Reddit mentions of Hydor ETH 300 In-Line External Aquarium Heater, 300w, 5/8" hose

Well, I have a planted tropical 75G myself with black sand and small rock substrate. I use a Fluval 406 which does great work keeping the tank clean and never encounters any sand problems. Besides being absolutely silent, it's a really great canister for cleaning and customizing your filter media. I have a moderate bio-load and it handles it easily with a bit to spare. I keep the temp steady with one of these heaters which keeps the water a constant, unwavering temperature. I also hate HOB filters and tank clutter in general, so that was a great choice for me. The result isn't too bad I think.

I'm a Hydor girl myself; got their 300W in-line heater to go with my Hydor 350 canister filter; perfect temperature regulation and added bonus that it's outside of the tank!

Pretty much every submersible heater review I've seen on Amazon included multiple stories about water getting in and frying someone's fish. Hydor was no exception.

That said, Amazon reviewers gave the highest reviews (I included number of reviews in my assessment) to the Aquatop Quartz Glass Submersible Heater and the Aqueon Submersible Aquarium Heater. I'd go with the 150W (up to 40g) for both.

I'd personally go for the Aqueon here because I like the dial better. Hope this helps. Good luck!

I'll check it out! I like the idea of DIY but thankfully money isn't really an object when it comes to my build. I think i'd rather get a nice looking canister and have it on display a bit. I was thinking of getting possibly a hydor inline heater
With a Fluval G3.

yeah.. considering this down the road

Fair warning, incoming essay haha

27 gallons is perfectly fine. The first thing you will want to read up on is the nitrogen cycle and fishless cycling. The best way to cycle your tank is to ask a local fish or pet store if they can give you some used filter media to jump start your cycle. If not, buy an API test kit and follow the steps in those guides then your tank will cycle in about a month.

For filters you have two main options Hang off the back (HOB) or canister. HOB are easy to maintain and clean which seems great as a beginner. They need to be cleaned every couple-few weeks. Aquaclear are great HOBs. For your size tank I would get an aquaclear 50 or two of the 20/30s (one for each side).

I prefer canister filters. They give you more options for customization, can hold more media, and don't need to be cleaned as often as HOB. Buuuut they typically come at a steeper price. The most popular brands are eheim, fluval, and sunsun. I have eheims and love them. Reviews for sunsuns can be hit or miss, but they definitely have good value for their price. When picking a filter you generally want a turnover rate of 8-10 times your tank size. So 27 gallon tank, youd want about 216 - 270 gallons per hour (gph), keep this in mind when picking a canister.

If you plan on tropical fish you will definitely need a heater. Aqueon pro and eheim make good heaters. If you go canister, you can get an inline heater which are nice because you don't have to look at it or try to hide it in your aquarium.

For planted tanks you need a substrate. The cheapest option is to use pool filter sand along with some root tabs. Look into the walstad method if you wanna keep it low tech and cheap. The only problem with this method is that if you ever want to move plants or hardscape around it can be a bit messy. The more expensive route is to buy some aquasoil. There are a few types, but the most well known is ADA aquasoil. These substrates are packed with nutrients that last at least a couple years usually. In between is to use a porous substrate like Fluorite or eco-complete. These come with a little nutrients, but will need fertilizers to continue its benefit.

Fertilizers area great way to keep your plants happy and healthy, but for many plants are not really necessary. If you decide to use them you can buy them in liquid or dry form. I suggest buying dry because it is much cheaper, but you will have to figure out how much you need to dose. Luckily there are calculators out there that can do it for us!

Lighting you have many options. My favorite are finnex LEDs. They are middle of the ground pricing wise and do their job very well in my experience. Here is a good guide for lighting. When researching a light you want to use you should do so by finding its PAR value at the level of your substrate. Low is about 0-30 PAR, medium 30-50, and high 50+ PAR. Low you don't need pressurized CO2 to avoid algae, medium it is recommended, but you can get away with a densely planted aquarium and use of seachem excel, and high you need pressurized CO2.

I like to use hardscape in my aquariums. Things like rock and drift wood give a natural appearance to aquariums, provide shelter for livestock and take up space. If you get into aquascpaing, hardscape plays a major role.

Plant selection will depend on your lighting, fertilizer, and CO2. Here is a list of good low light/low tech plants. If you want more demanding plants do your research and ask questions if you have them!

Fish selection depends on you and what you like. See a fish you're interested in? Do NOT automatically trust a sales man at a petshop or fish store. Do your own research on the fish before buying and ask questions about people's experience with the fish and its compatibility with your tank. In a 27 gallon you can fit 1, maybe 2, groups of most smaller schooling fish and then some bottom feeders.

A general stocking plan would be 10-12 of a schooling fish like neon tetra (or something of that size), 10 salt and pepper cories, 6 otocinclus, and some red cherry shrimp.

The most important advice I can give you is to do your research. Doing your research will save you time and money. People are generally friendly and helpful on this subreddit so don't be afraid to ask more questions.

I've had one of these for 2 years with no issues at all. The Amazon ratings tend to agree as well. https://www.amazon.com/Hydor--Line-External-Aquarium-Heater/dp/B0002Z7VQE/ref=sr_1_1?ie=UTF8&qid=1473222391&sr=8-1&keywords=aquarium+in+line+heater
In the winter I throw an submersible heater in just to be safe.

Haha, yeah I can't believe I had forgotten about Inkbird. Talk about a brain fart.

It's probably too big of a heater. However, it was the ONLY in-line heater on the market and at the time, I was under strict aesthetic requirements in regards to my tank. (Roommate just didn't want something looking messy). Thus, in-line heater it was. If you're curious, this is the offending heater.

Where I live it gets juuust cold enough that the fish need a heater. The heater I have right now is working fine, but if I can go back to in-line someday, I really would if I can be certain that it can't kill off my tank again. It really was amazing while it didn't bring upon the fiery Apocalypse.

Just get a canister filter with an inline heater like this one. It's what I did and it works fine. Not sure you need an air pump.