SG Math

[jrs24]

I'm not a math major or anything so its a little difficult for me but i just dont think I'm figuring out the SG right for my new tank
1.005 SG is what I'm going for (New Puffer)

1 cup of salt can raise 5 gallons of water .05
8 cups of salt to raise 20 gallons to .1
1*.01 = 10
8 cups 10 times to get SG to = 1

80 cups to raise 20 gallons to 1

[Boxermom]

If its an existing tank, shouldn't raise it more than .002 per week.

[jrs24]

its not an existing tank and im not really planning on dumping 80 cups in at once but i was just wondering if it is in fact 80 cups that i'll need

[Boxermom]

Somehow I doubt it. The way I'd go about figuring it us using a refractometer and figuring out how much it takes to get 5 gallons to wherever I want it, then multiply that by 4 to get 20 gallons to that point.

[Pufferpunk]

Why would you want to raise the SG to 1?

That estimate of "1 cup of salt/5g raises the SG .005", is a very rough one & depends on the brand of salt & whether it's been exposed to air/water or not.

[jrs24]

its hypothetical im trying to understand the math and how to calculate it...

[Pufferpunk]

Gotcha!

[jake_vdb]

I'm not a math major or anything so its a little difficult for me but i just dont think I'm figuring out the SG right for my new tank
1.005 SG is what I'm going for (New Puffer)

1 cup of salt can raise 5 gallons of water .05
8 cups of salt to raise 20 gallons to .1
1*.01 = 10
8 cups 10 times to get SG to = 1

80 cups to raise 20 gallons to 1

Water without any salt is 1.000

You want to raise it to 1.005

You only need ~1 cup per 5 gallon bucket. So ~4 cups of salt for a 20 gallon tank

[Pufferpunk]

What about substrate & decor?

[Fella]

http://homepage.mac.com/nmonks/software/software.html

I'm sure Nmonks won't mind me linking to his brack calc software, which can work it out for you

[jake_vdb]

What about substrate & decor?

should've said 20 gallons of water, not 20 gallon tank

[jrs24]

i see i knew it was messed up =) thanks for straitening it out

[ChesapeakeSwellfish]

Aquarists use SG to infer salinity - by convention because old floating hydrometers were the way we measured long ago.

Biologists measure salinity directly in ppt. - parts per thousand. I'm convinced this is more logical and the math errors would be fewer.

Refratometers almost always have scales for both SG and PPT. If just starting out, start thinking in PPT, and knowing that full-strength SW is 35 ppt, you can see how easy it is to work with the ppt scale.

[jake_vdb]

You only need ~1 cup per 5 gallon bucket.

Thought I would post an update. When I did water changes today I took close measure of how much salt I was using. I filled a 5 gallon home depot bucket with water (stopping only about an inch from the top of the bucket). It took 2/3 cup of instant ocean to achieve 1.005 SG.

I also calibrated my refractometer with RO water just before doing the test, and mixed the instant ocean using a powerhead in the bucket for around 15 minutes. I'm pretty sure the salt was completely dissolved.

[ChesapeakeSwellfish]

I allow salt to mix overnight at minimum.

When you did water change, was new water temp same as tank temp?