Finnex Max-300 Heater Controller Review

I’ve added a Finnex Max-300 Heater Controller to my 75 Planted Aquarium after a new heater malfunctioned. The additional peace of mind is worth every penny of the $30 investment. Considering we put significant amounts of money into our aquariums, what’s another $30 to protect our fish, shrimp and plants? So far, I’ve had this heater controller for 2 weeks and it is functioning flawlessly. I am very happy with my purchase and will be adding this as standard equipment to future aquariums.


In the Video I incorrectly stated I paid $35 for this item. After checking my order info on Amazon, it was $30, which makes it even a better investment.

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PlantedMN says:

Correct, UNLESS my heater malfunctioned too. You just need to set the heater temp higher than the Heater Controller temp. I could lower it to 78 or 79, but you get the idea.

PlantedMN says:

The Manufacturer claims it is not compatible with Aqueon Pro heaters. Not sure I understand why that is.

PlantedMN says:

Thanks. I would recommend this for any aquarium. All the heaters seem to be so cheaply made these days.

jeremiemcd says:

Nice tank bro great job.:)

PlantedMN says:

Yes, I’ve never had a heater stick before. For the price you can’t go wrong. I feel much better knowing my fish are safe.

PlantedMN says:

That is correct. Hygrophila Polysperma ‘sunset’.

Samson Vang says:

Nice little gadget. happen to be in minnesota?

Fish & Fishing says:

PS. What is that plant near the heater? Is that Hygrophlia polysperma AKA Tropic Sunset?

nightgoblinshaman says:

Excellent review on the Finnex Max-300. It is definitely something I will purchase for that added piece of mind. Probably a stupid question, but will it work with any heater?

Robert Rainey says:

Hi, I am shopping for a heater controller and your review helped me. I’m two years late for your post but this item currently looks like it is still one of the better ones out there. How is the accuracy per degree, some say its off 2 degrees? I have saltwater and want less fluctuation as possible in the water temp. Thanks for the video 🙂

PlantedMN says:

This is a 75 gallon. Thanks for watching.

Fish & Fishing says:

I guess my next question would be where did you get it. I cant find it anywhere, last I checked it was not being sold in the states.

Jorden Watkins says:

I just ordered one along with the finnex titanium heater. I’m so sick of check heaters I have no piece of mind unless I check the temp several times a day in my reef. I’m really looking forward to having that! Great vid thanks

akalegs says:

Great review and explanation.

Eric Stephens says:

Don’t buy finnex the controllers suck!

PlantedMN says:

Thanks. Its turning into an over grown jungle.

Fish & Fishing says:

Man I really wish I didn’t see this video now I have to get one lol. Great Vid you hit the nail on the head when you spoke about the the amount of money we invest in the tanks. Makes since to have that added protect.

Golden State Warriors Fan says:

I own the Fluval e series 100 watts i have it set 80 and the Finnex MAX-300 set at 78 the red heating light on the controller does not come on should i turn it up to 79 on the controller ??

NickMach007 says:

Great review. I have been looking into these. For any DIY-types out there not afraid to play with a bit of electricity you can make one of these yourself. Just google, stc-1000
Tank is still looking great by the way.

Rico Suave says:

Beastmodeeee damn i want one for security reasons also

NickMach007 says:

I just started up my own channel, and I was thinking of this video. I just posted my first video where I built a DIY version of this for about the same price– but it is more customizable and I put a fuse in mine that way if the heater does malfunction, it won’t burn out the microcomputer. Anyhow I’ve been a fan of your channel for awhile. Would love it if you could watch my video and give me any feedback. Thanks!

fishtankpro2000 says:

nice tank I love it how big is the tank

njw1383 says:

That heater controller looks an interesting gadget. I’ve never seen one of those before.

PlantedMN says:


ADU Aquascaping says:

Great explanation. You need to have them pay you money for that… lol That is a great idea, I need one of these. So if the controller malfunctioned it wouldn’t go higher than 80 degrees?

Larry Liotta says:

Wow just got one works great. Thankyou

Benjamin Liker says:

subbed! sb?

Warren Wilson says:

Absolute garbage controllers AND heaters. Yes, they are cheap, but are you willing to be cheap on a heater which very well might cause the complete destruction of your tank?  Reef Central, Nano-reef, Reef Frontiers, Planted-Tank….etc etc etc have numerous reviews by people who had their tanks destroyed. The information is out there and being cheap with one of their heaters might very well cost you more money in the long run.

Marie-Michèle Tremblay says:

I don’t see well a 2:14, but is it an electric plug that you can plug your heater in? A bit like a power cord?

Pinkymeister says:

Do you know if this heater works with the hydor ETH inline heaters?

Brian's Fish Tanks says:

Good idea. Never heard of these before. I’ll be adding these to my tanks…

PlantedMN says:


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