Premixing Saltwater?

droth

I wanted to ask about mixing your saltwater. Presently I’m cleaning and changing about 25% of my water on a weekly basis. Changing water weekly means mixing a lot of saltwater and I want to be able to make it and store it.

Can I make up saltwater and store it in 18 litre jugs.

How many weeks or months can I store this premixed water for?

TANK SPECS:

temperature: 78°F
specific gravity: 1.023
pH: 8.0
ammonia: 0
nitrite: 0
nitrate: 20 ppm

Started adding RO salt water and live rock January 08, 2010.
45 gallon tank
53lbs fully cured live rock
60lbs of live sand
Aquaclear 70 Filter
3 Power heads
Tunze Skimmer
Current Nova Extreme Pro Light (6 – T5 Bulbs, 4 white & 2 blue)
Heater

Present corals & fish:
(1) Three headed pink tipped coral
(1) Two headed frog spawn
(2) Bubble Coral
(3) Brain Coral
(4) Neon Green Mushroom Coral
(1) Spotted Yellow Wrasse
(1) Coral Banded Shrimp
(3) Emerald Crabs

Pasfur

You would want to keep any premixed water circulating to prevent pH drops. I would suggest using a large garbage can, with a small heater inside. Then a water pump can be placed at the bottom and turned on to pump water into the display.

I must say, however, I do not see advantages in doing such large frequent water changes.