what size RO/DI unit?

kniquy

Member
I am in the market to purchase a ro/di unit for my top off and saltwater mix. I see that there are various units out there from 3 stage to up to 7 stage. The water in my town is actually really good (I work at a dialysis unit and they send the water to a lab to test -- the results are almost near perfect). I am looking at a 4 stage ro/di unit -- would this be sufficient filtering for my reef tank?
 

sweatervest13

Active Member
Are you using it also for water changes, or just top off's??
4 stage is not too bad and should work just fine. But sometimes units can come with some nice extras like a TDS meter, or a flush kit. Check out BRS 5 stage plus kit. It has a lot of nice extras. You will pay a little more, but IMHO it's worth it.
A city's water source however good is still pretty high in TDS compared to an RO/DI unit. You should be getting 0 TDS from a good RO/DI unit. A great city water TDS is 200-100 TDS. But the better water source the longer the filters should last in your unit!!! So, Score!!
 

2quills

Well-Known Member
Yep check out the BRS units. I just picked up a 6 stage with all the goodies that sweatervest mentioned for less than the cost of most 4 stage units out there. Filters and media can always be upgraded down the road. Good bang for your buck to get started IMO. And they use metal brackets now, not the cheap plastic.
 

kniquy

Member
I am going to use it for my water changes on my 75g. Are all filter media standard for all water filters? or are there different sizes for different gal per day units. What sorts of upgrades can be made? would that just entail changing out the types of filters?
 

bang guy

Moderator
They are not all standard but there are two sizes that are most common. As far as GPD most of the time the different speeds are the same size but after swapping out for a new speed you also need to change out the flow restrictor.
 

2quills

Well-Known Member
Quote:
Originally Posted by kniquy http:///t/395965/what-size-ro-di-unit#post_3526879
I am going to use it for my water changes on my 75g. Are all filter media standard for all water filters? or are there different sizes for different gal per day units. What sorts of upgrades can be made? would that just entail changing out the types of filters?
Yep, different brands of cartridges, media and membranes can be found for the different brands of units. The main reason I chose to go with a BRS unit is because they have a lot of options to pick and chose from. Anything from gauges measuring water pressure, to inline TDS meters, automatic shut off valves, flush kits, pumps to help boost efficiency etc. BRS gives you the option to pretty much build a unit specific to what ever you want. So you can start small and add on later if you ever feel like it's necessary.
Different situations might call for different methods of filtering. If your city happens to use chloramines (carbon does not remove) in the water then you may opt to run a chloramine removing cartridge. If you have well water with a lot of sediment you may opt to run multiple sediment cartridges, etc. Well water used to be considered good water to have. But now a days in a lot of places well water is becoming toxic from all of the oil drilling/fracking for natural gas that is about to spread like the plague all over this country for the next 100 years. Folks really should know what's in their water these days.
Personally, our city has pretty hard water and can be a touch high in phosphates. I'm going to run dual carbon and DI cartridges along with the sediment filter and membrane.
 
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