water softener and RO sufficient?

[Csalt]

I have a water softener and an RO unit for drinking water. Would this be enough or should I plumb in a DI? I've been lurking for a few months, just now starting to get things ready for a tank.

[AZDesertRat]

RO/DI is always the preferred choice since RO by itself only does 90-98% of the treatment. RO really acts as pretreatment for the DI which is what gives you 0 TDS, RO by itself cannot do this.

 

Before investing in an add on DI though I would do some investigating on the condition of what you have. Usually drinking water systems are not the same quality as reef systems and you may end up eating DI resin like crazy costing you a fortune.

What is your softened water TDS? What is your RO only TDS both from your drinking water faucet/pressure tank AND when you disconnect the tank and sample the TDS directly from the RO membrane itself? What is your calcium carbonate hardness before and after your water softener?

 

Take a look at this diagram, when you use a RO/DI for both pressurized RO drinking water and for reef RO/DI water you want to isolate the DI from the pressure tank so you do not suffere the effects of TDS creep:

http://spectrapure.com/huds/4-STAGE-DWK-RODI-NAG.pdf

 

Each time the RO cycles on and off to satisfy the presure in the small tank you get TDS creep which is hard on DI resin.

[jservedio]

I fully agree with AZDesertRat - invest in a handheld TDS meter so you can check the condition of your tap water and to see how well your drinking water system is working (you will need one of these anyway, so it isn't a waste of money at all). With that in hand, if you aren't confident that you are choosing the best system, give Spectrapure a call and tell them you are using it for a reef and they will hook you up.

 

Their customer support is great and will walk you through getting the best system for your needs - and they don't oversell you (at least in my experience with them). I ended up with a $180 system when they could have easily pushed me to a much higher end one!

[Csalt]

Ordered a HM TDS-3. Will post results after it arrives.

[Mr. Microscope]

Looks like you're headed in the right direction. to Nano-Reef!

[Csalt]

Well, I have 17ppm so i'm probably going to need to add a DI unit to it. I have a PC-4 RO system. Non RO water was 300ppm. RO water from membrane with pressure tank off is 16ppm (drips sooo slow.) I'll give specrapure a call and see what they say.

 

[AZDesertRat]

That means your RO rejection rate or removal efficiency is around 94.5%. Thats a little on the low side, it should be 96-98+% for good DI performance and lifespan. For every 2% you can improve that 94.5% you will double the life of your DI cartridge.

 

I would suggest keeping what you have for drinking water and investing in a better reef quality RO/DI for reef use or keep the autoshutoff valve, pressure tank and drinking water faucet and install them on a new reef quality RO/DI isolated by a check valve so you have the best of both RO drinking water and RO/DI aquarium water out of a single system.

 

A new RO membrane, flow restrictor, sediment filter, carbon block and DI cartridge for what you have now will cost you almost as much as the $125 a new reef quality RO/DI with a full size refillable 20 oz vertical DI and 90 GPD treated and batch tested high rejection rate RO membrane with an inline pressure gauge would cost from Spectrapure. I would also check locally with Buckeye Hydro, Russ is a great guy.

[Csalt]

Buckeye hydro is where I got the TDS meter from. Maybe I'll just tee off the supply line that goes to the ro unit i have now and add another ro/di unit for reef only. I'll call buckeye hydro and see what they say also.

 

Edit- Talked to a guy from Buckeye Hydro. Seemed helpful. May get an addon DI with bypass. This is my RO membrane. Never heard of the brand. Did some searching and all I could find are russian websites. Claims 96% rejection and is 50GPD.