It was more for weight distribution, you could also use them to move live rock in stead of the black bins. I definitely agree that the 10 gallons are more easily managed. 70 gallons is a lot of water to move...
It is a lot to move but to me it's just more practical. The RODI unit I have is painfully slow and there's no guarantee I'll be able to set it up right away, and the nearest fish store is 20 minutes away- either way I'll need to haul large amounts of water
A truck would be a little bit more difficult due to you needing to do more heavy lifting. If you want less lifting I recommend purchasing these 5 gallon buckets with the lids https://www.lowes.com/pd/Encore-Plastics-5-Gallon-General-Bucket/3694238.
Lucky for me, I moved all my stuff out of the old place and literally the only thing I have to do is move the tank and all the inhabitants. I plan on doing it in one swoop, however many hours that may be.I have done this move a few times with my 120g. Most recently 1.5 years ago. I have also helped many local reefers move. You want to make up as much new water as you can before the move. I mix the water in as big a container as you can find but for the actual move I use 5g buckets.
Do NOT use any of the old water once you start disturbing the sand bed even a little. And definitely give that sand a very very good rinsing before you put it in the new tank.
40g is such an easy move. I would get 12x 5g buckets. I prefer the old salt buckets as they have the rubber o-ring so no water drips out in transport. Your pickup bed will be fine for the standard home depot buckets and lids though. Just give it a good wash down after if you don't have a liner.
The coral frags I can pick off the sand bed or easily pull off the rock gets bagged or in tupperware. The rest stays on the rocks and goes in the buckets.
For any tank move I usually calculate 75% of total water volume including sump and mix up that much new water beforehand. I do it a day before and have powerheads pointed at the surface the whole time to make sure it is well oxygenated.
Day of the move I would fil 10 of your 5g buckets with 3g of the new water. I then fill some tupperware with old tank water for the frag transport.
I then pull as many corals as I can off and get them packed away.
Next step is to top off the remaining 10 buckets with 1 to 1.5g of old tank water that should still be almost crystal clear.
I then fill the extra 2 buckets with old tank water. We don't care if this water is clear or not as we use it to rinse the rock when it comes out before we put it in transport buckets.
Now you are ready for the dirty work. Pull the rock out with what ever coral is attached and give it a good swishing in one of the buckets full of old tank water. You will be amazed at the amount of waste that is stored in the crevices. Give it a second rinse in the other bucket of old tank water. Then place in one of the 10 buckets with new salt water.
Repeat this until you are down to just sand.
Empty the 2x 5g buckets that you just used to rinse the rocks and fill them with sand. Do NOT put this sand back in your tank without thoroughly rinsing until the water is totally clear. There is so much waste in that sand it can cause serious issues. There are many threads on here about tank crashes after disturbing sand bed. Most people use a garden hose ans rinse the sand with fresh water as the nitrifying bacteria housed in a sand bed is very minimal. I always keep a cup or two of old sand and rinse it with salt water in an attempt to keep the biodiversity alive but this is probably overkill probably pointless as the sand bed will surely repopulate fairly quickly with what is on the live rock. But i do it anyway because I'm crazy. I do this rinsing long after the tank has been moved and setup. I usually run the new tank a couple days bare bottom as the sand rinsing is the biggest pain and i always lack the motivation to do it after a big move.
Once you have the new water mixed up its really only a 2 hour process to break that tank down and get things packaged for the move.
I always make sure I have a couple days where I'm able to use both places but if you cant do that then the tank break down should be the last thing you do before vacating the old place and the first thing you setup at the new place to minimize the time the stuff sits in those buckets without oxygen. Longest I have let them sit in buckets is about 12 hours but I'm sure they can go longer.
Have fun.
Here is a pic of the 120g i have moved a few times. Maybe 50-60 pieces of coral and more lbs of rock than I care to think about. Never lost a piece of coral and only 1 fish died from being squished by a rock.
When we moved ours we used Lowe's and homedepot buckets with lids (they seal better than that box) we put all live rock and water into the buckets fish went into one with no Rock so they didn't get hurt. The few corals and anemones we bagged individually for transport, but put them in the buckets with air bubblers and heaters until be we're ready to put them into the tank... That work well for us, but we were only dealing with 40 gallons...
Oh and we didn't re use the sand...we were too scared after hearing all the nightmares people have delt with...we just used the caribsea live sand. But our tank is smaller, the live rock and water kept our tank pretty steady after that...we just paid close attention to it. Someone else may have different thoughts, so ask around...
I'm not going to lie, I am very jealous of your tank!!! So pretty!!!
