I have multiple tanks, sumps, refugiums, and filters in my system with unknown amounts of live rock and sand. I was wondering if anyone knew of a formula I could use to know how much water I have in my system besides LxWxH. Maybe something like x amount of RO water will lower x amount of water x specific gravity. Anyone know any such formulas or have any other way to find out system volume?
True system volume.
- Thread starter FRED0
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AcroporAddict
There is no substitute.
What you can do is mix up a volume of salt water, 10 gallons, for example, that has an identical SG as your system. Then record the volume of RO water it takes to dilute the 10 gallon sample to your target SG. Then dilute your system SG to the same target SG. Take the total volume of RO needed to dilute your system SG to the target SG and divide by the volume of RO needed to dilute your 10 gallon sample to the target SG, and multiply that number by 10 gallons, and that should get you your total system volume.
There may be a certain margin of error, but it should get you fairly close. I would just make sure to use a high quality refractometer.
There may be a certain margin of error, but it should get you fairly close. I would just make sure to use a high quality refractometer.
What do you need the number for?
Unless you are willing to change the sg a lot, or use a conductivity meter or unusual refractometer, that sort of calculation will be too uncertain to be much better than l x w x h minus a correction for stuff in the water. Most refractometers are, at best, good to about +/- 5%.
Unless you are willing to change the sg a lot, or use a conductivity meter or unusual refractometer, that sort of calculation will be too uncertain to be much better than l x w x h minus a correction for stuff in the water. Most refractometers are, at best, good to about +/- 5%.
AcroporAddict
There is no substitute.
Most of the guides for calculating net volume I am familiar with say to take the L x W x H like you state for sumps and anything else that holds water besides the tank. For the tank L x W x H minus 20% for the rock and sand. That is what I use for my own system.
The SG route was what the op was looking for. I couldn't think of another way to do it using SG like the OP wanted other than to get a standard for a specific water volume SG change, then apply the same standard to a change in his system volume.
Yes, if I had to do it, that's what I would do. Get a good conductivity meter, then add about 5% of the estimated volume in RO/DI and monitor the conductivity drop.
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