america ist much more known for pools and spas than germany. Outdoor-pools have been very exotic in germany for a long time. This has changed over the last 7-10 years. In the meanwhile you can by e.g. intex and bestway-pools in german discounters, like aldi and lidl. Even if you can't believe, we have very warm summers in germany, too. My pool temp. last year between June and September was around 25-28°C. with only 5,2 m² of sun collectors. I have an inground-pool, round, 4,5 diam., 1,5 m. deep.
I learned, there are many differences between the american and german way of running a pool. Maybe you are interested in reading, how I run my pool.
The intex and bestway pool-sets are delivered with small cartridge filters, which are very weak and not able, to run a pool properly. Because of this, many people are of the opinion, cartridge filters are bad. That's wrong of course, but it is the reason, why in general sand-filters are being used much more in germany.
Prof. cartridge filters, like hayward, StaRite etc. are highly efficient, but cartridge replacement is very expensive and the cleaning takes a lot of time. Sand filters are backwashed quickly once a week for 3-5 minutes and the filtration-media can be run for several years. So we add approx. 500-700 litres of fresh water every week. Until 3-4 years ago, sand was the more or less only known filter media in germany. Then glas media came up. Many people I know changed from sand to crushed glas (AFM / EGFM) or glas-bubbels 0,5-1,0 mm diam.
The best known sanitizer is chlorine, manually added or SWG. Since 2-3 years many people switched to anorg. chlorine (e.g. HTH-shock, HTH-briquettes <what I use>, appprox. 10 of 7g. Tbl. with warm weather every day). The problems being caused ba cyanuric-acid is highly discussed in german pool-forums.
Some people use stabilizer (cyanuric acid) to 20-30 ppm., but most don't use it. I don't have cya in my water as well.
Chlorine levels in german pools are recommended between 0,3-0,6 ppm. That's the reason, why people, who do not know so much about running a popl and the effects of cyanuric-acid, have problems with green water and alga, because with a level of 40 ppm. cya around 50 % of chlorine ist not free to sanitize. Most people I know, run their pool with 1-2 free chlorine und do a chlorine shock of 3-6 ppm. once a month.
In germany we run our pools with a pH between 6,8 and 7,2, because that's the range, chlorine works best. Very often I read, you in america run a pool with a pH level between 7,4-7,8. Why do you da that, what's the reason?
Some people here use anti-alga, some don't. I use it once a week (quateräre-Ammoniumverbindung). Agents like copper-sulfate or silver-ions are rarely used, because they highly harm our nature.
Although I don't use SWC I added sea-salt to my water (23.000 litres/75 kg. salt). My father and I are suffering from neurodermitis and like salt water very much. The skin feels smouth and not dryed-out.
I'm looking forward to "awaking" my pool this weekend!
Marcus because my pool is one of my biggest hobbies.
ps: hope my english is not too bad