Home /
Hydor Theo Aquarium Heater

More Views

Quick Overview

Patent pending PTC heating system to avoid damage in case of dry running. Precise temperature control. Shatter resistant glass tube protects heating element. Completely submergible.

25W – 2-7 Gallon tank
50W – 5-14 Gallon tank
100W – 14-26 Gallon tank
150W – 23-40 Gallon tank
200W – 26-53 Gallon tank
300W – 53-80 Gallon tank
400W – 80-105 Gallon tankMore

Hydor Theo Aquarium Heater

56% Recommend this to a friend (9 of 16)

16 Reviews Add Your Review

Orders over

$175

Ship Free

View Reward
Points Below What's this?

Ships tomorrow

Choose a size		Qty

25W - Hydor Theo Heater SKU: 202170 Earn 19 Reward Points	$19.99
Buy 3+ and save 6%	$18.99


50W - Hydor Theo Heater SKU: 202171 Earn 22 Reward Points	$22.99
Buy 3+ and save 5%	$21.99
Out of Stock Sign up to get notified when this product is back in stock


100W - Hydor Theo Heater SKU: 202172 Earn 23 Reward Points	$23.99
Buy 3+ and save 5%	$22.99


150W - Hydor Theo Heater SKU: 202173 Earn 24 Reward Points	$24.99
Buy 3+ and save 5%	$23.99


200W - Hydor Theo Heater SKU: 202174 Earn 25 Reward Points	$25.99
Buy 3+ and save 4%	$24.99


300W - Hydor Theo Heater SKU: 202175 Earn 29 Reward Points	$29.99
Buy 3+ and save 4%	$28.99


400W - Hydor Theo Heater SKU: 202176 Earn 32 Reward Points	$32.99
Buy 3+ and save 4%	$31.99

Summary

Total:

Please wait...

Add to Wishlist

Works as its supposed to By TROJAN on 5/8/13

TROJAN would recommend this product to a friend

I have a 50w just for my Q.Tank and have not had any issues with this brand and model so thats what im sticking with till it fails to meet the use.
Do not purchase! By Anthony on 5/5/13

Anthony wouldn't recommend this product to a friend

I have had these in the past and they did not perform well. Just recently purchased a 300W unit and after a week, it is sticking on. I like to keep my reef tank warm, but even if I drop the temp towards 70 degrees, the heater kicks on and tries to raise it around 85. I'm running LED's with a Vortech, so not much heat from equipment. House temp is 70 degrees as well.
Hit or Miss By Kathy on 3/22/13

Kathy would recommend this product to a friend

I love this heater, when it works. I have had one that has lasted over 2 years then cracked when I touched the glass one day. Woops, and another that wont turn off. I use that guy to heat my water for water changes. When it does work, it's accurate, and easy to operate. I haven't given up yet.
Not accurate By brian on 11/30/12

brian would recommend this product to a friend

Temp adjustment is not accurate in the least bit, but what heater is. I've used these for year never had a problem with them but then again I run them on a controller. I would'nt go with this heater unless you use one also.
good heater for the money By Brandon on 8/7/12

Brandon would recommend this product to a friend

this heater is obviously not the best but it works. I've had it running for about 6 months now and it still works just fine. the numbers on the dial are a little off but once I played with it enough, I got it right where i needed it. Tank runs between 78 and 80. I will probably buy another for a back up and water changes.
No good, like most inexpensive heaters By Dale on 5/23/12

Dale wouldn't recommend this product to a friend

Got 4 of these in various wattages (100 & 150) to replace some Finnex heaters that stopped working. They are compact but are very erratic, quite often sticking on. (The Finnex heaters stuck off-a little safer I'd say). Would not get again or recommend.
ok By Jason on 2/25/12

Jason wouldn't recommend this product to a friend

its a good heater for the price but when you live stock is worth so much more go and get a higher grade heater.
Good Heater By JP on 2/8/12

JP would recommend this product to a friend

I purchased this heater about a year ago, and it has been an all-around good heater for the money. I would recommend this heater to anyone looking for a budget heater that is extremely reliable.
Not my favorite By reeftank85 on 1/3/12

reeftank85 wouldn't recommend this product to a friend

I tried a couple of these 300 watt heaters, and was not that impressed. The markings on the dial are not off by several degrees. It doesnt stay consistent through the year. I keep my tank around 77 and in the summer the tank will get closer to 80, yet the heater will still kick on periodically. I plan on getting a tank controller soon and not have to worry about it though,
Not reliable By Brent on 12/29/11

Brent wouldn't recommend this product to a friend

These heaters are not accurately calibrated in my experience, which includes 3 sizes of this model. Turned all the way down (71) they heat the water to about 78 without the lights on.
Great! By Zach on 11/8/11

Zach would recommend this product to a friend

Looks great! Works great!
Don't waste your time By Weave on 11/4/11

Weave wouldn't recommend this product to a friend

I bought the 300watt for my 90g reef about a year ago. Noticed my chiller coming on alot even when we had the windows open. Looked at heater and it was on. I tried to turn it back and it just stopped doing anything. always stayed on. Thank god for the chiller or would of had a fish fry for dinner. Works good for short period of time then crapped out. Don't buy.

Write Your Own Review

You're reviewing: Hydor Theo Aquarium Heater

*How do you rate this product?

*Would you recommend this product to a friend?

Yes No
*Nickname
*Summary of Your Review
*Review

There are no videos related to this product.

Ask a Question About 'Hydor Theo Aquarium Heater'

Previously Asked Questions

No questions have been asked yet.

MODEL	LENGTH	AQUARIUM SIZE
THEO 25W	7"	2-7 Gallons
THEO 50W	7"	5-14 Gallons
THEO 100W	8.9"	14-26 Gallons
THEO 150W	12"	23-40 Gallons
THEO 200W	12"	26-53 Gallons
THEO 300W	15.5"	53-80 Gallons
THEO 400W	15.5"	80-105 Gallons

More Views

Hydor Theo Aquarium Heater

MODEL

LENGTH

AQUARIUM SIZE

Hydor Theo Aquarium Heater

BRS Reward Points