What are the key pieces of equipment for your aquarium

What are the most important pieces of aquarium equipment ? Decades ago, there were no heaters, air pumps, power filters/ canisters or lighting systems. The aquarists of the day maintained water quality through frequent water changes and use of plants. In today's technology filled world, what are the most essential pieces of equipment for the new hobbyist ? After the tank, should there be an investment choice between a heater or a filter ? Are lighting systems really necessary ?

I think the first purchase after a tank is an air pump.

It can power many filters and help with water circulation and airation.

Water has to move. If you are going to have one tank, then each tank needs some kind of filter. I'd make that my key piece of equipment.
Next would come lighting, as a fish you can't see isn't going to keep your interest. Plus, plants are great to grow and help with water cleanliness.
I'll take a siphon for water changes for granted - you have to have that.

And I'll go out on the line in this Internet age, and say a good general book on fishkeeping is essential. You need something to refer to for info. The net is very good, and if you can do the legwork and find a few reliable sites to replace a book, fine. But net sites tend to be superficial and incomplete, and if you have a bad idea, you will find someone else to confirm that it is brilliant. Trustworthy sources of information are essential.

Once you've done your research, then you can decide if a heater is needed, depending on your house's wintertime temperature and the needs of your fishes.

After that, there's a world of gadgets out there, depending on what you are trying to do. According to the kids I teach, replicas of Sponge Bob, Patrick and Squidward's homes are absolutely essential.

The "NO"  Tech natural aquarium.  seems to be working  

This is based purely on my experiences. When it comes to filters, I prefer sponge filters and canisters merely because if there is a short power outage while away from the house, they will start back up once the power comes back on. Most HOBs (at least the ones I have used) will not start up once the power comes back on, but instead need to be primed with water. Also, if you opt for canisters instead of sponges, it may be beneficial to keep the canister filters in a small bin of some sort, just to keep the floor from getting soaked (we learned this when cleaning one out for the first time!)! We use a small dollar store tub for each canister, works great

A used (no more money) Tim card. Great for scraping algae off glass without scratching it.

ownedbycats wrote:A used (no more money) Tim card.  Great for scraping algae off glass without scratching it.

That's exactly what I use!

I use old credit cards to scrape algae and an all-in-one plastic shovel for edging gravel, plants etc.

I think the most important investment is a good filter. Aside from water changes, the filter is the best way to maintain water quality, which is perhaps the most controllable part of the aquarium that we can manage.

Heater or lighting systems are important but rank secondary to filtration, and I definitely skimp on the heaters and lights when I can, though I am not a plant aquarists. I think plant keepers place more emphasis on lighting for obvious reasons, and then filtration and heating are in reverse rank.

I am a small tank aquarist so I prefer hang on back (HOB) filters and the larger the better. I do like canisters however they are preferred for larger systems, which are larger than the "nanos" that I keep. For my small fish, with smaller bio loads, I am good with the HOB filtration. For larger fish, and larger tanks, I would strongly prefer the canisters or even a dual system canister and backup HOB.

Backup filtration systems are critical when you keep high value fish, but most systems are more than suited to one filter.

As mentioned, biologic filtration is the cornerstone of water quality. If you desire mechanical and chemical filtration, a more complex filtration system is in order.

I'd like to point out that not all HOBs need repriming if the power goes off. I have a RENA HOB and it only needs repriming if the water level in the tank drops a lot. Otherwise, it stops running, but there is still enough water in the filter to completely cover the motor and then some so the pump can safely restart when the power comes on.
This does depend on the design of the filter so you need to do some research before buying if your power goes out a lot.

I think the best investment in equipment is a good filter. I always step up the size too, some filters may be advertised as being good for 30 gallons, or 10 gallons, or 50 gallons, but it is often really a bare minimum at best. You really can't overfilter.

My most important piece of equipment is my deep freeze.  

That' right my deep freeze,

When I am bent over the laundry tub cleaning fish filters(my favorite past time), I need a place to lay my beer. It had to be instantly accessible, so I can grab a quick swally without having to stop and leave the sink.

Best money I ever spent.

Steve