RO/DI vs. Kold-Steril

[morgan1965]

I'm setting up a 550 gallon reef system with auto topoff. I pay for my water so I'm trying to minimize the waste associated with RO/DI.

I've heard of Kold Steril units which eliminate waste water. Can they be set up to operate with auto topoff units the same way RO/DI units are set up? Anyone have experience with both RO/DI and Kold Steril who can give a comparison?

If I go with RO/DI, I'm thinking AWI Typhoon III. I've read about using two RO membranes in series to cut waste water in half. Does this work?

Beyond the two RO membrane idea, I figure my best bet is to ensure correct pressure and temperature. For pressure, I expect to use a booster pump if necessary. For tempreature, I've read about running the source water through several feet of tubing in a five gallon bucket of heated water to give the RO/DI unit tap water at 77 degrees. Since my system will have a 150 gallon sump full of 77 degree water, I'm thinking of putting the extra tubing in the sump. My questions: How much tubing should I use? What about heat transfer? Is there special tubing that will allow the water in the tube to heat up faster? Has anyone actually done this and seen it make a difference?

[morgan1965]

Anyone...anyone
I can't believe it, an RO/DI question and no one has anything to say. Would it help if I said that I was planning on buying one of those cheapy ebay units?

[Tomzpc]

The Kold-Steril is not very effective as a water purifier for the reefkeeping hobby in my experience. Call Walter at AWI, especially since you're already looking at their system. He's a real nice guy and he'll guide you towards the right setup.

[smleee]

It sounds like you've done some research and know what characteristics to get in an RO/DI unit. Since you're setup is quite large that may be the reason for lack of response. I have read about the "dual-membrane" method (although I thought it was a parallel setup used to produce water faster) and it seems to work well for high demand systems. It is usually better going with 2 - 75GPD membranes than 1 - 100GPD membrane and burning up DI. As far as the tubing goes, ~25ft coiled in the sump should do the trick.

eee

[BeanAnimal]

You can cascasde several 100 GPD membranes to reduce your waste water ouput to almost 0 (4 membranes if I remember correctly) and still get 0 TDS. This however will reduce the operating pressure so you will need a booster and possibley permeate pump.

Bean

[KMDO]

Im looking into this right now for purchase and wondered the same things.

What exactly would make the Kold steril unsuitable for reef water?

From their website it seems to say the water is better suited to reef animals than an RO/DI. Id rather get the RO/DI Myself as it is noteably cheaper by about 140 dollars but a lot more to expensive to run since filter changes are a lot less on the poly bio set up and there is no waste water.

From their site
"The Kold Ster-il® uses three separate stages to sorb heavy metals, VOC's, TOC's, Total Phosphates, fungus, algae, diatoms, particulates, Giardia, Cryptosporidium, bacteria, endotoxins, pyrogens, biopolymers, charged water conditioning polymers, Chlorine, Odor, Taste, VOC's, Pesticides/Insecticides, particulates, Giardia, Cryptosporidium, heavy metals to meet U.S.A., Canada, E.E.C., Japan Standards. The Kold Ster-il® doesn't remove calcium, magnesium divalent cations nor strip the water's alkaline reserve. People, animals, reptiles, birds, marinefish & invertebrates and African Cichlids benefit from very high quality water with the minerals and buffering capacity remaining in the filtrate. In addition, our Kold Ster-il's filtrate meets or exceeds ANSI/NSF Potable Water & FDA Bottled Water Quality Standards. Actually, our Kold Ster-il® has passed the more stringent Japanese Water Quality Standards and is certified to produce 14.0 liters per minute of potable water for usage in Japan"

[hottuna]

why not use both and get optimal results with no waste water? run the waste water hose of the r/o to the input of the kold steril...i have tried it ...it works.. u get de mineralized water form the r/o and mineralized water minus impurities from the kold steril...a win- win situation...

[KMDO]

That would work:D

[morgan1965]

Okay, I've decided agianst the Kold-Steril unit in favor of an AWI Typhoon combined with a Spectrapure Pass to Drain kit (Configuration #5). Here's my basic idea:

1. 25-50' of tubing in sump to warm the input water to 77 degrees
2. booster pump, if necessary
3. 10 micron sediment filter
4. 5 micron carbon filter
5. 1 micron carbon filter
6. Spectrapure Pass to Drain as a controlling unit with auto bypass remote vsalve, pass to drain remote valve, and pressure switch on ouput line
7. three RO membranes in series
8. product water split: one through kalk reactor to topoff (controlled by solenoid mounted in sump) and the other to a 90 gallon open storage tank for water changes (controlled by float valve)


Questions:
1. I want to be able to monitor the function of each part of the system. Where should I locate TDS meters and pressure gauges?


2. I've seen a surge tank used in the product water line for discharge pressure management. How does this work and why is it needed?

3. BeanAnimal: Why use 100 GPD membranes? Everything I've read says use the 75s. I gather it has something to do with the fact that there are multiple membranes and they're in series?
BTW, I see you're in Pgh. I went to college there. I'll never forget boarding an airplane in Sacramento with temps close to 110 and looking forward to landing in Pgh where it was only 96. No one mentioned the 100% humidity!! My first college lesson: it really isn't the heat ...