Does R.O. affect ALK?

Minnreefer · 11-01-2001, 10:44 PM

As many may know we don't have an R.O. unit, we do have a Kold Sterilizer unit which seems to work fine. In Minn we have VERY hard water. Brooke measured the ALK of our new water and it measured 20. Would an R.O. unit make any difference on ALK?

Thanks

Jon & Brooke

gottareef · 11-02-2001, 08:33 AM

Ultrapure water should theoretically have zero buffering capacity, since there are no dissolved salts. One thing I would definitely recommend if you intend to treat very hard water with RO is to put a water softener upstream of the RO unit. The RO membrane will last much, much longer and if you then stick a mixed bed DI cartridge at the end, well, I don't think you can do much better than that. Then again, if the only thing in the water is sodium or potassium carbonate/bicarbonate, why go to all the trouble to filter it out just so you can put it back in again

. I personally do because I got a copy of the allowable limits of contaminants from the water department

. Now I drink the softened/RO and use the softened/RO/DI for the tank.

Doug1 · 11-02-2001, 08:56 AM

Hey Jon/Brooke, one of the benefits touted by the Kold Steril manufacturers(at list in reef trade) is that it removes the harmful crap with out stripping Ca,Mg and stuff like that. So on that basis it should have some buffering effect left over, tho once you add salt mix to RO water its restored to a certain extent. I use the alk part of the 2 part in my RO topoff container and dose the Ca part by hand

Rick O · 11-02-2001, 10:55 AM

When I first got my RO unit I questioned Kent's tech guy about how to tell if your RO membrane was still functioning properly. His reply was that the product water should measure zero for alk with a properly functioning RO membrane.

HTH

Brooke · 11-02-2001, 12:52 PM

Jon didn't mention that it was newly mixed saltwater that measured over 20dkh on a salifert kit. this might explain the high kh in our tank. so, needless to say we did NOT change the water. I don't think the salifert kit will work on freshwater, but I might try just to see what of water is coming out of the kold-steril unit.

Brooke

Rick O · 11-02-2001, 01:42 PM

For some reason I thought I heard or read somewhere that the test kits are not specific for SW or FW. I just checked the box on my Salifert test kit and it didn't specify either.

galleon · 11-02-2001, 02:59 PM

No, R.O. filters would not remove alkalinity from the water they are purifying. Alkalinity is a collection of ion types. You need a D.I. unit to get rid of it/them.