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
Precision Submersible Heaters is rated 3.1 out of 5 by 25.
Rated 2 out of 5 by from Trouble w/ 400 Watt Heaters I've purchased two and both have condensation INSIDE the unit within a week. This is extremely worrisome to me.
Date published: 2018-01-01
Rated 1 out of 5 by from 1 month? I purchased the 400w and it only lasted 1 month. Pretty frustrating when you have a reef tank and have your temps drop overnight.
Date published: 2017-11-23
Rated 5 out of 5 by from Guarantee Great company. It did poop out at plug after about a year, but they replaced it, no questions other than "what is your address?"! Valerie
Date published: 2017-10-06
Rated 1 out of 5 by from Junk I have had aquariums for 40 years. It seems all products have been cheaping out over the last five years and charging ridiculous prices for this non funtional product. These are no exception. I have had it for less than a year. Clearly the seals are no good. The temp hasn't been steady and it started whistling about a month ago. I bought a different brand heater and we will see how that goes. What good is a lifetime warranty if you have to just get another piece of junk from Marineland. I am going to attempt returning to the place of purchase for a refund.
Date published: 2017-08-07
Rated 2 out of 5 by from Heater failure. I've had this heater for a little over ~7 months now and it worked great. Until recently I noticed my fish getting lethargic. I felt the water and it was extremely cold. The heater has not warmed up even after unplugging, turning up the heat and down and I believe it has failed. It hasn't even been a year with it.
Date published: 2017-05-27
Rated 4 out of 5 by from Quality Product and Fantastic Customer Service The title says it all I have Marineland heaters in all my tanks and I typically get about 2-3 years out of each heater but they keep my tank at a very steady temp and when they die they are replaced in a timely manor. I couldn't ask for much more out of a product and company. Photo is for Marineland, you guys kept your end of the warranty up and I kept my word about terminating the old heater.
Date published: 2017-02-20
Rated 5 out of 5 by from Great Features I purchased this heater to replace and older one. I am so pleased with the features as well as the performance. I also like how it blends in with the tank. It's so easy to set and read. I'm impressed!!! As always Marineland has produced a great product!
Date published: 2017-01-12
Rated 1 out of 5 by from Filled with condensation Had it for a week and a half and it filled with condensation and quit working. My tank, canister filter and power head are all Marineland and have been very happy, but this Marineland product let me down.
Date published: 2016-10-29
Rated 1 out of 5 by from Condensation Problem I bought this 5 months ago and it worked okay, but it ran very hot. Then I noticed an extreme amount of condensation inside. I returned it because condensation shouldn't happen that soon. It's been less than a day and it's already beginning to have condensation. I am very unhappy with this product.
Date published: 2016-05-21
Rated 5 out of 5 by from Great product!!! I bought this heater a few months ago. It works great. I purchased it as a result of a lesser brand shorting out.
Date published: 2016-03-18
Rated 5 out of 5 by from Great heater I have used many different brands of heaters in my 22 years of fish keeping and this product is the best. Very accurate and affordable.
Date published: 2016-02-14
Rated 5 out of 5 by from Great company that stands behind there product. I have been in the hobby for 20 years and I have always bought these heaters and they have worked for years.
Date published: 2016-01-20
Rated 5 out of 5 by from Very accurate holds perfect temp Awesome heater just set it and forget it. There was no need to baby sit this heater for hours or days like other brands. With other brands I had to buy an expensive calibrated thermometer to calibrate my heater but not with this one I set it and it was spot on. Great product.
Date published: 2016-01-19
Rated 5 out of 5 by from Best Got Better! I've had many Marineland heaters for various tanks. They have yet to fail me. This new Precision model is awesome! It feels more accurate than the previous model, which I still use. I have the new model in 400 watts for my 100 gallon aquarium. It's works so great and has great features. To me, the previous model was the best but the new model made the best better. I have mind fully submerged and in a horizontal position. My peacock bass, bluegill, and largemouth bass are doing well at 70-72 degrees. The temperature stays accurate 24/7.
Date published: 2016-01-02
Rated 4 out of 5 by from Great heater but has a significant design flaw The Good:- Temperature Dial: it shows you exactly the temperature it will heat the water. It also clicks to help you adjust the temperature to exactly where your fish will be comfortable.- Built-in visible thermometer and light that shows you when it is actively heating.- 3-way viewing mounting bracket: this is great if you want to mount your heater to the side of the tank and still want to see the light and thermometer.- Overall design is very sleek with clean lines; this heater is not an eyesore.The Bad:- Problems with water intrusion. I purchased this heater for my 29g community tank in August. In October/November I noticed rust and water condensation on the heating element inside the glass. It stopped working in December. Customer Service was great and sent me a new one free of charge. I think the sealing needs to be improved in order to help it last longer. Don't blame the heater for failing, it could just be the sealant.
Date published: 2015-12-31
Rated 5 out of 5 by from Works great Works great. Click temp set feature a plus. I've had other brands, this is the best.
Date published: 2015-03-05
Rated 5 out of 5 by from This product is great I just got this heater and it works great. My 10 gallon aquarium was at 68 which is way to cold. So I got the visi therm and now the tank is at 80.this product is great.
Date published: 2015-02-05
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I have the heater from the Marineland front curve 38 gallon it doesn't show different degrees how do I know I am heating the water to 78 or 79 degrees?

