Tap water for fish-only tanks?

[JTP424]

Also! You should only need to carry the 20 gallons once to fill it up! Afterwards it would only be like 5 gallons at a time of RO or Saltwater. You shouldn't need more than that weekly. With a 10% water change weekly... that's like 2 gallons...

*Edit - I have a 15 gallon and when I started I was doing a 5 gallon run every two weeks for RO water, covered my water changes (made my own salt, 2 gallons at a time) and topoff

I then invested in an RO buddy, I just replace the whole thing every other year or so...

 

[AetherealKnight]

Just curious, how is water changes with the same water going to help with algae growth?

Im just saying that regular water changes should be used as a way to export nitrate, to combat algae growth.

But yes you’re right and I agree with you that tap water is not ideal as it likely contains nitrate and other unwanted chemicals.

 

[AetherealKnight]

You cannot compare the requirements of humans with ocean animals.

Human are much more complex and have better methods of filtering and adapting to various pollutants and water chemistry to maintain homeostasis.

I've tried running FOWLR tanks on tap water and it did not end well for me.

Of course the water out of every tap will be different so you may get lucky if you play the game of Russian roulette with your animals.

FWIW, Carbon does not remove all pollutants that are potentially harmful to animals.

I stand corrected, you are right. I initially used tap water in my early days of reefing after treating it water conditioner. But looking back it was not the best option. I recommend the OP invest in a RODI system, If you want to avoid long term problems. Investing a RODI should be relatively cheap compared to the costs of live stock in this hobby.

 

[drbrivers]

It really depends in my view on whether your local tap water has chloramine instead of just chlorine. If the tap water only has chlorine you may well be just fine for a fish only system using a dechlorinator product to neutralize the chlorine. If you don't neutralize the chlorine you can kill off your tank biological filtration. But if you have chloramine that is a whole different situation. Basically ammonia bound to chlorine. When you add a dechlorinator you break the bond and while the dechlorinator deactivates the chlorine now you have Ammonia available. The problem is you won't know how much ammonia will now be in the water to use for top of or making new saltwater and it can be very high depending where you live. You could end up with ammonia level high enough for fish mortality. So if you have only chlorine in your tap it would be reasonable to try it using it after putting a dechlorinator in it. But if you do have chloramine then it is best to use at least RO source water. DI would be optional for fish only. Check with your local water company/municipality to see if chloramine is used in your tap.

 

[KrisReef]

If you have a municipal water supply that provides your water you should be able to get a report from them by using your local Google Browser (if you have one?) and find out what they have found in your tap water.

Post that report or a link to it here and then we can talk about what you need to filter out, if anything. Most Tap water has antibacterial agents added and those are usually easy to remove. Some tap water is heavy with industrial pollutants like Uranium or petroleum and other toxic substances that may have negative impacts on your reef tank long term.

If stuff like that is present you will want to filter the tank water to protect your fish?

 

[klc]

Can you keep a marine fish tank using tap water? Sure, we did it for many years before rodi was a common thing. In 1985 the internet didn't exist so you had to rely on what your LFS had, and RO systems typically wasn't one of them. DI resin? Yeah right, what's that? The fish nowadays aren't any different than what we kept 40 years ago. Hobbyists would use 2 conditioners with the tap water, Amquel and Novaqua, one detoxified chloramines and heavy metals and the other provided a slime coat for the fish. We had no issues.

I'm not saying use tap water in all circumstances, I wouldn't keep a conspicuous angel in tap water, but I'm just saying it IS possible to keep most commonly available marine fish for a 20g in treated tap water. I feel the OP is trying to keep the financial burden of a small salt water tank to a minimum.