RODI water smells..

[Chad and Jen May]

... like chlorine?? We took a water sample to LFS and it tested fine for TDS/Nitrate/etc... what could cause the chlorine smell? Filters in RODI are almost 6 months old, we fill about 50 gallons every two weeks. Im going to use Prime in my jugs for now, but worried about chlorine actually being in my water.

[Aaarrrggg]

Mine started doing that too. I changed both RO and DI filters and it fixed it. Apparently you're supposed to change the DI filter every 6mths regardless of your TDS reading.

[+Hydro]

I don't think that RO/DI membranes will remove chlorine (I could be wrong), carbon will though. Is one of your prefilters for the ro/di carbon, usually it is. If not that would fix it for you. Another suggestion is to simply areate the water heavily once you filter it for 24 hrs or so, that will get rid of it.

[+Hydro]

On wiki

Reef aquariums

Many reef aquarium keepers use reverse osmosis systems for their artificial mixture of seawater. Ordinary tap water can often contain excessive chlorine, chloramines, copper, nitrogen, phosphates, silicates, or many other chemicals detrimental to the sensitive organisms in a reef environment. Contaminants such as nitrogen compounds and phosphates can lead to excessive, and unwanted, algae growth. An effective combination of both reverse osmosis and deionization (RO/DI) is the most popular among reef aquarium keepers, and is preferred above other water purification processes due to the low cost of ownership and minimal operating costs. Where chlorine and chloramines are found in the water, carbon filtration is needed before the membrane, as the common residential membrane used by reef keepers does not cope with these compounds.

[Chad and Jen May]

Yes, it does have a carbon filter... I will change out my filters and see if that helps, thanks!

[Bill B]

Most people say they are not necessary but I have the activated carbon and another cartridge? which are for choloramine, which is appararently harder to block than chlorine. These were an upgrade from the standard stuff that comes in RO DIs from BRS

[Timfish]

This is probably a bit of a history story which dates me but here's what I know. ROs use two different types of membranes. One is called a CTA and needs chlorine in the water to maintain the membrane so the carbon filter is in line AFTER the RO membrane, CTA is used in smaller rated units as it does not produce as much at municipal water pressures. The other is called a TFC which is damaged by chlorine so the carbon filter has to go inline BEFORE the membrane, TFC membranes produce a lot more filtrate at municipal water pressures and is by far the more common membrane used. Niether will remove chlorine or ammonia from the water so it is imperative a carbon filter is used and maintained. Also, after the chloramines are broken down and the chlorine is removed by the carbon filter ammonia is still left in the water and is not removed by the RO membrane. If you want to remove the ammonia you still have to use a product targeted for it. (I don't worry about it myself.) I haven't checked recently but the last time I did RO membranes should be replace every few years (has something to do with bacterial films forming inside the membrane if I remember right)