RODI from Well Water Question

Jongalt26 · Dec 17, 2016

Next month Im moving to house that has well water and a septic system.

The well water passes through a water softening system. I'm thinking that placing my RODI after the water is softened will help preserve membrane life and DI Resin. Does anyone know if there are any issues with this?

Also, it would make my life a lot easier to plumb my fishroom utility sink to the sanitary system. I've read conflicting reports on the following: Does anyone have any experience running saltwater through the septic system? (no more than 40 gallons per week, and most likely half that)

Thanks
Jason

Mr_Banana_Pants · Dec 17, 2016

I can't comment on salt water in the septic system. I have a well and septic so I just dump the water outside, just Crack the door for 5 mins.

As for as well water it is above and beyond most municipal systems. I've run probably 1000 gallons through my ro/di system and haven't seen any di usage. I'm at 0 tds going into the di... I don't have a softener on the system so I have high alkalinity, even when I use fish only salt so your ahead of the game there.

Tink · Dec 17, 2016

I have well and septic also but my problem is very low pH. Have you checked yours? Perhaps prior to the softener as well? Low pH is generally an indicator of high CO2 levels in your water and while it won't bother your RO at all it WILL deplete your DI resin like crazy. If this is also your case I can only recommend that you do like myself and make RO water into a container and aerate for 24hours minimum before pushing it through your DI. As for the softener I'm not 100% sure what to suggest. I do run my unit with water prior to my treatment, but I'm also using a sodium hydroxide injection to raise pH and not salt. I only do it to save from wasting chemicals.

I wouldn't sweat putting that little saltwater down the drain. What I do is turn on the utility sink while I dump it and then leave it run a minute. Figure if you take a shower that right there will dilute your saltwater pretty quickly. I have my septic pumped every 2-3 years and have not had any trouble.

Now here is the BEST thing you can buy if you're on well water and want to make your own RO water:

Pentair GRO-75EN membrane

It's a true 1:1 ratio membrane and it actually works. The rejection rating for me with my cold low pH well water is still 95% and it saves a ton of water. Make sure you use the recommended flow restrictor and have either the proper psi or a booster pump to get you there. Totally worth it.

Lowstorm · Dec 17, 2016

I have both too. I just dump my 10 gallons of water in the toilet when I'm doing a water change. I have high iron and tds going into my rodi, but haven't needed to replace anything since it all gets stuck in my first filter. No softener system.

I'd run the rodi before the softner, see how it goes. I remember reading somewhere that softeners can do a number on rodi but don't remember where.

Elementalj · Dec 17, 2016

Lowstorm said:
I have both too. I just dump my 10 gallons of water in the toilet when I'm doing a water change. I have high iron and tds going into my rodi, but haven't needed to replace anything since it all gets stuck in my first filter. No softener system.

I'd run the rodi before the softner, see how it goes. I remember reading somewhere that softeners can do a number on rodi but don't remember where.

I would not. Sorry to disagree but you'd rather there be sodium ions hitting the membrane than magnesium and calcium. You'll end up with limestone and/or gypsum clogging the membranes up.

Lowstorm · Dec 17, 2016

I don't mind disagreeing like I said, I have no softener, so in my house at least it makes no difference.

Jongalt26 · Dec 17, 2016

Thanks a lot for the replies! I havent checked the PH on the new house yet, i'll snag a water sample at the presale walkthough. Hopefully i can get a sample before and after the softener. I already burn through resin at my current house. I run dual resin canisters and typically have to replace both before 150 gallons. I think mainly because my water pressure is crazy high here (a bit over 100 psi). Tink, how do you push it through your DI after the aeration? Is there a decent pump for the 1/4" fitting?

Thats great news on the septic, i think im just going to plumb my sink to the sanitary line then which will make my life easier.

Thanks for the membrane suggestion, i have the two Dow 75's now. I'll snag the pentair when i need to replace them, which i'll most likely do when i move since i've had them for over a year.

Jason

Tink · Dec 17, 2016

I had tried a cheap eBay booster pump years ago that didn't do much so I use that to push the water through the DI now. Bought an 8800 after that and I would strongly suggest that booster pump if you need one.

Jongalt26 · Dec 17, 2016

Thanks, i picked up an 8800 already since i know the pressure is very low at the new house (heck i have to frack the well, replace the current pump and bladder tank etc etc)

JDJP · Dec 18, 2016

I don't dump my saltwater down the drain. Remember there is live bacteria in your septic tank that needs to be there to break down all that stuff.

I dont know for sure if its harmful, but i do know that getting your septic tank pumped or a new drain field gets very expensive.

I also have a well with no softener and make my own rodi. My di resin seems to get used up fairly quickly. I make it a point to flush my ro membrane for 5-10 minutes before and after i fill my brute.

DanConnor · Dec 18, 2016

I've dumped seawater into my leach field forever. It's quite diluted in the septic tank. Remember, urine is salty too and plenty of that goes down.
I do pump my septic tank every few years though, but I would do that if I was dumping saltwater or not.

Mr_Banana_Pants · Dec 18, 2016

Jongalt26 said:
Thanks a lot for the replies! I havent checked the PH on the new house yet, i'll snag a water sample at the presale walkthough. Hopefully i can get a sample before and after the softener. I already burn through resin at my current house. I run dual resin canisters and typically have to replace both before 150 gallons. I think mainly because my water pressure is crazy high here (a bit over 100 psi). Tink, how do you push it through your DI after the aeration? Is there a decent pump for the 1/4" fitting?

Thats great news on the septic, i think im just going to plumb my sink to the sanitary line then which will make my life easier.

Thanks for the membrane suggestion, i have the two Dow 75's now. I'll snag the pentair when i need to replace them, which i'll most likely do when i move since i've had them for over a year.

Jason

I would be extremely careful dumping saltwater down the drain. Adding saltwater to a fresh water septic system, I'd be worried about messing with the good bacteria that the septic relies on. It just makes me scared.

And as far as pH, aerating with a skimmer should help. And if you deal with high CO2 in the house a CO2 scrubbing filter works wonders.

cromag27 · Dec 18, 2016

The rodi goes AFTER the softener. you'll greatly improve the life of your membrane.

Jongalt26 · Dec 19, 2016

I think a lot for me is going to depend on which will be easier, going into the stormwater system or through the sanitary system. For the stormwater i'd have to drill a hole though the wall, add a fitting and hose to the downspout. For the sanitary system i'll have to see if i can find the pipe and see if i can get to it easily.
Thanks!
Jason

ihavecrabs · Aug 3, 2017

I know this is an old thread but putting saltwater down the septic probably isn't bad considering most people have water softeners when on a well. The water softeners backwash salt water into your septic nightly [emoji16].