When you add water to your pool, you also add dissolved calcium (and magnesium) carbonate. Adding hard water means adding a lot calcium carbonate. Water evaporates, the calcium carbonate, dissolved in it, does not. Your pool water gets harder and harder. In time there will be a point where there is simply too much calcium […]

This article allows you to make disinfectant yourself. Clean hands are one of the keys to not getting infected with COVID-19. What to do if you can’t get disinfectants like water and soap when you are on the way and alcohol based disinfectants are sold out? How do you make hand sanitizers yourself? There are […]

A page with substantiated pool facts, explanations and instructions without commercial interests. I could not find it on the internet and that is why I made this page. This page is intended to get a quick and good view of facets of swimming pool management, to reduce costs and to keep health aspects optimal. This […]

In general, minimal design is overvalued – contrary to rich design 😉 This is especially true for desktop environments with a multitude of controls. It does not mean that minimal design is always bad, read on. In this evaluation I use “Napoleon in St. Helena”, better known as “Freecell”. Here is a somewhat scientific but […]

A client, working in health care, had a special request: each working day she was filling in forms in a database with patient data. After the day was finished she wanted a back-up. In general, a back-up of an in use database is a bad idea. She was using Windows with a custom database application. […]

These are short notes for copy+paste. Polylang I use both English and Dutch for posts. Post that are read often will be translated. Otherwise, automatic translation is an option. So I create one page per language, start writing in one page while pasting the code below in the other page, renaming the URL. Do keep […]

See: https://vanderworp.org/nl/lassen-aantekeningen/ (or automatic translation).