So, at Cats Protection we use a disinfectant called Anistel®. It has to be diluted by a ratio of of 1:100 (for the sake of pedantry, 1 part Anistel to 100 parts water). We have a 50 litre mark on our largest sink, so you had 50 litres of water and 0.5 litres (that is, 500ml) of Anistel. Simple enough so far, right?
The other day I learned that the 50l mark wasn't calculated using mathematics which is what I'd assumed, but by filling up a 10l bucket five times and marking where it got to (on the chain of the plug). In fairness, as long as you wait for the water to settle and mark it off right (both in the bucket and in the sink) it should be very accurate.
Though today I finally got round to measuring it. It was pretty interesting, I got a tape measure out and did a quick measure for ballpark figures. And the good news is, we're definitely in the right ballpark. I got
height (the marker on the chain): 10cm
The bottom's quite flat. We know this from trying to get the water out of the sink after we've used it. It doesn't drain very naturally and you often have to scrape the last bit out with your hand. On the other hand... it's a sink, it isn't intended to be dry! It's more a case of for rinsing with clean water to get the previous lot of water out. But no, I haven't actually got a spirit-level out to check how flat the bottom is and which way it leans. That would perhaps be a bit excessive. But from the pattern of the water, the water doesn't run in any direction, the plughole is raised by a few millimetres and you get a few millimetres of water at the bottom all over when you're finished.
So, let's crunch the numbers. A litre is 1000cm³. 123*47*10/1000 = 57.81
My measurements were pretty rough. I spent a lot of time on the height which is by far the most important. The others could be a centimetre out but not really more than that. If you take a centimetre off the width and the length, you get 56.12. The corners are curved which makes accurate measurements trickier. I used a cloth tape measure as well, which is not ideal, though luckily I can reach far enough to do the 123cm measure without needing someone else. If the tape measure is slightly crumpled in any way, it increases the measurement.
Is this worrying at all? Well I'd say no. using the 57.81 figure, 0.5:57.81 is a ration of 1:115.62 which isn't that far off. http://www.tristel.com/products/ani