I will be using 4-5L of the betta dirty water next friday and the sponges will be 1 from the betta tank and 1 from the fish tank.
The tank is 47cm wide, 25cm front to back, 29cm tall closed (72cm with the top flipped up). There is a nicely fitting clear plastic cover between the light and the water but that is very tricky to remove UNLESS you flip the light upwards so you need the clearance above and the same goes for feeding as it is quite a tight fitting top it would be easier to remove the top cover, but you may be able to lift the plastic cover (fiddly but light weight to drop food in?). With that top removed access is good from the open top. Of course, flipping the light up means there is no light when doing maintenance, unless you drop the light back into place which I do but I do have unusually skinny arms and unless you have really fat arms this should work.
I like black backgrounds so just used a refuse sack which I taped on and that works well because you can also wrap it around the back section of the sides - this may make more sense when the tank is in front of you.
I wouldn't even consider moving it when water is in it for maintenance, bad idea in general and I am not sure it would take too much of that sort of stress....................
The dripper sits nicely on the top and the water pipe can be squished between the top and edge of the tank which holds it securely so won't spring out when your not looking.
Overall it is a great tank and ideal for shrimps (or Betta) as it isn't too tall, which is wasted space for shrimps lets be honest (or Betta), you want more base area than height. It is easy to set up, well there isn't really any? If you decide which way you want the top to flip before you set it up as the front is the same as the back (though actually I don't know which is which) so you just turn it round the other way. 3L of substrate gives about 3cm depth which looks about right. Although it is officially a 25L tank, mine holds 20L of water (assuming my measuring jug is accurate and once all the stuff is inside and allowing 1.5 cm from the surface for safety and air etc.
The only 2 'possible' draw backs are you NEED clearance of 72cm from base to flip the top up, which you are going to have to do regularly in reality. The second is the horrible box section that is built inside to house the filter and heater, it wastes way too much room and looks hideous, but that can be removed as I have done using this video (it's in german but you can see what you need to do and I actually used a sharp bread knife as I don't have any of the blades she uses https://www.youtube.com/watch?v=odw-rgejNgg. The filter that comes with it is shrimp safe and adjustable for flow rate and angle.
I think I have covered as much as I can think of but let me know if you want any other clarification on anything?
Thanks for that. I put the substrate in the tank and I think that is exactly the depth. I need to add more water as only 6L in there at the moment but it does look too much soil to my eyes at the moment but that's probably just because I only had half that before and I just need to get used to it like that. I will half fill the tank (hopefully get that done today) ready to start putting the plants and decorations back in and then decide, but it is a great help to know that that is the depth others use and works ok!
Thanks again shrimp the world.