Using tap water?

[FishyLiz]

Hello,

I have a 20 gallon tank with 3 hermit crabs, Pagurus longicarpus. My tank is an "unchilled" tank, definitely not tropical. I also have some Ulva growing in there.

 

I see lots of stuff online about how you shouldn't use tap water in aquaria, but I work in a freshwater lab at my university, and we fill a huge 50gal trash can with tap water and leave it overnight to de-chlorinate it, and the fish do fine. That said, mine is an invert-only tank (no fish). Can I bring home water from the TC at work? I'm wondering if there are other concerns regarding using tap water than algae growth. For example, I've heard copper can be toxic to inverts? And I assume there is copper or other metals in the piping on campus.

 

Thanks!

[Staticmoves]

the gold standard in Marine would be 

Gold = RODI

gold silver = distilled 

bronze  or less = de-chlorinated tap water

 

problem is, no one knows what is in your tap water, depending on where you live and where it comes from. hard question to answer. RODI eliminates these risks and variables.  

[seabass]

31 minutes ago, FishyLiz said:

I'm wondering if there are other concerns regarding using tap water than algae growth.

Other than algae growth, tap water contains low levels of contaminants which are typically considered "safe" to drink.  However, they may not be safe for reef tanks (even inverts), especially when they become more concentrated by topping off evaporated water with more tap water.  Also, the quality of tap water changes from time to time.  If using tap water, I would occasionally change out 100% of the water to avoid concentrating the contaminants.

 

We often look at the risk of losing hundreds (or even thousands) of dollars of livestock by using tap water in a reef.  In your case, the financial loss would be less, but the risk is still there.  I would add RO water to Staticmoves order of water quality, making it:

• RODI - the best
• Distilled - more expensive, but the quality is practically equivalent to a well maintained RODI systeam
• RO - removes a large percentage of contaminants (but not all), which might be an acceptable compromise for you.
• dechlorinated tap water

There are actually a couple of other options, but these are the most popular.  Actually, very few people use dechlorinated tap water for reef tanks; although I'm not sure how many people use it for fish only type tanks.

 

[ryans.salty.crew]

13 minutes ago, seabass said:

Other than algae growth, tap water contains low levels of contaminants which are typically considered "safe" to drink. 

 

I've never used tap water for ATO, my back up is always distilled. I wouldn't because of the unknown. BUT does tap water actually cause algae blooms!? I've never heard this before (Also still new to the hobby. 2 years now)

 

Wow, this is news to me! I have a friend who uses tap and she was wondering why her tank was having crazy algae outbreaks. I GARENTEE that's the reason. I've warned her about doing it hundreds of times. I will relay this information 

[Staticmoves]

research advice you get here, to draw your own conclusions. and always approach advice with a healthy dose of skepticism.

however........ in the case of @seabass.........trust worthy advice......... 😉 

[seabass]

2 hours ago, ryans.salty.crew said:

BUT does tap water actually cause algae blooms!? I've never heard this before (Also still new to the hobby. 2 years now)

There are often detectable nutrients (phosphate or nitrate) in tap water.  Also, some of the trace metals in tap water (like iron) are often sold as plant supplements.

 

But in addition, when you search what's in tap water, you typically get results like: lead, arsenic, PFAS, pharmaceuticals, pesticides, etc. (even herbicides).  Your municipal water provider probably publishes water quality reports (although, like I said earlier, water quality can change after a storm or even due to fire hydrant flushing).

[mcarroll]

2 hours ago, FishyLiz said:

Pagurus longicarpus

From a quick read it sounds like these guys should be tough as nails!

 

2 hours ago, FishyLiz said:

I see lots of stuff online about how you shouldn't use tap water in aquaria, but

That's what you should say about anything everything you read online. 😉   But seriously, that's good advice.  

 

I will pile onto the other good replies you've gotten already...

 

Zillions of people use nothing but tap water on their tanks all the time and have no issues.  How?  

 

You have to put the "no tap water" advice in context, otherwise it's useless and confusing.  Why shouldn't it be used?  You mentioned algae promotion, but clearly that's not a universal experience.  So what gives?

 

2 hours ago, FishyLiz said:

Can I bring home water from the TC at work?

If you have a bucket to bring water home in, just fill it with topwater at your house and wait 24 hours – no point in lugging it around more than necessary.  (Chemical dechlorinaters like Seachem Prime are faster and cheap, but as you've noticed these are also not 100% necessary if you have time and a little space.)

 

2 hours ago, FishyLiz said:

I'm wondering if there are other concerns regarding using tap water than algae growth. For example, I've heard copper can be toxic to inverts? And I assume there is copper or other metals in the piping on campus.

Again, context matters here.  

 

What's in YOUR water?  Are you dependent on fossil water?  ...surface water?  ...Arizona water?  Are you in an area with farming and therefore farm runoff in the water?  

 

If you're on a municipal water supply, it's probably tested regularly and you should be able to look up past water reports online or call them for the most current report.  If not, it's probably worth getting your tap water tested at least once, but maybe regularly.

 

Copper has a significantly high dose even to take out microscopic critters like dino's and Crypto....not gonna happen from pipe leaching.  Most locales have phosphates (or something else) in the water, or purpose or naturally, to promote a little scaling that should protect the copper from leaching for the most part.  

 

BTW, if your water is acidic enough to make copper levels a problem, you should probably do something about it vs just worrying about copper levels in the water – your pipes are dissolving!! 😉 💦

 

Inverts are generally considered more sensitive than "higher animals" like fish and your inverts are apparently doing fine.  Whatever you do, take your time while you gather the info you're looking for.  👍

 

 

FYI, there are lots of GOOD things in tap water too, like minerals and buffers, even if you don't have a reef.  Nothing would be happy living in RODI water for very long.  The reason we use it is A) we have a complete water mix (eg Instant Ocean) that includes EVERYTHING to make saltwater and B) it's a perfect replacement for water that evaporates from a saltwater tank – some of us have to replace 5 gallons a week or more!  No minerals leave the tank during evaporation, so using water with ANY minerals in it will skew the seawater balance in the tank.  Even so, some folks still use tap water for saltwater tanks....usually fish-only systems, but not always.  As far as I know, there's still one brand of salt mix that includes dechlorinator for just such a purpose.  (It's not widely popular in the hobby.....mostly in labs I thinks.)

 

Reef Tank

If you were running a reef tank (which does not appear to be the case), then you would have some other issues to consider.  (Similar issues with a freshwater planted tank.)  The bright lights used will cause something to grow, if it isn't coral (or plants) it WILL be algae.  So in that case, tap water with high nutrient levels (eg nitrates) can really fuel an algae bloom – especially if you aren't aware and ready for it.   In addition, there are other issues that can affect corals when nutrient are driven far out of balance by something like this.

 

1 hour ago, ryans.salty.crew said:

Wow, this is news to me! I have a friend who uses tap and she was wondering why her tank was having crazy algae outbreaks. I GARENTEE that's the reason. I've warned her about doing it hundreds of times. I will relay this information 

If you're in an area with a lot of farming, then it's likely.  But otherwise not.  It also could be fairly seasonal, following the tilling/fertilizing schedule of the farms around you.  Test the water, no need to guess – this is a good use for quick-test strips.  Cheap and FAST.