RO or RO/DI water

[Raul]

I been very confused lately with this water issue, my home already had an RO system which I already checked with a TDS meter:


Incoming water is around 260ppm and out of the RO unit is around 10ppm that is about 96% efficient, now I read on online that the water for marine and reefs has to be absolutely DI water which will take it to 0ppm TDS, is that really true, should I bother and get me a DI inline filter and connect it after my system just for the aquarium, my tank has been doing very good with my current water, so not sure.

I have seen some people filling up water in the LFS and well not to question them but I doubt all of the LFS are running DI water or maybe they are.

--Raul.

[johnnymisty]

Ya its best to run DI it shouldn't cost to much to add the DI stage bulkreefsupply.com should be one of the better places to get one from

[mnemenoi]

I would think your water was fine. I believe the idea is to reduce as many minerals (TDS) out of the water as possible and to start with a constant TDS for adding your salt. I'd imagine swings of +/- 20 ppm are really trivial and would not be noticed. If one were using tap water, I think the TDS varies heavily and thus every water change varies your parameters widely and can stress the inverts. From my knowledge, every filter usually has some trace amount of TDS and will increase as the filter ages.

[rage]

I would think your water was fine. I believe the idea is to reduce as many minerals (TDS) out of the water as possible and to start with a constant TDS for adding your salt. I'd imagine swings of +/- 20 ppm are really trivial and would not be noticed. If one were using tap water, I think the TDS varies heavily and thus every water change varies your parameters widely and can stress the inverts. From my knowledge, every filter usually has some trace amount of TDS and will increase as the filter ages.

I think it depends on what you keep to know what is fine and what is not.

Some people keep fish only, treated tap water is ok for their fish but they might get nuisance algae.
For corals, some are more sensitive than others. Some can tolerate water with 10-20 ppm of minerals and other stuffs, some other corals might like pristine water with 0 ppm.

If you start with RO/ DI water with 0 ppm, you are assured your water is as good as it can be. (and if your system TDS creeps up high enough, it's time to change your filter)

If you start with RO water with 10-20 ppm, your system might be ok for a while but remember only pure water evaporates, the bad stuffs stay in your system. Water change may dilute it but does not remove all (just as how you reduce nitrate).

Your call.

[mnemenoi]

Thanks Rage! I'm a freshwater keeper that only deals with softwater tanks and TDS monitoring casually, lol. I had some SW tanks years ago, but its become much more ballin since the eary 90's...

[Raul]

well I will get me a inline DI filter and just put a TEE before the RO faucet and use that only for filling up the tank.

[cobraden]

Your water is just fine. It's easy to read a ton of stuff and get confused. Like anything else there is always little tweeks you can do but getting to zero even though possible, it's not necessary. I know for sure that the water you get from one very popular LFS isn't zero as when I got water from them we both went and looked at his tds meter. Don't stress. you are doing more than many to get your water to a more pure state. I bet there are a few reading this that are using straight tap water.

If you like gadgets, like I do, and you just want to add the DI, do it. It's easy and you can say you took that next step. To me the expense and time of getting that last 10ppm wouldn't be worth it if I didn't already have it.

That's just my opinion though

[Darbex]

I agree with Rage. It all depends on what you want in your tank

[Raul]

well since I like gadgets and for now I do not want to really spend the money I just went and got this:

http://www.amazon.com/gp/product/B007MEVRM2/ref=oh_details_o00_s00_i00

and will connect it just before it hits my RO faucet with a TEE then I Can use that output for the aquarium, then one of this days I will get a enclosure where i can just replace the media.

[Darbex]

In the end this will cost you more because you will have to replace the whole thing everytime it runs out. whereas the BRS one you can just replace the resin. When you say before your RO faucet does that mean after it runs through the RO unit and before it comes out with clean water?

[Raul]

yes well for now I will just add this temporary DI filter and then will get me later the enclosure for a resin, it is all going to be quick connect to easy to replace.

yes and I will hook it after it runs through the RO system and the water is already 10ppm into the DI filter I assume that will remove it close to zero, well I hope.

I will assume the less the particles it has to remove the prolonged used of the filter.

[Darbex]

How long have you had the RO membrane? Most should get the ppm to around 4 or so 10 seems a little high.

[Raul]

i had it for 3 years, and this system is one of the culligan RO systems it was already installed at the house when I got it, so I been just replacing the filters. I will probably order a new RO membrane. The only problem I am stuck with their filters.

[Darbex]

Yeah I think depending on usage its recommended to replace every year.