RO/DI question....

[chefssaltyballs]

been looking at ro/di units from filter guyz melvels, bucks etc and i have come up with a question:
I dont want or need 75-100gpd I would be happy with 15gpd, 30, 40gpd etc..... my question is: if i get a system that produces less water per day will it have a better ratio of waste? I would happily trade production for waste saving???
my rarionale behind this is: (may be stupid but) if the water is passing thru the filter stages slower it will in turn filter better because it will spend more time interacting with the filter media. the down side, less water production.... the hopeful upside, less water in = less water out = less water wasted????

Oh and before you answer, I cannot afford a UHE system.... lol.... I am in the $100-$170 range...
i know i can get an ocean wave or a few other units for around that but i would prefer to get less gpd for my money if i can get a better ratio in its place????

anyone know if such a unit exists????
thx all
cfsb

 

[JAustin]

Go here http://www.purewaterclub.com/ and click on reef aquarium on the left side. There are many there but most are 100GPD. Several people I know have them and have been happy with them. There is a 50GPD on there for $62 bucks and they are all free shipping. You can go to Ebay and get an inline TDS meter for bout $20 and your all set.

This will be my next purchase.

 

[chefssaltyballs]

Cool, my question though, is will this unit have a better waste ratio? That is what I am looking for mainly. 50gpd is a fine trade off for less waste water? @ a 4/1 ratio I use 200g to make 50g with the more popular units. Will a slower unit filter slower therefor more efficiently, making less waste?
Cfsb

 

[chefssaltyballs]

to add further guys, I don't mind spending the $150 or so to get a decent system... There is a nice one on filterguyz for about $160 i am considering although $62 sounds great too, but i am looking to trade gpd for waste ratio but dont mind spending the same....
In a nutshell: if the 50gpd wastes the same as the 100gpd (meaning 4:1 ratio or so) then i would just get the 100gpd...
I am willing to spend about the same money to get less gpd if i can get better ratio....... I WOULD EVEN TAKE A 10-15GPD PRODUCTION IF I COULD GET 1:1

So far I have read that the flow restrictor determines the ratio ??? can someone please break this down for me?
am i reaching for the stars here guys ?
cfsb

Is this even possible

 

[JAustin]

You can go to google and look up differnt membranes but i think no matter what GPD the rejection rate is about the same. Maybe a 1% different.

A friend of mine has a filter guys RODI system and it's still making 0 TDS and it's a year old. He evaps a gallon a day and hasen't changed out a filter yet.

Make sure you have the proper water pressure....you'll lose efficency of the membrane if the water pressure is low....something like under 50PSI is not enough. If it's low you need to buy a boost pump...that adds another $60-80 to the cost of the RODI unit.

But yeah, they all reject about the same % no matter what the GPD. Your rejection % will depend on your water quallity.

http://www.watertreatmentguide.com/Membrane_Rejection.htm

 

[chefssaltyballs]

<a href=showthread.php?s=&postid=14534905#post14534905 target=_blank>Originally posted</a> by JAustin
You can go to google and look up differnt membranes but i think no matter what GPD the rejection rate is about the same. Maybe a 1% different.

A friend of mine has a filter guys RODI system and it's still making 0 TDS and it's a year old. He evaps a gallon a day and hasen't changed out a filter yet.

Make sure you have the proper water pressure....you'll lose efficency of the membrane if the water pressure is low....something like under 50PSI is not enough. If it's low you need to buy a boost pump...that adds another $60-80 to the cost of the RODI unit.

But yeah, they all reject about the same % no matter what the GPD. Your rejection % will depend on your water quallity.

http://www.watertreatmentguide.com/Membrane_Rejection.htm

JAustin
thx for the response... why is it that some people are getting 2:1 or 1:1 BY ADDING 2ND pumps and what not? If its all about rejection rate? more pressure should increase the gpd but shouldnt it decrease the output quality???? how are they getting 0 tds by adding additional pumps ??
I have spoken to may LFS in my area and most of them only use RO no DI systems... will using an RO only setup increase the ratio???? out of the five stores in my immediate area, only one uses an RODI setup the rest strictly RO...... ????

 

[maypo59]

I don't know about a set ratio for rejection, I belive it is all driven by the quality, or lack there of, of the input water. Adding a pressure pump to a system that is not performing well would help, if the problem was pressure in the first place. It won't make it pass more water, just bring it up to specs. To make more GPD you need a larger membrane.... more area exposed to inflow, so more area to pass water through.

I like a high GPD system because it makes water faster, I have less time to forget I am making water and flood the basement.. I used to run a 25gpd membrane, and when it came time to replace it, I went with a 75GPD and it made a huge difference. I don't think I am using any more water then I did with the smaller membrane, and now I can top off the holding tank (50 gallons) in about 3-4 hours. My water is pretty hard, around 370ppm coming from the tap, around 65 coming out of the RO and DI takes it down to 0.. I have about 60 psi of water pressure.

 

[chefssaltyballs]

Maypo,
I do not care about gpd !! I only want a better ratio....
say 1 gallon produced to 2 gallons wasted...... I am ok with 15gpd as long as the 15gpd made only creates 15-30gpd waste.. That is what I am trying to determine.. I dont have a pressure problem... I just want to know if i can get a sytem that has a better ratio, even if it means less GPD..???
thx man
cfsb

 

[maypo59]

Actually, I think the higher GPD units waste less water.. based solely on my experience in my setup. ALL RO/DI's waste water, none is anywheres near 2 to 1 ratio. If you want the least wastefull way to prepare water consider one of the chemipure units.

 

[chefssaltyballs]

<a href=showthread.php?s=&postid=14537387#post14537387 target=_blank>Originally posted</a> by maypo59
Actually, I think the higher GPD units waste less water.. based solely on my experience in my setup. ALL RO/DI's waste water, none is anywheres near 2 to 1 ratio. If you want the least wastefull way to prepare water consider one of the chemipure units.

Maypo,
I have to say i am very disappointed to hear that.... sighhhhh....... but I thank you for the information.... I know 2:1 and 1:1 systems exist that produce 75-150gpd but the are quite pricey..... like the UHE setup for example....I was hoping that there would be a less expensive version that had less production... Oh well, looks lke I will be ordering the
199.00 - OCEAN REEF + 1 FIVE STAGE 75 GPD RO/DI
from filterguys.. I just hate to waste so much water... I will have to come up with a way to use the waste water, or at least some of it......Somehow ?????
damn
cfsb