RODI or Kold Ster-il?

[cubber]

I am looking into a water purification system, and trying to decide what is the better option for me between RODI or Kold Ster-il. I do have an abundance of sand in my water at times and even with a sediment filter on the line it still tends to get through or clogs the sediment filter up fast. Currently I use a python to fill up my rubbermaid brute can for water changes. In the end of the python I stick a filter sponge, then a bag of black magic carbon, then a polyfilter and finally a 50 micron filter pad at the end. I run the water through this slowly and this keeps all the sand from getting into my mix water and also helps to remove any pollutants and odors that may be present in the water. My tanks have done great using this method for the past 3 years at this location. My tap water is very clean and I never have any readings of ammonia, nitrite, nitrate, or phospate from my test kits when testing straight from the tap. The PH of my water is always around 8.2 and the hardness is usually around 7 or 8. I am wondering if I went with an RODI unit if I would have troubles with it from sand getting through the stages and into the RO membrane. I am leaning towards the Kold Ster-il unit because my tap water already obviously has good buffering capacity as well as minerals and elements that are essential to a reef system.

[pjf]

I've had a Kold Ster-il unit for the past two years and I am very happy with it. I use the regular stock media but additional media and stages are available if needed.

I've had two issues with my unit. The phosphate level was high initially due to the phosphoric acid used to activate carbon media but the level quickly dropped to zero and has stayed there. My tap water has silicates that are not filtered by the Kold Ster-il unit. Diatom blooms occurred regularly until I replaced my Remora protein skimmer with a Tunze 9010. By keeping other water quality parameters at the proper levels, silicates are not a problem.

Because tap water contents vary across the country, initially you may have to perform more water quality tests. Perhaps different media or additional filtration stages may be needed.

Unless I am running a laboratory, filtered tap water is satisfactory for me. I agree that the Kold Ster-il unit may not work at all locales or aquariums but it does conserve water and is very convenient to use.

[E-A-G-L-E-S]

either will work, but kold ster-il is much more expensive...i'd get an RO/DI and never look back.
-jmo

[cubber]

Thanks for the input, my main concern is the abundance of fine sand particles in my water. It looks like the Kold Ster-il unit will be better suited to handle this than an RODI unit. Has anyone had any luck running an RODI unit under heavy sediment conditions? I thought that this will drastically shorten the life of the RO membrane.

[E-A-G-L-E-S]

It would do just that....a second sediment cartridge would help a little.
Kold Ster-il is a great unit and doesn't create the waste water an RO/DI does.
If K.S. will work better for you then get that, if not then go the less expensive route....it's up to you and either will work.

My city water is very hard....which exhausts my sediment fairly quickly... ~150g made

[cubber]

Thanks E-A-G-L-E-S. I have a whole house filter which is basically a micron filter cartage but the sediment quickly clogs it up within 5 days of use and much of it still passes through it. I find myself actually running it on bypass because it has been pretty costly not to mention a PITA to change the cartages on it every 5 days.

[David Grigor]

Kold Ster-il is best suited for well water. There is a certain metal that if present in your tap water will riun the unit. I forget exactly what that was since it has been many years since the topic has come up. Something with aluminum in the name.

Anyway, a local reefer in our club got on before researching the local municipal water content and fouled the unit very quickly. They wouldn't refund or return because they said he should have checked/researched first. He ended up selling it to someone with well water where it is a non-issue.

So do your homework before getting one......

[David Grigor]

ooops. duplicate post.

[David Grigor]

I found it. This thread:

http://archive.reefcentral.com/forum...ght=Koldsteril


Posted by Agu on 12/15/2000 09:27 AM:

Kold Sterile is designed to produce quality tap water, not pure water for a reef. The pH and alkalinity will be higher than ro/di water which can be a good thing, maybe.

The optional alumina adsorber does remove silicates and phosphates but you'll have to slow the flow to a max of two liters/min. If your water has high levels of these compounds the flow rate has to be even less.

Poly-bio-marine does not guarantee their product, except if it's broken in transit or defective. Check their guarantee on their website !!!! 30 days, manufacturing defects only!!!

Before buying their product check your water parameters at http://www.waterdata.com , forward this info to poly-bio, and ask if their product will work with your source water without further water treatment.Ask for a suitability guarantee in writing!!!

