I soon found out there are specialised articles on the market for these types of tanks, but also that they are well overpriced. I decided to use some of the leftovers to build a DIY Gravel Cleaner after the idea of JBL, found here. (Nice thing about it is that it is square so it can reach the corners of the tank easily)
This article is based on my blogpost on http://hmf-shrimptank.blogspot.com, where I also post the entire DIY project for building a filter for my shrimp-aquarium. Comments and feedback are welcome!
Here are the steps I took:
Step 1: Ingredients
Some tubing of roughly the same diameter
Have some tie-wraps and teflon-tape or plumbers-tape ready
Take a small (transparent) square container left over after the contents have run out. I used a soap-container in my example. I would not recommend to use something that stored any more serious chemicals
Clean out the container REALLY thoroughly as shrimps will die if you don't!!!
Step 2: Building
Bend the PVC pipe in a 90 degree angle to form an L-shape, such that it feeds the hose away from the aquarium. Bend the pipe easily by pouring hot water over it
Insert the PVC pipe into the fill-cap of the container. If it doesn't fit, use the plumbers-tape to create a tight fit and secure it with a tie-wrap
Fit the hose over the other end of the PVC tube by heating it in hot water, lubricating it with some soap and stretching it over the PVC pipe. Cool it down in order to quickly reshrink it and secure it with a tie-wrap
Do some cleaning again to make sure any leftovers of soap are gone!