Can you use dechlorinated tap water in a saltwater aquarium?

[FirePanda]

I’m new to saltwater, but I do have a dad who has kept a saltwater aquarium, and he says you have to do water changes a lot on a saltwater aquarium: how many for a 40 gallon breeder, and can dechlorinated tap water be used for them? My water is very hard, about 220 ppm. Not sure if that matters much for saltwater. Also, I want a reef: does it matter for a reef tank?

[SLA10]

I have run saltwater tanks on dechlorinated tapwater, it can be done.  They were fish only tanks years ago.  But rodi systems are not that expensive anymore, if you want to run a reef system, you'll have better results with rodi.  Truthfully the least expensive part of a reef tank is the water, your going to spend alot more on fish/corals nowadays.

[SLA10]

And for water changes, ballpark is 10% weekly, but there are options and with dosing, ato, where some people do almost no water changes, but your gonna want to start with water changes.

[FirePanda]

Alright, ten percent a week is fine. I was worried it was like keeping discus and you had to do crazy water changes every day to keep them alive. If rodi’s not expensive, though, I’ll get a system. 

[mcarroll]

4 hours ago, FirePanda said:

I’m new to saltwater, but I do have a dad who has kept a saltwater aquarium, and he says you have to do water changes a lot on a saltwater aquarium: how many for a 40 gallon breeder, and can dechlorinated tap water be used for them? My water is very hard, about 220 ppm. Not sure if that matters much for saltwater. Also, I want a reef: does it matter for a reef tank?

The only difference that would mean more water changes is the higher pH of saltwater.  At that level, ammonia is much more toxic.  So if you're starting a new tank by causing an ammonia spike, it's going to be more toxic than doing the same thing in a low-pH freshwater tank.

 

It's somewhat myth though as ammonia is less toxic to most marine fish....and nitrite is completely non-toxic.

 

Not to mention causing an ammonia spike on purpose isn't the best/smartest way to start a tank.

 

220 ppm TDS isn't "very hard".  1200 ppm TDS would be very hard water.  Either way, it's not optimal if you're keeping a reef.   Much less of a big deal if you're keeping only hardy fish.

 

Worth checking out this article as a starting point on saltwater:  http://reefkeeping.com/issues/2004-05/rhf/index.htm

[MLS_Reef]

In general, I would not used tap water only for a reef. If you are going to use a dechlorinator you should check your water municipality and see how they disinfect. If they use chlorine vs. Chloramine. If they use chloramine you have to get a better dechlorinator like Amquel that will bind the ammonia portion of the chloramine. If you dont you end up with high nitrates. 

 

They used chloramine where I live and if my carbon filter or RO filter gets old nitrates would show up in my fresh salt mix. 

I recommend at least a good carbon filter for even a fish only tank. Filters are cheap..

 

[Superdave]

Most local water supplies have much higher nitrates than you want to introduce into your tank.  Won't be the end of the world exactly, but if you get nuisance algae build up you will know why.  

 

To me, it is not worth it.  Either buy water from the LFS or, if you end up getting a big enough tank, an RODI system might be worth it.  Keep in mind that the RODI systems have crazy levels of "waste water" as in 4-5 gallons of water to create 1 gallon of RODI.  

[MLS_Reef]

27 minutes ago, Superdave said:

Most local water supplies have much higher nitrates than you want to introduce into your tank.  Won't be the end of the world exactly, but if you get nuisance algae build up you will know why.  

 

To me, it is not worth it.  Either buy water from the LFS or, if you end up getting a big enough tank, an RODI system might be worth it.  Keep in mind that the RODI systems have crazy levels of "waste water" as in 4-5 gallons of water to create 1 gallon of RODI.  

Good point. My lfs sells 1.025 saltwater for .89 a gallon, if you have a ten gallon tank you can fill it and have 10 10% water changes for 20 bucks

[mcarroll]

1 hour ago, MLS_Reef said:

Good point. My lfs sells 1.025 saltwater for .89 a gallon, if you have a ten gallon tank you can fill it and have 10 10% water changes for 20 bucks

I think this is a great option up to about 55 gallon tank size....you're hauling A LOT of water once you get to that point or larger.  A filter starts to make a lot of sense.

 

Also, just to point it out, nothing is cheaper in the long run than running an RODI filter.  Even with the cost of waste and filter media figured in, it makes water almost for free.....around 5¢ a gallon or so.

 

But when you're starting out and not sure you're going to like the hobby yet, buying water at the LFS (or grocery) is definitely better.   Buy the RODI once you're committed tho.  👍

[MLS_Reef]

@FirePanda What size tank are we talking about? When I was running my I am 10 and I didn't have an RO filter I would buy gallons of distilled water off the supermarket Shelf for top off

[Tired]

Generally it's not advisable to use tap, no. 

 

10% a week is a good starting estimate, but plenty of people wind up doing less than that- it varies depending on the individual system. You can reduce water change needs by (among other things) keeping only a few stony corals and/or dosing to replace the elements that stony corals need, and by keeping corals that don't mind higher nutrients.