Discussion in 'Water Chemistry' started by Seabeast, Sep 8, 2009.
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just curious why do you want to lower it?
Sorry i have a refractometer thats what i had to calibrate. If you guys think i should just keep it there then i will.
1.024 is pretty good, I keep mine at 1.026.
Alright thanks man
I keep mine in the middle 1.025 rule of thumb is 1.024-1.026 unless you have a speficic reason for a different sg level.
I'm not reading the whole thread. Please forgive me if someone has already said below ...
Just wanted to say to make sure i) you're testing consistently and ii) using an accurate test.
I've gone to the glass floating thingies. Got tired of the plastic ones where a tiny little bubble that you cannot see messes up the reading.
the loss of fresh water
Got curious about how much water evaporation it would take to go from a specific gravity of 1.023 to 1.026.
So did a quick calculation, without thinking, please everyone double check me. I'm ignoring adding the volume of salt back into the equation just cause I'm not that patient, or interested. I'll let you all do the checking and thinking for me please, hehe.
if at 74F
1.026 is 35.9ppt salts
1.023 is 31.9ppt
then for a 100 gallon system at 1.023 the initial volume before evap is 100, and the salts are 'x'
x / 100 = 0.0319
i could have multiplied 100 by 8 pounds per gallon to be more valid, but wouldn't it divide back out at the end anyway? if it bothers anyone, just replace the words 'gallon' with 'pound' and 'volume' with 'weight' and continue.
after evaporation the remaining volume is 'z'
x / z = 0.0359
x = 3.19
z = 88.9
loss of 100 - 88.9 = 11 percent evap
thus it would take about 11% evaporation of water to go from 1.023 to 1.026.
if anyone wants to refine or correct mistakes, please feel free. won't hurt my feelings. i'm not married to it. just goofing around.
Just a note,the glass floaty things arent that great either,relying on one of them is what caused all of my crabs to die.
You won't get an argument from me. I've got two of them and if one reads 1.023 then the other will read 1.025
But the plastic thingies? Forget it. They're even worse.
However, once I settle on using one of the glass thingies, I do find that they are farily reproducible, if not accurate. The one will always read 1.023 and the other always 1.025.
So I'm pretty happy that I have an accurate test once I've found a good copy. Or, I can correct (e.g. subtract 0.002 off of the one that reads high).
But I'm talking about the big glass thingies, not the little bitty ones.
One of the risks about the big glass thingies is if I accidently break it in my tank.
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