Question about mixing salt with RO/DI water

Litespeeds · 04/04/2006, 08:47 PM

I have heard that it is best to mix sea salt with reverse osmosis deionized water but also good to aerate it and circulate it in a holding container like a big plastic garbage can for a day or two and heat it up to your aquarium water temperature.

How important is it to do this?

I am lazy and just usually mix the salt and ro/di water and once it clears up, I poor it into my tank.

What do you think and why?

old salty · 04/04/2006, 08:58 PM

You heard correctly. The reason for letting it mix/aerate for a day is to stabilize the pH. When you first mix it, it may be a bit on the high side. Letting it stir for a day with a powerhead ensures that everything in the salt is completely dissolved and allows the pH to stabilize.

I don't heat my water, but I have a large tank and can get away with it.

Johnsteph10 · 04/04/2006, 09:17 PM

Stabilize the pH, let everything uniformly dissolve, aeration, and temperature matching all minimize the stress to your system when adding new water.

Litespeeds · 04/04/2006, 10:07 PM

Is changing 10 gallons of water going to make that much of a difference in a 90 gallon tank with about 150 lbs of live rocks and a 15 gallon fuge?

I can see if I do a major water change that I need to be more specific but do you think I can get away with being lazy for only 10 gallons every two weeks?

nemo g · 04/04/2006, 11:57 PM

other than the obvious, there is another thing to consider... salinity readings

1. if you are using a hydrometer, it is usually calibrated to a specific temperature (say 60 degrees); and since water expands and contracts at different temperatures, you will get different readings if they the new and old are not the same.

with a quality refractometer (one with atc, auto temperature correction) this is a non issue.

2. Also, "letting the salt dissolve" will give you a much more accurate reading. I have noticed that after 12 hours or so of mixing 20g or so there can be as much as .004 change after complete dissolution.

take a look at this table, itll give you an idea of how specific gravity and salt content can be affected by temperature.

http://www.algone.com/salinity.htm

in the end, does it need to be done? no. depending on the health of the inhabitants and the system a little stress will be just that, a little stress.

however, is it better? for the aforementioned reasons, it is absolutely scientifically better. and if your lazy, practical too.

you just divide the chore into two days.

1. day one, mix and prepare.

2. day two, remove and replenish

better for you, and for the tank

Litespeeds · 04/05/2006, 12:16 AM

sorry for the double post.

Litespeeds · 04/05/2006, 12:19 AM

I have several 5 gallon plastic jugs so I was planning on premixing my salt water and storing it in the jugs until I am ready for a water change. I will mix the saltwater and probably have it sit in the jugs for a week before I change my water.

I wasn't planning on mixing the salt water and immediately putting it in. As long as all the salt has dissolved into the water, do I still need to aerate it or heat it up before I put it in if it sits around for a week?

04/04/2006, 08:47 PM	#1
Litespeeds Registered Member Join Date: Jun 2004 Location: Bay Area, CA Posts: 121	Question about mixing salt with RO/DI water I have heard that it is best to mix sea salt with reverse osmosis deionized water but also good to aerate it and circulate it in a holding container like a big plastic garbage can for a day or two and heat it up to your aquarium water temperature. How important is it to do this? I am lazy and just usually mix the salt and ro/di water and once it clears up, I poor it into my tank. What do you think and why?

04/04/2006, 08:58 PM	#2
old salty Genius Join Date: Jun 2005 Location: The Island of Misfit Toys Posts: 3,131	You heard correctly. The reason for letting it mix/aerate for a day is to stabilize the pH. When you first mix it, it may be a bit on the high side. Letting it stir for a day with a powerhead ensures that everything in the salt is completely dissolved and allows the pH to stabilize. I don't heat my water, but I have a large tank and can get away with it. __________________ "The man who reads nothing at all is better educated than the man who reads nothing but newspapers." Thomas Jefferson Current Tank Info: Out of the marine aquarium hobby

04/04/2006, 09:17 PM	#3
Johnsteph10 Registered Member Join Date: Jan 2004 Location: The South Posts: 2,537	Stabilize the pH, let everything uniformly dissolve, aeration, and temperature matching all minimize the stress to your system when adding new water. __________________ John Current Tank Info: None

04/04/2006, 11:57 PM	#5
nemo g Registered Member Join Date: Feb 2006 Location: west side iz da best Posts: 1,039	other than the obvious, there is another thing to consider... salinity readings 1. if you are using a hydrometer, it is usually calibrated to a specific temperature (say 60 degrees); and since water expands and contracts at different temperatures, you will get different readings if they the new and old are not the same. with a quality refractometer (one with atc, auto temperature correction) this is a non issue. 2. Also, "letting the salt dissolve" will give you a much more accurate reading. I have noticed that after 12 hours or so of mixing 20g or so there can be as much as .004 change after complete dissolution. take a look at this table, itll give you an idea of how specific gravity and salt content can be affected by temperature. http://www.algone.com/salinity.htm in the end, does it need to be done? no. depending on the health of the inhabitants and the system a little stress will be just that, a little stress. however, is it better? for the aforementioned reasons, it is absolutely scientifically better. and if your lazy, practical too. you just divide the chore into two days. 1. day one, mix and prepare. 2. day two, remove and replenish better for you, and for the tank __________________ nG Current Tank Info: tis da bestest tank eva

04/04/2006, 10:07 PM	#4
Litespeeds Registered Member Join Date: Jun 2004 Location: Bay Area, CA Posts: 121	Is changing 10 gallons of water going to make that much of a difference in a 90 gallon tank with about 150 lbs of live rocks and a 15 gallon fuge? I can see if I do a major water change that I need to be more specific but do you think I can get away with being lazy for only 10 gallons every two weeks?

04/05/2006, 12:16 AM	#6
Litespeeds Registered Member Join Date: Jun 2004 Location: Bay Area, CA Posts: 121	sorry for the double post.

04/05/2006, 12:19 AM	#7
Litespeeds Registered Member Join Date: Jun 2004 Location: Bay Area, CA Posts: 121	I have several 5 gallon plastic jugs so I was planning on premixing my salt water and storing it in the jugs until I am ready for a water change. I will mix the saltwater and probably have it sit in the jugs for a week before I change my water. I wasn't planning on mixing the salt water and immediately putting it in. As long as all the salt has dissolved into the water, do I still need to aerate it or heat it up before I put it in if it sits around for a week?