Precision Submersible Heaters

Precision Submersible Heaters
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Product No. ML90648-00
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  • Adjustable temperature dial clicks through each degree for accuracy
  • Thermal switch automatically turns off past max preset and resets once the temperature lowers
  • Advanced mica core heating element for efficient heat transfer and enhanced durability
  • Three window positions to view the temperature display

Hope this isn't a stupid question, got a 38gal tank with an OEM heater, do I fully submerge it under water? 

Asked by: FigNewton
Actually, it's a common question for all heaters. And yes, it is fully submersible. You never want more than the top inch or so out of the water. BREX
Answered by: BREX
Date published: 2016-04-14

My 200w heater (ml90443) stop working after about a month. Light stays on,but not heat up. What's the problem?

Asked by: Fish guy
Make sure you are checking a thermometer to determine the temperature of the water. Most people seem to go by the way it "feels". At 78 degrees, it will feel cold to you. If the water temperature is the same as the room temperature, then you are correct, the heater is not working. In this case, call our Consumer Relations Team directly for assistance. 1-800-322-1266. BREX
Answered by: BREX
Date published: 2016-03-04

My Heater is flickering on and off rapidly. Is this normal? 

Asked by: jayh619
The light may flicker, yes. This does not mean the heater is not heating properly. As long as the light goes on/off periodically and the temperature is correct as per whatever thermometer you are using, the heater is functioning correctly. However, if it is having additional issues, I would recommend contacting our Consumer Relations Team at 1-800-322-1266 for further assistance. BREX
Answered by: BREX
Date published: 2016-03-02

what is the temp setting for a beta

Asked by: Terry86
80-84 degrees Fahrenheit. BREX
Answered by: BREX
Date published: 2016-02-29

my tank is only 5 gallons, is that heater ok for a beta

Asked by: Terry86
You would need to purchase the smallest one, which is 50 watts. BREX
Answered by: BREX
Date published: 2016-02-29

What is the temp. Range of your heaters

Asked by: Mike R
65-89 degrees Fahrenheit. BREX
Answered by: BREX
Date published: 2016-02-29

The heater that I got had 2 plastic holders to hold the heater. One of the holders melted and the other broke. Is there anywhere that I can get replacement holders? The heater is about a month old and works great so I don't want to buy another one yet.

Asked by: Morgan1205
Good morning! We would be more than happy to help you and will be emailing you directly for more information. MINI
Answered by: MINI
Date published: 2016-02-23

Small bubbles forming on 200 watt Visi-Therm Submersible Heater

Just started using a new in the box 200 watt Visi-Therm Submersible Heater and it works great in my 55 gallon fresh water aquarium set at 78 degrees! Small bubbles gather all over the heater in random fashion around the unit from the indicator light down to the bottom of the heater. I wipe them off and they come back the next day. I'm using the unit vertically with the enclosed mounting bracket. I am not using a bubblier or any such device and the heater is not coming into contact with anything within the aquarium. After two weeks of wiping bubbles off the unit every day, I gave up and just let the bubbles form as they may. (Item number ML90443-00) (Bar Code number 047431904439). One more: Can I adjust, (slide from top to bottom), the enclosed suction cup bracket anywhere along the unit? Thank you very much!
Asked by: PETM
That is normal, all heaters tend to form little gas bubbles like that. The suction cup bracket should be within the top half of the heater, not the lower portion. BREX
Answered by: BREX
Date published: 2016-02-16

how long is the 50 watt heater?

What is the length of the 50 watt heater?
Asked by: Siamese
Typically the lenght of a 50W heater is going to be approximately 6" long. Thank you, MINI
Answered by: MINI
Date published: 2016-03-20

thermal switch safety feature on the precision submersible heater

I was looking through the Q&A on this product, and was a little confused. One answer stated that if you forget to unplug the heater during a water change and the heater is not fully submersed, it will shut off and once it is submersed again, it will work again. Another answer stated that once it is exposed to air while plugged in, it will not work again. Can you please clarify how the safety-shut off feature works? Under what conditions does it shut off (if it overheats, if it runs dry, if it gets below some minimum water level, or all of the above?) Under what conditions will it function again once this thermal switch has been triggered? Also, how long is the 50 watt heater? I have a 10g marineland aquarium (part of the LED kit), and would prefer to keep the heater vertical. Lastly, while I understand it is fully submersible, does it have to be fully submersed, or is there a minimum water line indicator on this model? Thanks so much!
Asked by: Sadfish
We have two different lines of heaters on the market. One is the Visi Therm and one is the Precision. The Visi Therm is the one that once it shuts off, will not come back on. The Precision has a new shut off that WILL come back on, once the heater has been re-submerged, and had time to cool down, and regulate itself. Both shut off any time the water level drops below the minimum water level line on the heater. The 50 watt heater will fit a 10 gallon tank just fine. It is 7-8 inches long. Even though there is a minimum water line, we highly recommend that any of our heaters be fully submerged at all times. BREX
Answered by: BREX
Date published: 2016-02-04

what is meant by Precision Submersible heater?

i just bought a 200 watt Marineland precision submersible heater for my 50 gallon reef aquarium to replace a 20 watt completely submerged, horizontally mounted heater in the sump. I am unclear about whether completely submersing the heater mounted in the sump is desirable
Asked by: ronntazu
It can definitely be fully submerged, either horizonally or vertically. However, not in a sump, no. We do not recommend placing heaters in sumps for safety reasons. They tend to malfunction in that situation due to the fluctuating water levels. BREX
Answered by: BREX
Date published: 2016-02-03

Thermal fuse on the new Precision heaters.