If it will work for your application, I have a unit available for $175, needs all new media(about $40). It won't work with my source water unless I'm willing to add muriatic acid to the resultant water to lower pH. (and start buying the alumina adsorber in bulk)

Poly-bio does not dispute that their product does not work in my application without using vast quantities of adsorber and adding muriatic acid to the final product, but four requests asking them to take it back have been ignored.

Kold Ster-il for sale !!!! I'm serious, 2 months old, needs new media.

Agu

[cubber]

Thanks, I will have to look into that. The only way for me to tell if my well water contains that is to test for it. Anyone know where I can obtain a test kit for alumina?

[David Grigor]

Doubtful there is a problem if using for well water. It municipal tap water that may add something to the water to help precipitate metals that causes the filters to exhaust quickly.

[AZDesertRat]

Spectrapure offers a new pleated prefilter with 10x the surface area of a normal prefilter, thus less prone to plugging. They actually beta tested this filter for a long time in New York state to ensure it would work well before introducing it to the market. I would highly recommend a 150GPD MaxCap RO/DI system with this new prefilter.

If you are on a domestic well and do not have a current water quality report you really should do so ASAP. It is recommended you do a well scan or lab analysis for the most common elements at least every 5 years if not more often in some areas. Here in AZ it runs about $150 for a pretty complete report .

[pjf]

Originally posted by cubber
Thanks, I will have to look into that. The only way for me to tell if my well water contains that is to test for it. Anyone know where I can obtain a test kit for alumina?

The alumina media removes silicates and additional phosphates. You would test for silicates and phosphates before deciding to purchase the alumina media.

[AZDesertRat]

Alumina media has a pretty short lifespan and releases contaminants back into the treated water when it is exhausted. You would need to do frequent testing after the media to ensure it has not reached it capacity. Granular ferric oxode or hydroxide medias do not release contaminants but bind them.

[pjf]

Originally posted by AZDesertRat
Granular ferric oxode or hydroxide medias do not release contaminants but bind them.

Are these materials effective for both silicate and phosphate removal?

[AZDesertRat]

Yes along with arsenic and several others. It has been used extensively in drinking water treatment for years and is just now being recognized as useful to the reef hobby.

[REEFGREENER]

P.M. Sent

[cubber]

Thanks for all the info. I will do some further research before I decide which unit to go with. I also will look into getting my water tested.

[pjf]

Here's the response from Poly Bio Marine regarding my query about using ferric oxides or hydroxides instead of alumina for phosphate and silicate filtration:

"For potable water only ferric hydroxide is used for phosphate and silicate adsorption.
Ferric oxide is not used for potable water single pass adsorption of phosphates and
silicates.

We use , food grade , activated alumina that is specially prepared for potable water
filtration then we further leach it in sterile, ultra pure water. The activated alumina
is preferred since it is white and doesn't release any impurities or heavy metals.
Our grade of activated alumina is a charged , porous ceramic it not aluminum
oxide that is sold into the pet industry as activated alumina. We use only the
food grade product approved for potable water and then further process it and
leach it to remove any excess heavy metals or leachables.
The ferric hydroxide is not manufactured in the USA and will release hydroxides
into the filtrate. Further, we can place the activated alumina into the second stage
0.20 micron filter bag for phosphate adsorption. Silicates require an extra canister
filled with two pounds of activated alumina placed after the Kold Ster-il (r) system.
Why is it placed post Kold Ster-il (r) System ? For either activated alumina or
ferric hydroxide to function either media must have water at a 7.5 pH or higher.
Silicates require alkaline pH for adsorption.

If you want to try the ferric hydroxide you will need to purchase a additional canister
and a media retainer capable of holding one - two pounds of the medium. Keep the
water flow rate at 0.50 liter per minute for maximum contact time.
Note : You need to be aware that certain areas of California have very high levels of
silicate that may require more than one treatment to adsorb all the silicates. Actually
you might consider filtering the tapwater then collecting it and placing it into a closed
re circulating loop that slowly passes it through (0.50 - 1.00 liter per minute per 2 lbs of
medium) either the activated alumina or ferric hydroxide .

Recently we have been requested by several pollution control companies to produce
a Poly-Filter (r) with added ferric hydroxide . We may be offering this product in a
disc form within several months. Since we would manufacture the product we can
purchase ANSI / NSF approved Ferric hydroxide which we would add to our Poly-
Filter (r) allowing us to offer a far superior product to ferric hydroxide granules."