Best Reverse Osmosis RO DI Aquarium Water Filter

[reefGod]

Hi,

I am quite new to Salt water aquariums, but from the information i have gathered so far, when doing water changes or compesating for evaporation, it is quite clear that normal tap water absolutely does not do and an RO/DI unit is needed! So what i would like to know is, what are the best products out there? I have noticed many different (new) models being sold on an auction site , i dont want to regret my purchase, so i though y'all could fill me in...

thanks
mat

PS.: Id also like to know what i should do meanwhile until i get one of these units, should i buy distilled water???

thx

 

[borntoexplore]

I've gone for a year using well water because I can't find any third party reviews of the competing reverse-osmosis systems. I can find info on what type of filter to get, but nothing as to which manufacturers are reliable & cost effective. All I can find is info from the vendors themselves, which I certainly don't trust. And funds are very limited, so I want the best deal I can get for a reliable system. Our water is high in iron, manganese, & sulfur. Don't know how bad that is for reefs - I've got good coralline algae growth, and I've had some easy soft corals surviving (but not spreading) for the last six month. Haven't tried anything more difficult. Too much algae growth, also. Water pressure 40 psi, lead ND<0.005, copper ND<0.014, iron 0.35, manganese 0.17,nitrate ND<1.0, phosphate ND<0.2. Probably some silica. From what I understand I don't need a carbon unit, but I do need backflushing capability because the iron bacteria will clog up the system, and maybe a second sediment filter.

 

[ChrisRD]

Hi and :welcome:

It's possible to use tapwater (although I don't recommend it), however, the quality varies significantly from place to place (and even from the same well or public water system) so many reefers use some sort of purified source water to help minimize the introduction of excess nutrients and pollutants into their systems. RO/DI units are very popular because they are generally the cheapest way to go in the long term (despite the initial investment required).

A couple of places that sell RO/DI units and supplies that I've heard good things about (I own a unit from ARS - they've been great to deal with):
http://www.aquaticreefsystems.com/
http://www.airwaterice.com/
http://www.buckeyefieldsupply.com/

Any of the regular brand names like Kent, Spectrapure, etc. are fine as well.

HTH

 

[SnowManSnow]

I bought my 75gpd unit from Buckeye, like posted above, and it has been great. Takes my TDS from 57 to 0.

For the price, with obvious good results, it's hard to beat them.

B

 

[borntoexplore]

Thanks for the help! I finally took the plunge and ordered a system. I'm justifying my purchase by getting an undersink drinking water system (wink, wink) so our water tastes better. Maybe the well water was OK, but it added a level of uncertainty and it's not possible to test for every possible contaminant in water, so what the heck.

 

[owenz]

I have a question: what's the best test or series of tests to run in order to figure out if your RO filter needs changing?

 

[ChrisRD]

I'm assuming by RO filter you mean the membrane.

Measure the TDS of your source water and measure the TDS on the output line of the membrane. Calculate the rejection rate based on those two readings. If the membrane is performing well (ie. acceptable rejection rate) it's still working fine. They actually make dual in-line TDS meters for this very purpose (ie. monitoring membrane performance).

Example of calculating rejection rate:
Say you measure your incoming water at a TDS of 250. Say the water after the RO is giving a TDS reading of 10. Your rejection rate is:
250 - 10 = 240
240 / 250 = 0.96 or 96%

Example of a dual in-line TDS meter:
http://www.marinedepot.com/md_viewItem.asp?idproduct=RO1312

HTH

 

[Anonymous]

I do not know if it the best, but I got the Air water ice typhoon filter. Have yet to set it up.

 

[intensity888]

If the rejection rate is 93.3 % before DI is this sufficient? After DI supposedly rate goes up to 99% on the unit i'm looking at.

 

[ChrisRD]

Sounds like it's working pretty well (depending on brand/model). The membranes normally used in the hobby are generally rated from 90% to 98% but you may not achieve the rated value due to variables like water temps/pressures and what's in the input water.