Dropping RO/DI for top off water?

[MorganAtlanta]

On any other aquarium board, it would be blasphemy to even ask this question... How many people have dropped filtering their top off water since they have gone to using a scrubber? And, have you observed any negative effects?

I never really understood the whole RO/DI thing. I hear (smart, successful) people saying that you can't have *any* TDS in your make up water, not even 1 PPM. But then they throw 5-10 cubes of frozen food in their tank daily (along with amino acids, "coral food", and all sorts of other stuff). It seems to me that any contaminants in the source water would likely be irrelevant once you factor in feeding. Is using RO/DI a herd mentality thing like using skimmers? I suppose if you have really hard well water or something, maybe you need to do something more, but it seems to me that with decent city water, adding a few drops of Prime to take out the chlorine should be all you really need to do.

That said, I use a DI filter and have continued to since I started using a scrubber, mostly due to fear that maybe (smart, successful) people are right about the whole RO/DI thing, but also due to the fact that I have extra DI cartridges that I might as well use up. But, when those are done, I'm wondering if I should drop filtering and just let the scrubber take are of the small amount of anything that gets in the system from the top off water.

[mikepao13]

Hi mate,

Im using RO/DI water as well but my scrubber was set up yesterday so i cannot give any opinion yet.

[SantaMonica]

Using tap water for top-offs is one of the last frontiers of reef tank advancement. Obviously most reefers are just now getting the idea that algae can do all the filtering, but we here are beyond that, and like you said, there is real possibilty of using algae to deal with the tap water too. It works out well on paper, but it's just not tested yet.

A scrubber (algae) does remove most of the "bad" things in tap water (after all, algae does all the filtering in lakes and oceans), 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 for top-offs (it's already assumed that you are not doing water changes anymore, so we are not talking about adding huge amounts of tap water at once; just small amount via top off). Chlorine is definitely NOT removed by algae, but chlorine will, in tiny amounts, evaporate as the water is circulated in the system. Chloramines (chlorine + ammonia) do not evaporate, but fortunately they are broken apart by ascorbate and ascorbic acid, both of which are produced by algae. After the chloramines are broken apart, the chlorine evaporates and the ammonia is eaten by the algae. Again the question is if this is done fast enough.

Some people are experimenting with using tap water instead of RO or RODI, but there are no results yet. I myself have a test 10 gal FW nano that I top off with tap (unconditioned), and for 6 months it's been doing great. I pour in about a gallon of tap water at a time. I also put small amounts of tap into my reef, but not enough to call it "top off". I have enough other experiments going on, so I can't experiment with reef tap water quite yet.

If you have live rock, or live sand, or any corals or inverts at all, 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, again, will the copper be removed fast enough so that no damage occurs when you add the tap water top-off. Nobody has tested this, so it would be an experiment. The best test would be to start with an new tank, and add your corals or inverts one at a time (cheapest first).

The difference between adding food and adding tap, is that the food is mostly organics, whereas the tap is mostly inorganics (nutrients, which do not feed any livestock), and therefore it puts a much larger load on the scrubber. Most reefers, of course, only have skimmers (which do not remove nutrients), so their tanks would be immediately overrun by the tap water. For us scrubber users, it's a matter of degree... more tap needs more algae.

Still, tap water top-off are untested in a reef; there might be something in city water that algae does not remove, which might hurt corals. Someone will have to start testing.

[MorganAtlanta]

I've talked with a successful long-term reefer (no scrubber-- skimmer+fuge w/macro) who doesn't use RO/DI, but does run carbon in a small hang-on-tank filter on his auto top-off tank. That seems like a simple, interesting solution to me for excess organics, but I don't think carbon is good for metals like copper.

[SantaMonica]

Carbon also remove DOC, which is the food you want for the corals. Included in this is the ascorbate and ascorbic acid which break the chloramines apart. Carbon really has no use in a reef tank.

[srusso]

I know what we really need is someone who has been doing it for years, but I have been running my three month old reef tank with tap water and a scrubber. I don't do water changes and I top off with prime treated tap water. Everything has been running very smoothly aside from an ICK issue... but that is not related at all to this topic...
I have never used RO/DI, dont have a skimmer, I am slowly adding things (b/c this stuff it expensive!) Got glove polyps with neon green center and a orange ricordea. As for fish I have a sixline and a lawnmower blenny. Working on getting more live as I can....

One additional thought... it should be said my area has great tap water, I tested TDS and it reads 60 straight from the tap.

[MorganAtlanta]

What I am looking at now is using an API "Tap Water Filter" (carbon block and DI) between my top off bucket and the sump. I can push the water from the bucket through the filter and into the sump at about the suggested rate for the filter using a peristalic pump (which can generate 25 PSI @ 50 ml/min). This will let me fill my top off bucket with tap water, but still give filtered water to the tank. I've found I get over 150 gallons of output for each $20 filter cartridge, which is about four months of top off.

[180rftank]

I moved my 180 reef tank a month or so ago. Go lazy and did not set up my R/O unit for top off until just today. It could of been just a plain fact that when I moved my tank, it went through some stages like when you set up a new tank, or it could of been that for the last month, I was topping off with regular tap water. Regardless, I am battling a red algae problem. I'm also running 2 SM 100's. My phosphates have been up and down between .03 and 1.0. Green algae is also starting ro reapear on my live rock as well. Will keep the updates coming.

