Re: PPS, or EI? or something else?
If you are starting a tank from zero you will have many issues because of irregular water changes. One way around that is to setup a moss only tank with no light or very little light and no CO2. Works every single time. You can do tanks similar to these with only moss:
http://neatorama.cachefly.net/images/2008-02/nature-aquarium-1.jpg
http://www.adaaust.com.au/gallery/contest2005/thumb/foto_01_05.jpg
http://www.youkosoitalia.net/wp-content/uploads/2008/06/10.jpg
http://www.aquabird.com.vn/home/images/news/News_36pj.jpg
You get the idea...
If you are not just lazy but also patient then there is an alternative to EI and PPS!
The general idea is very simple. You just let things go their way and use the light as a way to control things. This is how:
1. Put as many plant as you can in the tank (and don't be foolish - use Aquasoil as substrate).
2. Install a strong light on a timer (2+ wpg). Run the light only 2-3 hours a day (the rest is darkness or very low light).
3. Have CO2 running 24/7 (turning it off throws the entire system up and down - inconsistency is the main problem in planted tanks). Also with a very short light period the CO2 literally keeps certain plants alive. Without it they will melt in one (dark) day.
4. Don't have time/willpower to do water changes? How about getting a plastic pitcher - dip it in the tank and replace 2-3 quarts of water every single day? It will take less than 60 seconds. Too lazy/tired to do that? No problem it's no big deal really if you keep 1-3 as described. But your chances of making a mess of the tank increase.
6. After the first week, once a week add about 1/4 teaspoon of Potassium (for a tank 20-75 gallons).
7. After the first month add 1/4 teaspoon of Calcium and 1/4 teaspoon Magnesium (unless your tap water has them in good amounts of course).
8. After the second month - Iron/Traces, Nitrate, Phosphate - a pinch of each once/twice a week.
9. After month 2 you can start increasing the light period - add 30 min every week - until you get it as long as you wish.
The short light period with strong light AND the consistend CO2 will do the magic. Don't preocupy yourself with adding exactly 1/4 teaspoon of this or that, I just gave a good measure, it can be a little less or a little more.
That way you will ALWAYS end up with a tank that is so stable that you can let it evaporate 30% with no issues whatsoever. You can stop fertilzing completely. You can overfeed or underfeed the fish. Never an issue except a little algae on the glass.
My advice is proven but I don't push it because people are impatient, want to tinker with numbers, water changes, tests, and all that cool stuff. If you read what Takashi Amano suggests about starting a tank you will see that it's very much what I just described except I'm easy on the water changes, and I add Ca and Mg.
--Nikolay