The manual states that this new heater has a "resettable" thermal fuse to prevent overheating. And that once it is triggered should wait awhile for it to come back in operation. Does that mean this will protect the heater during those times we forget to unplug the heater during water changes? Is the glass resistant to temperature shock?
Asked by: Onjie
Yes, if you forget to unplug the heater and it becomes exposed during a water change, the fuse will shut it off. Once water covers it again, and the heater has had enough time to adjust, it will come back on. The glass is no more resistant to temperature shocks than any other normal glass. BREX
Answered by: BREX
Date published: 2016-01-25

I have bought multiple viso therm heaters along the years and I bought them because of the lifetime warranty but the stores would never take them back

So I don't know how to get them replaced or fixed?
Asked by: Kenshobby
Yes, that heater does indeed have a limited lifetime warranty on it. This means that for the life of that heater, if it fails, you simply send it back to us and we replace it for you. The stores do not honor the warranty, the manufacturer does. Once the heater has been replaced, your warranty is fulfilled and completed. Please call or email us directly for the address to ship the heaters to for your replacements. 1-800-322-1266 BREX
Answered by: BREX
Date published: 2016-01-20

Suction clips to secure heater

I have a heater that the suction cup clips have broken. Can I get the clips to secure it to the side of the aquarium?
Asked by: path9845
Yes, please call or email us directly. BREX
Answered by: BREX
Date published: 2016-01-14

I have a 10 gallon tank for my Betta fish. Do I need the Precision Submersible Heater

Product No ML90648-00
Asked by: Ilipsc12
Yes, you do need a heater. I would recommend the 50 watt Precision heater to keep him at 80-84 degrees Fahrenheit. BREX
Answered by: BREX
Date published: 2016-01-08

Why is my Precision 300 Watt Heater not working?

My Precision 300 watt heater is only a few months old and has only been plugged in when its been submerged, but it isn't working. It doesn't get warm (not even a bit) nor does the light come on (ever). It worked perfectly for the first little bit, but then stopped. It's not an electrical issue because everything else works from the same outlet the heater is plugged into. Help! Why is my heater not workingt?
Asked by: jmfonzy
If the heater ever became exposed to air, for example, during a water change, there is a safety feature that would shut it off. Once this valve turns over, the heater is done. This may have happened at some point, unknowingly. Additionally, a lot of people think the heater is not working but it is really the thermometer, so if the thermometer is reading a temperature LESS than your room or house temperature, this is NOT a heater issue. In the meantime, if the heater definitely is not working, please send it back to us for a replacement. BREX
Answered by: BREX
Date published: 2016-01-05

i have a vth 300 heater can i put this on the bottom of the tank laying horizontaly?on gravel or must it be vertical?

Asked by: Gilly
It can be horizontal but cannot be laying on the gravel or the glass, pressing against anything, etc. BREX
Answered by: BREX
Date published: 2016-01-24

Best position for the heater

I have 2 questions. Reading the posts, you've mentioned that it is best to place the heater near the bubbler or filter so as to be near a source of circulating water. I've got a 29 gallon aquarium, 150 watt Marineland precision heater, no bubbler and a whisper 30 power filter. 1-Do you recommend me placing the heater below the filter, or to the left or right from the filter? (Does it matter?) Also, I've read varying suggestions as to place the heater horizontal, vertical, or at a diagonal. 2-Is one of these positions better than another? Thanks, Bobby
Asked by: BobbyK
Hello. I also a have 150 watt heater on my 29 gallon tank. I am running a Penguin 200. I keep my heater vertically to the left of my filter (opposite side of the intake). My heater is almost roughing the left wall and is right next to the filter. Position or orientation does not really matter but placing it near the filter improves the circulation of water water throughout the tank.
Answered by: JojoP1777
Date published: 2016-01-04

heater full of water

Hello I recently had to replace two heaters one does not turn on, the other one filled up with water .How do you go about a warranty claim?
Asked by: brentvan
I recently had to return a faulty heater due to water intrusion. You can call the company's headquarters under the "Contact us" page or you could send an email, which is found under the same page. Calling will be faster and more direct but email will only take a day or two at most. These heaters have a lifetime warranty so when you send your initial email or phone call, you need to have the code at the back of the rubber cap of the heater (where the dial is). This code is needed to send you a new heater. Hope this helps.
Answered by: JojoP1777
Date published: 2016-01-04


will this melt my plastic 3 gallon tank? and i also need a light that fits my little tank. thanks
Asked by: alpha
I don't think you tank is actually plastic but rather acrylic. Regardless, the heater will not melt your tank. If you need a light, please look under the lighting section.
Answered by: JojoP1777
Date published: 2016-01-05