[Floyd R Turbo]

The problem I see with the API Tap Water Purifier is that the DI resin will get eaten up in no time flat. My tap water TDS is 580. RO brings it down to 30 (I have a different problem, should be 10-13) and my DI takes it down to zero. but only for a couple hundred gallons. I can't see how DI would last 40 gallons w/o RO in front of it. So I think it's a total waste of money.

As for tap water reef...I think what we need is some scientific studies to show the effectiveness of removal of individual compounds by algae. Otherwise, we're just guessing. There's all kinds of nasty stuff in tap water, I know someone who works for a municipal water treatment facility and you don't want to know. I will not be giving up my RO/DI system anytime soon.

[Aeros]

Hi All,

Just wanted to say I've been running straight city tap for over a year now. Also, there are other reefers in town that have been doing so 5+ yrs.

My experience is purely anecdotal, however, I have a thriving population of a dozen or so acroporas, some LPS and softies. I am currently battling GHA, I don't attribute that to anything but my laziness though.

My city posts their water analysis yearly. I posted one here a while back. Aside from the sodium flouride I was content with everything else. Might even knock out a calcium ion and make stronger skeletons lol.

All tap isn't equal I realize, and results will vary. But there's my experience.

[SantaMonica]

Sounds great. One of my future experiments will be a tap water reef nano.

[180rftank]

Update...I did a water change a couple of days ago using RO water again, and another water change today. Still have a lot of hair algae growing starting to grow in a lot of places on the live rock. Phosphates testing at .07, nitrates undetectable, calcium about 450. Hopefully the hair algae is just the phosphates bleeding out of the live rock. Time will tell. 180 gal reef using only 2 Sm100's.

[SantaMonica]

.07 is high... start a thread with tests and pics of the screens.

[Eclip]

We have pretty bad water in australia but i use carbon filtered water with no prime etc in my tank. you cant taste or smell any chlorine as the carbon takes it out. i do change filters fairly regulary as well.

[MorganAtlanta]

I have the luck of having just 50 ppm TDS in my tap water, which is what lets me get away with a DI-only solution. I'm currently using this same Tap Water Filter to filter the water before I put it in the top off water bin.

[pulse69]

I've been using rain water. do you think this would cause an issue? my tank has been running for 3 months now. My algae screen is getting green hair algae and red turf algae in spots. i need to hook up more lighting to the scrubber but that's a side issue.

[MorganAtlanta]

I thought of using captured rainwater, but I wondered about all the dust and pollen and such that would wash in. I guess it would settle out, but I think using filtered tap water is just easier in the end.

[TheHoove]

I'm new here, learned of Algae scrubbers just a couple weeks ago. I love the concept, and will be building one shortly. In all my research, this was another topic i'm interested in. I ran my tank for 5 years with no RODI water. But My small town water in the mountains of Northern California is very good. Last years annual average TDS was 19. Our tap water tastes like bottled water. Never chlorine taste. I added an RODI unit about a year ago. Havent noticed a change in anything in my tank with better water, only my own comfort. I know there is ways to use the waste water. But Avoiding the system all together may be nice. Not having to heat my RO water in the winter would be nice. When I get my scrubber built I may try removing it. But then, I've had 5 years on my Tap water before with Zero water related issues. So I'm more comfortable with the idea than many may be.

[michael007]

I use a water treatment that breaks the chlorine and metals down in tap water... they are obviously still in the water but does this inturn give the scrubber more time to 'soak' up' these impurities??

[SantaMonica]

A scrubber (algae) does remove most of the "bad" things in tap water (after all, algae does all the filtering in lakes and oceans), 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 for top-offs (it's already assumed that you are not doing water changes anymore, so we are not talking about adding huge amounts of tap water at once; just small amount via top off). Chlorine is definitely NOT removed by algae, but chlorine will, in tiny amounts, evaporate as the water is circulated in the system. Chloramines (chlorine + ammonia) do not evaporate, but fortunately they are broken apart by ascorbate and ascorbic acid, both of which are produced by algae. After the chloramines are broken apart, the chlorine evaporates and the ammonia is eaten by the algae. Again the question is if this is done fast enough.

Some people are experimenting with using tap water instead of RO or RODI, but there are few results yet. I myself have a test 10 gal FW nano that I top off with tap (unconditioned), and for over a year it's been doing great. I pour in about a 1/2 gallon of tap water at a time. I also put small amounts of tap into my reef, but not enough to call it "top off". I have enough other experiments going on, so I can't experiment with reef tap water quite yet.

If you have live rock, or live sand, or any corals or inverts at all, 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, again, will the copper be removed fast enough so that no damage occurs when you add the tap water top-off. Nobody has tested this, so it would be an experiment. The best test would be to start with an new tank, and add your corals or inverts one at a time (cheapest first).

In your mountain water situation, there would be no added chlorine or chloramines or copper. Probably just some nitrate and phosphate that the scrubber would get right away.