Marina Floating Thermometer with Suction Cup

Featured:

• Easy-to-read floating thermometer with suction cups 
• Includes a safety zone indicator 
• Equipped with suction cups 
• Ensures your aquarium is at a proper temperature 
• 4.25 inches tall

Description: 
The Marina Floating Thermometer is the perfect way to make sure the water temperature in your aquarium is just right for all your fish friends! The thermometer is easy to read and has a safety zone indicator for most tropical fish, so you know that temperature is just right for your fish. The Marina Floating Thermometer is equipped with suction cups so it will stay stuck on your aquarium at all times.
Price: $1.99

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Reviews: 

 So this thermometer comes with the suction cup. It's supposed to be able to stick inside the tank, underwater so that it can accurately read the water temperature. I stuck my thermometer in first, and then added the water (it only seemed logical). I've had it for three days, and so far it has been sturdy. My betta even nudges it sometimes and it does not budge. My only issue with it is that the numbers for the temperatures are between two longer lines, which makes it a little confusing as to what temperature the water is. It would really help if they made that a little clearer. On the plus side the thermometer does have a range of temperatures that are perceived to be optimal for fish, which is highlighted in green. Because of this I am giving the product 5 stars. If there was no green highlight for optimal water temperatures, I would have to give it 4 stars because there would be no clear telling of what the temperature is. Overall, I would recommend this product. It is sturdy, and easy enough to read as long as your water temperature is in the green zone. I will update this post over time if the suction cup begins to fail.

Hydor Submersible Glass Aquarium Heater - Original Theo

Featured:

• High resistance - the first shatter proof heater 
• Shock resistant Position vertical, horizontal and completely submerged 
• Graduated scale for precise maintenance of set temperature 
• No damage in case of running dry

Description:
Hydor Theo Aquarium Heater (25 watts) Theo Heater. New aquarium heater functioning with the exclusive PTC technology means that this heater will not break or damage when run out of the tank. Theo aquarium heater has all the necessary feature for safe and precise temperature maintenance of the water in your tank. The exclusive technology and the high quality of components guarantee a long lasting product. High resistance - the first shatter proof heater Shock resistant Position vertical, horizontal and completely submerged Graduated scale for precise maintenance of set temperature No damage in case of running dry
Price: $14.39

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 Reviews: 

I spent a lot of time and energy trying to figure out what heater to buy for my Fluval Spec V five-gallon tank. This one was recommended over and over again, but for some reason I tried other ones first. I could have saved myself the trouble - this one lives up to all its positive reviews. It fits in the smaller back compartment perfectly. Many say you can't use the suction cup holder, but I found it to fit just fine with the holder. I prefer to use it to keep it straight and ensure it is not touching the output hose or electrical cord. I positioned the pump so that the side with the grates and flow adjustment faces toward the tank, which puts the tube on a diagonal to reach the hole. The heater fits nicely with it all set up this way, and I don't believe it is touching anything else, which I like for added safety. I cut holes in the output tube as I saw suggested on many forums, to better allow for the water to be heated and recirculated. This works great. This heater keeps the water at a steady temperature consistent with what I have set it to. My thermometer is positioned at the opposite end of the tank, and it holds at a steady 80 degrees, effortlessly. (I have the heater for almost two months now.) My tank houses a betta fish and a snail, btw.