Storing water

After reading so many post about keeping a salty tank without to much equipment, I am thinking of changing my goldie tank to one of these tanks that Mike (granocompany) has got.
My question is, if I was to buy salt water pre-made from seahorse of instance, how long does it keep in a barrel before it's no good.
Eg. If I was to get 100 liters once a month and do a water change of 25 liters a week, would the last 25 liters I have stored still be fine in 3 weeks time?
Any thoughts?

How big is the tank??? You should only need to be doing between 5 and 10% waterchange..

Seahorse recomed you only store it for a,week .....2 week's at very most..

If you were to buy 100 litres to fill the tank and 100 litres for water changes and add in the cost of deposits for containers....just that alone is probly about 100 Euro


You'd easily pick up a secondhamd ro unit and a small bucket of salt for that amount.......


Just mix it then when ever you want it.

I knew someone would know the answer.
It just now Bart has built my new tank ( still waiting to fill it, sorry, so no photos yet ) I was thinking of trying my hand at turning my small Jewel tank (2 foot by 1 foot by 18 inches high, external tetratec filter that I could fill with coral) into something salty.
I didn't realise that you change so little water in a salt tank, and if store brought water only lasts a week, an RO and salt seem easily the best idea.
Was thinking of stocking it with a few simple corals and a few small fish. Not exactly sure yet though, but it will be a shame to have an empty tank!

I've stored freshly mixed SW for a month or more with no issues. Just make sure it's always being circulated well.

With the proviso that I don't do salty:

Top ups for reef systems need to be made with considerations to evaporation and salinity.
Topping up with pre-made is a recipie for disaster? No?

Discuss...........

murph wrote: With the proviso that I don't do salty:

Top ups for reef systems need to be made with considerations to evaporation and salinity.
Topping up with pre-made is a recipie for disaster? No?

Discuss...........

Do you mean storing FW in a storage container that is then used as topoff water for your SW tank? Many people do that using an ATO unit. I only suggest you add a small pump to the container to prevent the water from becoming stagnant. And you can add kalk to this to maintain alk/cal levels.

I asked was, how long can you store salt water to top up a salt water tank, and that seems to be a week or so.
But I would think what 'murph' says it true. You can just add ready made salt water to a tank else it will get too salty over time, due to water evaporating from the tank.
So does FW need to be added to keep salt levels ok between water changes, or is it when you do a water change you make it less salty to fill the tank and restore salt levels.
Confused now

I think I understand now, but I admit I'm a little confused as well. So my apologies if this still isn't answering your question.

Your saltwater tank will evaporate water everyday. For example, my 500+ liter reef evaporates a gallon or two a day depending upon the time of year. However, only freshwater evaporates from your saltwater tank so you must replenish (or topoff) with freshwater everyday (or as needed). Otherwise, your salinity will just keep going up & up. You want to keep the salinity as stable as possible for the overall well being of the animals you keep.

Forgive me for going on a slight tangant, humblefish, you're saying your reef tank losses 10% water a day from evaporation?, my tank losses that a week with an open sump and covered tank.

paulv wrote: Forgive me for going on a slight tangant, humblefish, you're saying your reef tank losses 10% water a day from evaporation?, my tank losses that a week with an open sump and covered tank.

Oh no, not 10% a day. My 200 gal system (150 gallon aquarium plus 50 gallon sump) evaporates a gallon or two per day. So, that's only 1% even on a bad day. A bad day is usually in the winter when all the space heaters are running full blast.