How can you get EXACT water volume?

[mike550]

Dosing.
That and anything that may come up in the future where knowing the ACTUAL total water volume will prove to be useful.

So that’s really interesting. But even if you knew volume exactly at any given point in time won’t you still have volume variability given evaporation and precision of your ATO? Also, isn’t the dosing amount affected by consumption which itself is affected by a bunch of other variables?

Not criticizing. Just asking questions looking to better understand

 

[Dj City]

Roughly, you're going to want a mixing tank to hold a decent water change of at least 20% / 40g.
I'm not advocating a mixing 'station', just a drum or such to make new water.
What are your plans?

There will be no water changes on the 180 gallon.
Only water change will be an emergency water change if needed.

 

[Dj City]

So that’s really interesting. But even if you knew volume exactly at any given point in time won’t you still have volume variability given evaporation and precision of your ATO? Also, isn’t the dosing amount affected by consumption which itself is affected by a bunch of other variables?

Not criticizing. Just asking questions looking to better understand

The amount dosed is based on consumption if dosing elements.
Meds or something other requires knowing actual water volume.
Even dosing elements, you need to know water volume or you will be wildly off.

Evaporation should not affect the water volume too much if you have an ato.

 

[ca1ore]

You can figure it out easily enough. The first step is to measure the INSIDE dimensions of the tank. Most manufacturers claim tank size based on external dimensions which overstates the actual volume .... sometimes significantly. My current tank by convention would be 450, yet it actually only holds 400 gallons of water. Then fill the tank 3/4, mark that point; add your sand and rock and measure the water level rise. That’s the displacement you’ll have to subtract. So, internal width x internal length x final water height (in inches) all divided by 231 gives you gallons. Then subtract the displacement and you’ve got a good estimate for net volume. Sump is easier because there’s very little displacement.

 

[Greg P]

So that’s really interesting. But even if you knew volume exactly at any given point in time won’t you still have volume variability given evaporation and precision of your ATO? Also, isn’t the dosing amount affected by consumption which itself is affected by a bunch of other variables?

Not criticizing. Just asking questions looking to better understand

With an ATO, water volume is pretty precise. My 115g system uses about 250mls/hr of RO.
If I test my water before the ATO runs, the variance between 435,275mls system volume and the next run of the ATO adding 250mls is pretty tiny. Only about, what say, 0.0005%
Nothing to worry about when dosing.
If you run a 10g tank and your ATO doses 250mls/hr, your change is still only about 0.006%. Not enough to worry about.

There will be no water changes on the 180 gallon.
Only water change will be an emergency water change if needed.

So what are you planning to use during an emergency waterchange?
This could be what you use to measure how much your system holds.

 

[Dj City]

So what are you planning to use during an emergency waterchange?
This could be what you use to measure how much your system holds.

I'm still trying to work out what I would do for an emergency water change.
I have two 32 (I think) gallon brute trash bins but I will have nowhere to store them unless I get VERY creative on my rear deck.
I live in Maryland so I get both COLD winters and HOT summers.
I don't know if a heater would keep 32 gallons of saltwater at temp when it's 20° outside.
Summertime there is nothing I can do to keep water cool enough to use.

 

[Greg P]

OK, so measure out one of those brute cans with tapwater and use it to do your initial tank fill for both an accurate system measure and also a system test for leaks/noise etc.

 

[Greg P]

Then you can use the same brute can to mix fresh saltwater to fill the system. What saltwater you remove while adding sand/rock etc can be subtracted from your total system volume.

 

[Greg P]

Just be sure you use something accurate to mark out the brute to start with.
It should be the only time you need to do so.

 

[Greg P]

Items you'll need in the future for accurately measuring dosing will include a very reliable beaker/measuring cup of some kind. Not something from Walmart. So this item will not be a waste of money to only fill your tank one time.

 

[phatduckk]

When I started I bought a 40 gallon brute and two 20 gallon Brutes. I filled each 5 gallons at a time and marked the can each time I dumped in 5g. When filling my system I was able to keep track nearly exactly how much water it took.