Softwater with RO system, Do I need DI?

[alohaeveryone]

Hi Everyone,

 

I used to buy RO/DI water from local fish store when I need to fill the tank from evaporation. I just move in to a new house and starting a new 60 gallon tank. I scheduled an appointment to install a Softwater + Drinking Water system coming Sunday. I am assuming the Drinking Water System is RO. My question as following.

 

Is Softwater safe for reef tank after pass though the Drinking Water system?

 

Do I really need DI filter? How do I find out? I have a water testing device read something like "ppm" does it has to read "0" or I can take a chance even it doesn't.

 

 

If I have to get DI Filter, any suggestion I can get that ship to CA before Sunday so I can have the installer do it for me at the same time?

 

 

 

Thanks in advance.

[Rocket]

After an RO unit yes. I am on softened water. What it is actually is water that was filtered by ion exchange with salt. The water has elevated salt levels, although I can't taste the difference some of my friends on city water can taste a hint of salt.

 

Depending on where you are located the DI resin can be depleted rapidly due to ground water with high concentrations of Carbon Dioxide. ( I also have this problem) I Only run DI on the water changes, RO works just fine for top offs, and when I run out of DI resin I'm going to try just RO.

 

Well with "drinking water systems" you are going to pay a lot for something you can easily do your self. I'm talking filter replacements. My water guys charged me $435 couple years ago to replace all the filters in a 5 stage unit. I learned from here it is easy. Now filters cost me about 40 a year.

 

To add the DI, this worked fine for me, Just splice it in after all the filter stages, it must be the last filter in the line. DI filter

 

 

One last thing. You may need a Y and a valve to bypass the carbon taste filter that many of these RO water drinking systems have. It re-mineralization the water for taste, but this is not ideal water quality to add to a reef tank.

 

Again, use the above link, they are a sponsor and all RO/DI supplies you could need are provided at reasonable-cheap, prices. I even bought 100ft of line to run the water straight to the tank. Be creative, will save you time, and your back.

[alohaeveryone]

Thanks Rocket.

You got all the info. I need.

[AZDesertRat]

RO membranes love softened water, in fact all major manufacturers recommend using soft water and will not warranty a membrane if it is not on a softener.

 

Yes, you do need DI. The RO acts as pretreatment for the DI and by itself is only 90 to 98% effective at removing contaminants. RO by itself is not particularly effective at removing some things like phosphates, silicates and nitrates so it takes the combination of carbon, RO and DI to work well.

 

Anything other than 0 TDS is not acceptable since TDS is not a measure of anything in particular so you have no idea what that TDS is made up of only that something electrically conductive is present.

 

Yes carbon dioxide shortens DI life but that can be remedied easy enough or there are resins blended specificaly for high CO2 waters. I have high CO2 and I get over 1000 gallons per 20 oz DI cartridge so it is possible. I would never use RO only when RO/DI is so inexpensive and readily available.

 

Before you have a contractor install the RO you might look at doing it youself, you will get a much better reef quality system and probably for hundreds less. I looked at a system earlier today that retailed for $689 plus installation that was no where near reef quality which would only cost $145 plus a $63 drinking water kit and take maybe 30 minutes to do yourself. RO installation companies take you to the cleaners and give you a low end drinking water system which is very different from a reef system.

[Rocket]

We meet again Mr rat. Please elaborate on the CO2 resins.

 

As much as I could find expensive co2 remover or a aeration tank and then re-pressurize the water. I have about 4-16 TDS after the Membrane and still deplete a DI cartridge in 60 gallons.

 

I'm going to try the spectrapure membrane come December.

[AZDesertRat]

Take a look down close to the bottom of the page here at the DI-SF-CC-10.

I'm not using it myself because my MaxCap has been performing so well but I have heard good things about it. You might try contacting Spectrapure and discuss your problems with them, they love a challenge and might be able to work with you on a solution.

[alohaeveryone]

Thanks everyone for the advice.

[Hans Dorn]

We meet again Mr rat. Please elaborate on the CO2 resins.

 

As much as I could find expensive co2 remover or a aeration tank and then re-pressurize the water. I have about 4-16 TDS after the Membrane and still deplete a DI cartridge in 60 gallons.

 

I'm going to try the spectrapure membrane come December.

The DI stage doesn't need any pressure, just flow.

My RO doesn't have a DI stage, so I got me a separate DI filter. I just fill a bin with RO and then use a powerhead to cycle the water through the DI for a while. About 1h should do the trick

 

You could try the same and maybe aerate the RO for a while beforehand.