Product No. ML90648-00

Hello, I just purchased these heater at the beginning of October, and I noticed yesterday (11/30/15), when I stuck my hand in the water it felt cold, the temp in the tank had dropped to 72 degrees. I unplugged the heater and plugged it back in but could not get it to work. I took it from the tank and put it in a pitcher of water and got it to come back on, but it seams that every time I put the temperature knob under water it would shut off again. The directions said fully submersible and the heater only had a minimum water level mark on it so I am not sure what the problem is. I had the temperature set at 79 (it was the one down from 82). I would like to know if this is a faulty heater. It has been working for the last 10 hours, but I can't shut my aquarium lid because it only works with the knob above the water.
Asked by: JHHHHHHH
I have never heard of a heater functioning only with the knob out of the water. They usually either heat....or don't heat.....if there is an issue. The water level has to be above the minimum water line but the heater does not have to be fully submerged. I would add a second thermometer to verify the temperature, and leave the heater installed the way you prefer to have it installed, and observe the temperature for several hours (at least 12 hours). If both thermometers indicate the temperature is cold, then yes, the heater is not functioning properly and you would qualify for warranty assistance. Make sure nothing is pressing against the heater, such as plants, rocks, wood, etc. BREX
Answered by: BREX
Date published: 2015-12-02

Please inform where the aquarium heater is made?

Please inform where the aquarium heater is made, still made in Italy or it is made in China now?
Asked by: AleW
China. BREX
Answered by: BREX
Date published: 2015-11-30

What is the setable temp range.

What is the high and low setting for the adjustable thermostat? I could not find it listed.
Asked by: Junoflydog
65-89 degrees Fahrenheit BREX
Answered by: BREX
Date published: 2015-11-19

Internal thermostat

Does this heater have an internal thermostat and if so does this mean I can place it below the water line horizontally near the bottom for a fry tank
Asked by: Carl393
Yes it does, and yes, it is fully submersible. It can be vertical or horizontal, it just needs to be in a filled aquarium and not buried or with anything pressing against it. BREX
Answered by: BREX
Date published: 2015-09-11

Could the heater control the temperature into 55c ?

Asked by: Joanna
The Precision Submersible heaters have a maximum temperature setting of 89 Fahrenheit, which would be 31 Celcius. If you were to raise the temperature to the 55 Celcius then the temperature in the tank would be approximately 131 degrees Fahrenheit. The standard recommendation for tropical fish is 78 degrees Fahrenheit. MINI
Answered by: MINI
Date published: 2015-09-04

Indicator light on the precision submersible heater

Help me find the location on tube
Asked by: Omagoff
The indicator light on the Precision Submersible Heaters should be in the middle of the circle at the bottom of the red temperature gauge that is along the length of the heater. MINI
Answered by: MINI
Date published: 2015-08-31

Does a pre-set heater mean that the temperature is already set?

I have a pre-set heater? Does this mean that the temperature is already set? The test strip shows 80 degrees but the water feels cooler than that. How can I be sure that the temperature is correct. I couldn't find a dial to set it. Also, There was a red light on when I first plugged it in. Now the light is not on. Does this mean the temperature has reached the correct setting?
Asked by: 5kitties
A pre-set heater is set to keep the water between 76 and 80 degrees. Keeping an eye on the thermometer is how you know if the heater is working correctly or not. At this time of year, it will rarely turn on. This is why you aren't seeing the light at this time, because the heater does not need to be on. One thing that helps is to know what the room temperature is in that room and compare it to the tank temperature. If the tank temperature is lower than the room temperature, that is a broken thermometer. If they are exactly the same, then either the room is just very warm or the heater is not working. BREX
Answered by: BREX
Date published: 2015-07-20

Heater Confusion

I purchased the Marineland 29gal Starter Kit back in January, and everything has been working great so far. The tank was initially upstairs, and I would see the heater light blink on periodically through the day. Recently, we had to move the tank downstairs. The AC unit is currently broken downstairs which keeps the temperature inside around 80 in the summer. My heater has and is set for 80, and the light hasn't blinked on since we moved the tank downstairs. Is that because it doesn't need to come on until the AC cools the house off again? Or do I need to replace my heater?
Asked by: Hannah938
It is because it is not needed at this time. If the house is at 80, the water temperature will not drop below that temperature, so the heater is not going to come on. BREX
Answered by: BREX
Date published: 2015-06-22


Should i avoid putting this heater above or around my bubble wall? Does it make any difference, does it help or hinder? Where is the best place for this heater?
Asked by: knastabooh
The best place to put a heater is near the most water movement. This helps to circulate the heat around the tank, so we usually recommend near a filter or a bubbler. BREX
Answered by: BREX
Date published: 2015-06-04

fully submersible

Are your heaters fully sunbersable or does the top needed to be above the water.
Asked by: swatcapt
They are fully submersible. BREX
Answered by: BREX
Date published: 2015-07-17
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