Electrolyzer produces less oxygen and hydrogen then expected.

There are electrolyzer setups that are self-powered. 1 electrolyzer with 2 pumps left and right of it isn't. Wiki has some examples of how to accomplice a self-powering  setup.

Even if you have the perfect configuration to not lose any gas the electrolyzer produces (if there is too much gas the electrolyzer stops working, if gas isn't sorted fast enough before new gas is produced from the electrolyzer, there is a chance some gas gets deleted), 1 electrolyser can power 1 hydrogen generator (meaning 800w), not 2 generators.

If you constantly powering 2 pumps, the electrolyzer and 2 filters that adds up to 840w, ignoring the liquid pump that isn't constantly working but still needs some power too every now and then.
 

Yep, it happens that way, so i come with 3 by 6 space. There is at least one thread on that deleting issue, but i no idea how to find it quickly. most important i got - better to keep tile above left upper tile of electrolizer not occupied by something other than gas, prefferably hydrogen

 

@sakura_sk you're right about 840 watts consumed with regular filters, but even using them there is enough hydrogen to generate 896 watts, also there is possibilty to lower filtering loses, even to complete zero with mechanical filters(but i tend not use them)