Understanding volume(s) ... and also biopellet target amount?

[Ready4Launch]

OK - first the volume question...not so much a question as a clarification of the general usage of the term.

So, to me and my mind, there's WATER volume and EMPTY PHYSICAL volume (generic tank size). When I got my tank, it was advertised as a 120gal SeaClear. Now that I have my rock and sand in place, it's obviously no longer 120gal! Duh.

Yet, on the forum and in general, when you say, "Oh, I have a 90gal tank." Are we talking generic tank size or the actual water volume you now work with?

Now, building from that, when talking about your system as a whole, do you generally include your sump volume?

More importantly, when thinking about filtration and volumes and flows and etc., do you need to use a value that is the sum of the sump and tank?

OK, so now onto biopellets ... YES! I KNOW ... GO SLOW, START SMALL!

Given that I have a 120gal empty volume + a sump that's an unknown volume (cringe!), I'd estimate that I employ maybe 90-100 gallons of water total.

What should my target -- as in final -- biopellet amount be? My initial guess is about 2 cups? I was going to start the reactor with 1/8 cup.

Sorry for the pedantic questions, but .... !!!

 

[ScottBrew]

Those are good questions! Some kit tanks call out their size by total volume of water but standard tank manufacturers call out by volume of the tank. And to further complicate things, they use the outside dimension and don't necessarily factor in glass thickness. Only way to be 100% certain is to find total volume and subtract the volume of everything inside the tank... that would require you to see how much water is displaced by putting all rock and sand in a bucket, filling said bucket with water, removing rock and sand and measuring remaining water and subtract from bucket volume.

Water volume though is easy to figure length X width X depth (in inches) divided by 231 gives you gallons.

 

[Ready4Launch]

Those are good questions! Some kit tanks call out their size by total volume of water but standard tank manufacturers call out by volume of the tank. And to further complicate things, they use the outside dimension and don't necessarily factor in glass thickness. Only way to be 100% certain is to find total volume and subtract the volume of everything inside the tank... that would require you to see how much water is displaced by putting all rock and sand in a bucket, filling said bucket with water, removing rock and sand and measuring remaining water and subtract from bucket volume.

Water volume though is easy to figure length X width X depth (in inches) divided by 231 gives you gallons.

OR ... I should have really paid attention to and counted how many 5 gallon jugs we dumped in!!

 

[ScottBrew]

OR ... I should have really paid attention to and counted how many 5 gallon jugs we dumped in!!

But was each bucket filled the exact same amount?

Figure out volume as close as possible, +or- a couple gallons

 

[Ready4Launch]

But was each bucket filled the exact same amount? [emoji14]

Figure out volume as close as possible, +or- a couple gallons

You're really trying to scramble my eggs now!!

Any thoughts on my other questions?

 

[ScottBrew]

I'm interested in the quiz here. You are looking for total volume, tank and sump.

My "90" gallon (48"X18"X25", 3/8" glass, 24" water height) tank HOLDS 84.68 gallons before any rock or sand is added. Measuring outside dimensions would give 93.50 gallons but obviously that doesn't work. My sump is a "20" gallon (24"X13"X16") with 1/4" thick plexiglass, and runs right at half full. So, that gives 10.17 gallons at normal water level. Don't forget the plumbing, holds a couple gallons as well and you can measure that if inclined, but I'm not sure the I.D. of 1" schedule 40 PVC at the moment. If you know the overall weight of the rock you could measure the displacement of one piece of it compared to the weight and then multiply by how many pounds you have. Sand, if small grain probably displaces 85% of the water its volume takes up. Rock and sand are heavier than water, water is 8.8 lbs/gal.

I think my head is starting to hurt thinking about it!

Measure the volume of each chamber of your sump, interior volume of your tank and rough estimate the rock, subtract probably 10 gallons for the rock and another 4-5 for the sand. I bet you are right about 100 gallons in the tank and then add whatever your sump holds. That should put you in the ballpark.

 

[nritter69]

Jeez, I thought I signed onto R2R not mathletes of America!! Lol. Don't over think it!!, Vertex Bio-pellets calls for 50-200 ml of pellets for 100 liters of NET SYSTEM water volume. Start at 50 ml / 100 liters. Go from there.