RO/DI unit

[Rlumenator]

Our city water is RO; we also have a RO/DI unit on the tank- is this necessary? Some say not. Thank you.

 

[ChrisRD]

More than likely your city water has chlorine or chloramine added to it as a sanitizing agent, among other possible additives. Personally, I would at least run the tap water through a sediment and carbon filter as a precautionary measure before using it in a reef (which is happening when it goes through your RO/DI unit's first two stages).

My advice would be to leave your RO/DI in place. I don't see the benefit to taking the unit off because if it's not doing much, the cartridges will last a very long time and therefore it's not costing much to operate. OTOH, if it is doing something significant and you take it off, you may have negative results down-the-road.

 

[Anonymous]

Municipal RO is only meant to get swamp, well, and seawater to potable water that past EPA requirements. It is not going to get you water as good as residential RO.

 

[Anonymous]

Like arrowhead water "really" coming from a mountain spring in the Alps... :wink:

8)

 

[Anonymous]

I test the Arrowhead water... it is about the same when it comes to TDS of Los Angeles manicipal water... about 250 ppm.

Orange County water is a mixture of RO well and river water. The TDS is around 500 ppm.

For comparision, typical RO is around 5 to 20 ppm of TDS.

 

[Rlumenator]

Cape Coral has a good RO system,(water does not come from the swamo) in addition we are new construction and have a whole house filter on our house. Dawn

 

[Anonymous]

Id still go with an RO/DI unit...better safe then sorry..compare your tap water with a TDS meter and see if its as low as David says..if not then you might wanna get an RO unit...

 

[Rlumenator]

Lord Nikon, I already have an RO/DI- just wondering if it necessary.

 

[Anonymous]

If you have a RO/DI, test your city water and see if it is as good as the RO. If it is 100 TDS or higher, then you need to find out what you want to keep in your fishtank. Some setup are fine with that, but most con't.

If the city water is not good enough, then put the RO on it. You can do away with tap->DI if the tap is very low in TDS, but only a few places in the USA has that good of a water, and I doubt that your city water is that good, but I can't tell until you tell us the TDS reading.

To make our life easier, just put the RO/DI on the tap unless you are confident that the city water is good enough for your tank. You need to tell us what you going to keep, and what is the TDS level in your tap. Without these info, we are just shooting in the dark, and the best possible advice is to tell you to put the filter on it.

 

[mhaynes41]

I test the Arrowhead water... it is about the same when it comes to TDS of Los Angeles manicipal water... about 250 ppm.

Orange County water is a mixture of RO well and river water. The TDS is around 500 ppm.

For comparision, typical RO is around 5 to 20 ppm of TDS.

Wow 500 ppm. where would you find an RO unit to do that high? Most are specd to do around 200 ppm max 250 would do ok but 500 ppm would eat the membran in about a year. As to using DI in most cases it really does not do much if for Lab use yes but for a reef tank? Not really needed. I run two three stage RO units putting out 120 G a day and with a TDS meter my reading are 000 at the most I get a reading of 040 that's only for the frist 20 seconds or so they all do that on membran start up. Both my units are ket marine Hi S I bypassed the DI and used it as a second carbon I have found out that running only 1 carbon you still will have Chlorine / coramine but using a 2 stage carbon it's all gone. Even kent marine told me that DI is really a not needed thing so what can I say?

 

[Anonymous]

I test my RO periodically, and it is fine for at least a year under normal usage (drinking and reef tank). For some locality, the tap water is really good, and so the RO can be very soft, and no need for a DI.

I hardly ever do water change, but I don't really recommand newbies to do what I do. With top offs, it is very important that I use the puriest water possible. After a 3 stage DI, my RO of 10 ppm drops to better than 15MOhm/cm. (After the first stage DI, the TDS is around 0.11 ppm for a old cartidge last time I took the reading.)

I envy your tap water, but unfortunately, we live in a desert, and there is not many choices when it come to water.

 

[mhaynes41]

I test the Arrowhead water... it is about the same when it comes to TDS of Los Angeles manicipal water... about 250 ppm.

Orange County water is a mixture of RO well and river water. The TDS is around 500 ppm.

For comparision, typical RO is around 5 to 20 ppm of TDS.

Wow 500 ppm. where would you find an RO unit to do that high? Most are specd to do around 200 ppm max 250 would do ok but 500 ppm would eat the membran in about a year. As to using DI in most cases it really does not do much if for Lab use yes but for a reef tank? Not really needed. I run two three stage RO units putting out 120 G a day and with a TDS meter my reading are 000 at the most I get a reading of 040 that's only for the frist 20 seconds or so they all do that on membran start up. Both my units are ket marine Hi S I bypassed the DI and used it as a second carbon I have found out that running only 1 carbon you still will have Chlorine / coramine but using a 2 stage carbon it's all gone. Even kent marine told me that DI is really a not needed thing so what can I say?

I understand some places the water stinks really bad so maybe using DI is good just remember never drink DI water a persons body can't take drinking DI water but I guess everyone knows that anyway.

 

[Anonymous]

Actually the issue of DI water for human consumption was addressed in several threads already. The main reason is not that we can't handle the ultrapure water, but rather it is waste of money, and the resin may not be suitable for potable water (VOC and solvent used in the resin manufacture process, etc)