Good bye RODI?

[Moe]

Hi just wondering if you start running a ATS, could you stop using RODI and then just use plain tap water for top-ups?

[ocean rock]

no you will still need ro water its a must

[Moe]

Why is that? If the ATS pulls out so much phosphate and heavy metals?

[SantaMonica]

A scrubber does remove most of the "bad" things in tap water, but it is not known yet if they are ALL removed. And what certainly is not known is if they are removed fast enough for you to put tap water right into your tank. Chlorine is definitely NOT removed by scrubbers, but chlorine will evaporate in a day or so if the water is circulated in an open container BEFORE puting it in the tank. Chloramines (chlorine + ammonia), however, are another matter. They are added by some city water systems, and they are not removed by scrubbers (and they do not evaporate). So if you are not using RO or RODI water, you must use an additive to remove chloramines (if your city water has chloramines; ask them). Water from a well should be fine, since no chlorine or chloramines are added.

Some people are experimenting with using tap water instead of RO or RODI, but there are no results yet. A fish-only (no rock, no sand) tank is probably fine, if you have no chloramines, and if you let the water circulate for a day before using it (to remove chlorine). If you have chloramines, you can use an additive to remove the chlorine and chloramines right away, without having to wait a day.

If you have live rock, or live sand, or any corals or inverts at all, then your problem becomes copper. Copper can occur in city water or in wells. Yes a scrubber (i.e., algae) consumes copper, but the question is, will the copper be removed fast enough so that no damage occurs when you add the tap water. Nobody has tested this, so it would be an experiment. For best chances, you'd want an oversize scrubber, with powerful lighting, and strong flow, along with cleaning every 7 days no matter what. The best way would be to start with an new tank, and add your corals or inverts one at a time (cheapest first). This would be a good test for someone to try.

[Aeros]

As a RO/DI is not within my budget at this time, I have been using tap water to top off and in my salt mix.

I do use a PUR water filter (the kind that attaches to the faucet) to reduce Cl., and I have tried to get in the habit of letting the water 'stand' overnight to let the Cl. boil off. Also, I fill my reservoir with 'hot' tap to facilitate the process.

I mix my salt a week in advanced in a ~20 gal plastic bin with aeration. I do a 10 gal WC, then refill with tap and mix in more salt and let stand with a powerhead and aeration till the next WC.

As for the 'other' goodies in my tap water: My local water Dept. posts an analysis online http://www.stevenspointwaterdpt.org/...ranalysis.html

As for my reef: Aside from my blue hippo's ich and yellow tang's HLLD (I bought him with it not knowing what it was, he's is recovering slowly though. Hope there's no scarring), all my corals have doubled or tripled in size since December, and since adding my ATS all the hair algae has dissipated from the display (thanks mostly to the yellow tang) as well as the red cyano, and nitrates dropped from ~80 to ~10ppm. And pods galore!

All that being said, I will be investing in an RO/DI as soon as possible. For peace of mind mostly, and as part of an ATO set-up; manual topping off sucks. But I don't feel it's necessary.

[Moe]

mmm... I wonder how fluoride effects corals. Probably turn them a sparkling white like our teeth i bet (not that I haven't seen evidence against water flouridation)!

Is fluoride a metal? I'll stick to using my RODI for now, but I wouldn't mind seeing some experiments done.

Adding some tap water to salt mix and install a scrubber and then measure rates of copper, fluoride and chlorine/mine (and whatever else) over time. Would be interesting to see the result.

Thanks!

[Amphiprion]

No, fluoride is a halogen ion, not a metal. To my knowledge, there is no real info on what effect (especially a beneficial one) fluoride has on corals, short of cytotoxicity, much like iodine, bromine, and chlorine. The ionized form should be much less toxic than the free fluorine (F2), but it would still be a problem in certain concentrations--now what those are, who knows.

[Moe]

very interesting, thanks for the information.