I have a cheap water pump and a long length of clear plastic hose.
The pump has suction cups so I position the pump inside the tank just above where I want the water level to be, before I start adding water back in. So at 30% for example. I use a little plastic clamp to keep the end of the hose aimed at the drain in the bathroom, and then I turn the pump on. I forget about it normally until I hear the pump starting to sound a little different. It means that the water level is almost level with the pump, so I unplug the pump and move it out of the tank so that the suction doesn't siphon anymore water out.
I have a big 50 litre bucket for water changes, I place it in the shower and fill it with water. I have a thermometer so I can match the temperature to the tank's (aquarium tank) water. I add water conditioner, and give the bucket a really good stir. Then I use the pump to pump the conditioned water in the bucket directly back into the tank. I either use a piece of aquarium sponge and a cable tie over the hose, or a piece of clean bubble wrap on the surface of the water so that the clean water flowing in doesn't mix up the sand and disturb fish/plants.
It's miles easier than buckets and bottles which I used to use. I had to find a better affordable system to make water changes less of a chore. I normally look at Pintrest or read an article while occasionally glancing at the tank so that I don't over fill it. The only hands-on part is filling the bucket with water and conditioning it.
I do water changes on my 280L, 105L and 54L this way, and it's really easy and quick.
Those are the links and prices, about €50 for the whole set up if you bought them today. I payed closer to €40 when I got them though. I chose that pump because it's strong enough to pump the water vertically up and into my 280L. This one can pump water 3 meters vertically.
Compared to the python systems available to me, it's half the price and can actually pump the water.