Tap water x RO Water

Fernando Parra · Jul 14, 2017

Hello everyone,

I have a 210 Gallon, my RO filter is not big enough for this size of tank, I would spend several days and a huge amount of water , I am thinking to fill the tank using tap water + conditioner, after that add the salt.

Is it possible or not? Do you guys have any experience doing that?

Thank you,
Fernando Parra

THolden · Jul 14, 2017

Everyone is going to tell you not to do it but I've been using two water for 30 years and have never had an issue.

BlueCursor · Jul 14, 2017

You will regret it. If it takes a week to make the RO you need, take a week.

Tap water has a bunch of phosphate and silicate in it. It has other nasty trace elements you just don't want.

I used to use tap water, but it was well water from a very deep well. The water had no alkalinity, no calcium, hardly anything. It was the perfect well water.

With city water, it's rarely water you want to use.

THolden · Jul 14, 2017

'tap'

babyg2.0 · Jul 14, 2017

I only use tap water and I've never had an issue with any of my tanks, salt or fresh. However, I do have well water so there isn't really any trace elements and our water isn't treated. We have a natural spring in our back yard so we tend to use that for our water. I've never been on city water but I definitely wouldn't use it

saltyfilmfolks · Jul 14, 2017

Tap water quality varies from place to place.
At my house it kills goldfish.

chipmunkofdoom2 · Jul 14, 2017

THolden said:
Everyone is going to tell you not to do it but I've been using two water for 30 years and have never had an issue.

The issue is that not all tap water has the same level of contaminants and impurities. Your tap water may be sufficiently pure so that you don't have issues with using it, and that's fine. But, other reefers may or may not have the same water quality that you do. Getting an RO/DI system is not free, and maintaining one can be a hassle, but it's a guaranteed way to get pure water. The reason "everyone" says to use RO/DI is because to most people, the time and money spent is worth it.

@Fernando Parra you may be able to request a water analysis from your local municipality and see if the water is pure enough to do what you want. However, I personally would just use deionized water. Filling the tank only occurs once. It will be a pain and use a lot of water, but in my opinion it's a cheap insurance policy that ensures you have clean water.

THolden · Jul 14, 2017

I still say it isn't as bad as most want you to believe or admit. I'd agree with you if I hadn't lived in at least 10 different water municipalities over 30 years I've been reefing.

Cory · Jul 16, 2017

In my home town they add phosphate to the water to reduce lead. It was 3.0 ppm!

vanpire · Jul 16, 2017

My tap water also increases the alk to 14 DKH when I mixed with salt. RO water, 11 DKH.

ReeferBee · Jul 16, 2017

Why risk it? If reef keeping has taught me anything over the years it's definitely patience. That and it's not a cheap hobby. So personally I would wait for the slow RODI to fill it up. Tap water quality can vary even in one city. For example if something gets off in the chemistry an over abundance of something else can be used to correct the problem. This can really cause problems for fish and inverts.

PSLReefer · Jul 16, 2017

Should you? Not if you don't have to.
If you don't want to wait or waste all the water use tap, cycle, and use rodi after that.

I have used Tap to cycle the many many tanks in just as many cities throughout the southeast. Ive never, nor know of anyone with issues from doing it.

I vote yes

Rick cowen · Jul 16, 2017

As stated above,depends on the water quality. To me a reef tank is a labor of love, patience,planning, and research is the key to long term success, low stress and maximum enjoyment, I attempted tap water in the city I live in and had issues. Where i live, i would never use tap water.

DSC reef · Jul 16, 2017

Don't risk it. Your just starting a large tank build so take advantage of being patient and you'll wind up with less headaches in the future.

andrewkw · Jul 16, 2017

If you were going to risk it which I don't suggest you do, then you should at least know what you are risking. If you find someone who tells you the answer you want they are going to have no idea what they are talking about because they have no idea your water quality.

"Tap water" can mean anything from 10 TDS or less (very very rare) to unsafe to drink and 500+ tds. Your water might have chloramines for example. When people say RO/DI it's generally assumed to be 0 tds pure water. Also if you can't wait to fill the tank up with clean water you are going to have a real tough time waiting for the tank to be ready for livestock.

Fernando Parra · Jul 17, 2017

Thank you very much everyone! I will choose the traditional way, I will get a better RO filter and be patience! I guess 1 month after I this tank will be filled! Lol
But I would like to thank you all you guys for all support offered to me!
Have a good week!

hart24601 · Jul 17, 2017

Good to hear you are using RO/DI! As others have stated tap water varies greatly in quality. Here in Iowa we have tremendous farm runoff, I use RO water even for my freshwater tanks without question. Our water frequently exceeds the federal legal limit in nitrate along with several ppm phosphate straight from the tap. The organic load is also very high, they use lime to try and remove a good deal of organic matter and the pH from the water works website is 9.67 today.

THolden said:
I still say it isn't as bad as most want you to believe or admit. I'd agree with you if I hadn't lived in at least 10 different water municipalities over 30 years I've been reefing.

Where are some of the municipalities you have lived? Have pictures of your tanks? I have no idea how I could run a system where with tap water...

Rick cowen · Jul 17, 2017

Fernando Parra said:
Thank you very much everyone! I will choose the traditional way, I will get a better RO filter and be patience! I guess 1 month after I this tank will be filled! Lol
But I would like to thank you all you guys for all support offered to me!
Have a good week!

Good to hear, everybody here wants you to succeed

Sharvey103 · Jul 18, 2017

I used tap water before but ran it through two mixed bed resin cartridges to clean it up as much as possible. Better than straight tap water with the impurities that you will fight longer in new tank syndrome.

TangingOut · Jul 18, 2017

Just what RO unit are you using? It may seem slow, but running it non stop over a few days can produce a lot of water. My 90gpd unit filled my 165 in a 1 1/2 days. I get 500-600 tap tds and would never consider putting any of that in my tank.