spectrapure setup with:
Sediment
Carbon
RO
DI #1
DI #2

My TDS in is 170 and zero out