R/O DO water a must to start a sw tank??

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Heineken

Aquarium Advice Activist
Joined
Oct 15, 2004
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Los Angeles, CA
Forgive my ignorance but with my current fw system I just use tap water and put additives in the water to stabalize the levels of chorine/chloramine etc. Obviously sw tanks require more care and precision, but are there chemicals that can be added to do the same for sw tanks?
If the answer to the above question is no, then how do I go about filling my tank with the R/O water? Where do I get it from and how much does it cost? I have a 90g tank, do you recomend me getting a RO filter? Or should I not worry about getting one. Thanks for the help and replies everyone.
 
The same chemicals which neutralize chlorines (sodium thiosulfate) works just the same with salt water. It all depends on what your tap water has in it. Nitrates and phosphates are things you want to keep as low as possible from everything I've read, and it doesn't do much good to start a tank with 20ppm of nitrates when you're shooting for <10.

Some LFS carry RO/DI (Reverse osmosis, deionized) water. I've seen 20-40c/gallon. But its a pain to carry 90 gallons of water :)

I got a RO/DI unit for ~$100 on eBay from aquasafecanada (2006R). A US company with the ebay user name filterdirect has something similar for about the same prices (make sure you count shipping). Even though you don't need an RO pressure tank for an aquarium setup, I like it to do topoffs (no waiting for the first 3 gallons, RO/DI units can be SLOW when you have lower water pressure and temperature).
 
i am getting ready to start up my tank too. i notice that a lot of sw enthusiats in my area have been really successful using tap water and novaqua to neutralize the chlorine and chloramines. i checked the water test results in my area and i don't see anything alarming. so i am thinking, why spend the money on an RO/DI unit. i hate to have to spend the $$$ if it is not necessary!
 
It's not that there is generally anything alarming in the water, it's the water quality in general. For chlorine, all you need to do is leave the water out overnight and it will evaporate naturally without adding any chemicals to your water. And chlorine in small doses won't wipe a larger tank. I was at one time guilty of sometimes going straight from tap to tank if I had forgotten to set my water out the night before. My tank did fine, but with normal tap water I never saw my in tank nitrates go below 20 as my tap water was consitently at that level. That was a dsb, macro algae and running a skimmer 24/7 in a very lightly stocked tank.

As I said, it's the water quality we're after. A reef tank does much better at little to no nitrate/phosphate. Corals will live longer and look better, and some very sensitive creatures won't tolerate anything above 10-20ppm of nitrate. The RO filters will remove the nitrate and other stuff from your water so you are not constantly adding something you want to be rid of. I'm currently using RO water for top-off, haven't done a water change in a length of time that will get me seriously yelled at around here, and running only dsb and a handfull of macro, no skimmer. I have 8 fish compared to the 2 I did have, and feed daily as opposed to every other day in my old tank. I've yet to see my 'trates go above 10.

So no, it's not a must, but it does help things out considerably.
 
Chlorine may evaporate naturally in a short period of time, but chloramines take quite a bit longer.

You have been lucky by using tapwater straight into your tank. Chlorine is very harmful to fish and inverts and could very easily kill them all and/or cause long- or short-term health problems.

RO water is not a must, but it takes away a lot of the guesswork and luck involved. It's one of the few things in this hobby we can choose to take full control over...I'd personally choose to use an RO or RO/DI unit over adding any chemicals to my water. It's a much more natural, easy, and effective way to ensure good water quality.

The water coming out of my tap is 150 TDS ppm, and my RO unit gets this down to between 001 and 002. It's worth it! My nitrates and phosphates are 0, and I actually know that the water I'm putting in my tank is the best it can be.
 
You have been lucky by using tapwater straight into your tank. Chlorine is very harmful to fish and inverts and could very easily kill them all and/or cause long- or short-term health problems.

RO water is not a must, but it takes away a lot of the guesswork and luck involved. It's one of the few things in this hobby we can choose to take full control over...I'd personally choose to use an RO or RO/DI unit over adding any chemicals to my water. It's a much more natural, easy, and effective way to ensure good water quality.

The water coming out of my tap is 150 TDS ppm, and my RO unit gets this down to between 001 and 002. It's worth it! My nitrates and phosphates are 0, and I actually know that the water I'm putting in my tank is the best it can be.
completely agree...Id rather have water thats had stuff taken out of it rather than adding to it :fadein:
 
ONe thing to keep in mind is that for topoffs, you NEED RODI, since any amount of toxins added will concentrate over time as water (but not bad stuff) evaporates. So if you're 1/10th of the toxic level at first, over time you'll build up to 10/10 and things die.

So, for me, I knew I'd need RODI anyway, so I just bought the ebay filterdirect one. It's currently filling my tank (yeah slow!) As a nice side effect, my coffee this morning was excellent having come off the RODI instead of the well water -> britta I'm used to.
 
Chloramines may evaporate naturally in a short period of time, but chlorine itself takes quite a bit longer.

I believe you have got it backwards. Chloramines are made up of a mixture of ammonia and chlorine and it is highly stable. Chlorine, on the other hand, it not stable at all and will dissipate quickly if the water is aerated or left set out overnight with the lid of the top of the container.

I agree with everyone else that RO water should really be a requirement in my opinion. It removes so much "stuff" from the water, it is unbelievable.
 
Thanks for all the advice guys. The info. has been very helpful. I'm pretty sure that I'll go with the R/O DI route. Guitarded, I'm originally from Hawaii too, just in L.A. for college. I grew up in Kailua. How's the football team doing? Anyway, I know where you're coming from when you said you used tap water. I think that Hawaii is the only place in the country that you can get away with that.

Back to the topic, I've also heard that you can get away with distilled water. Is this correct? I only ask because it seems like it would take forever for my tank to fill with the R/O unit. I was thinking that I could use distilled water to cycle my tank, then use R/O to topoff and for water changes. Will this work?
 
distilled water is just as good as long as it is actually distilled water. Some hacks run water through a carbon and poly filter and call it distilled water. So as long as you have a reliable source, distilled is ok.
 
I think it may take just as long to fill the tank with a distiller than it would with a RO unit, however. My parents have a distiller and it takes them over an hour to get a gallon of water. That is about the same rate my RO unit runs at.
 
Thanks Biggen, post edited :p

Best thing to do would be to test the distilled water you plan to use, before you actually use it. Probably even test each bottle you get, just in case.

Test it for chlorine/chloramines, and get a TDS meter to test the Total Dissolved Solids. These should ideally be well under 10ppm. If not, an RO/DI unit will be much more efficient.
 
hmm... i guess some are under the impression that i have been lucky filling my tank with tap water. actually, as my posts states, i am getting ready to start my tank and noted that other enthusiasts in my area have been successfully using tap water. i will still be researching before putting a single drop of water in my tank.

btw, i have been using tap water in my FW tanks for several years and have 0 nitrates!

hey, heiniken... the UH football team have been doing badly on the road! good luck with college!
 
ok, so i am convinced. i bought an ro/di unit off of ebay!

as soon as i get it i will start filling my tank. it is rated at 110gal/day. it will probably take the better part of the day to fill my 75gal tank!
 
Cool, congrats on the purchase!!! If you don't mind me asking, how much did you pay for it and which model did you get?
 
110GPD RO+DI REVERSE OSMOSIS FILTER - $86.

i think it is pretty much the same as what others on this forum have purchased on ebay. the supplier's ebay handle is "filterdirect".
 
It took me 3 days off and on to fill my 54... but then I have COLD well water at low pressure. I only filled it while I was home too.
 
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