Asked by: Big Papa
There are three marks - a + sigh, a minus sigh, and an arrow or triangular mark. This latter mark is the spot that represents 78 degrees. Set the heater here initially, and leave it for a few hours. If the temperature in the tank does not reach this mark or goes past it, adjust the heater in one direction or the other. Move the knob, one click at a time, waiting a second or two in between each adjustment. BREX
Answered by: BREX
Date published: 2018-04-24

I need to run 2 smaller physical size heaters in an 80 gallon. Can you recommend a wattage for each? Thank you

Asked by: Lefty
You need to have at least 2, 200 watt heaters. BREX
Answered by: BREX
Date published: 2018-02-23

I have a 10g aquarium kit w.o temp manuals. The heater it came with doesn't have the temperatures on the dial. Are the temp positions the same as the one with the numbers listed and does it auto turn on and off? Also, please explain the thermometer strip

Asked by: Jenn111
You should have a + sign, a - sign and a arrow or triangular mark. The latter represents 78 degrees. Start with it set there, give it several hours to bring the temperature up in the tank then move it one click in the direction you need to adjust the temperature - + to increase the temperature, - to decrease the temperature. Nothing to explain. Peel the back off and stick it to the outside of the tank in a location that is visible to you, but does not disrupt the view of the tank. BREX
Answered by: BREX
Date published: 2018-02-21

Can I purchase the clip and suction cups for this heater? I would like to purchase two if possible. Thank you.

Asked by: KathyDip
Of course, here you go: BREX
Answered by: BREX
Date published: 2018-02-12

The heater can be fully submerged even the temp dial? 

Asked by: Ashley1142
Yes, correct, even the dial can be submerged. BREX
Answered by: BREX
Date published: 2018-02-01

Is the heater completely submersible (including the dial and clicker at top?

Asked by: Lillie
Yes, it is fully submersible Lillie! You can leave the black rubber part up out of the water if it is easier for you, but all of the glass must be submerged, at all times. BREX
Answered by: BREX
Date published: 2018-03-18

Does "fully submersible" include the temp dial? Should the temp dial at the top be under water?

Asked by: Keccbond
Yes, it means that the entire heater is fully submersible, including the dial. The dial does not have to be under water, but the water level line should have water above it. BREX
Answered by: BREX
Date published: 2018-01-16

Is the top supposed to light up when it's "heating"

Asked by: Mbarkerco
No, there should just be a red "dot" near the top of the heater. It is pretty darned bright and you may see some reflection around it, making it appear the top is lit up, but no, it should not be. BREX
Answered by: BREX
Date published: 2018-03-26

How much of the heater needs to be underwater?

Asked by: Blizzardman8
All of it, it is fully submersible. BREX
Answered by: BREX
Date published: 2018-01-15

Is there a recall on ml90638?

Asked by: Cooter
No, we have never had a recall on the VisiTherm or Precision heaters. BREX
Answered by: BREX
Date published: 2018-01-08

I have a 10W Mini Heater for my 5 Gal. Tank. Is there a light that shows it's on ?

Asked by: Mia Mouse
No, that heater does not come with a light. You should be using a thermometer in conjunction with it to ensure the water temperature is proper. BREX
Answered by: BREX
Date published: 2018-01-08

I have a heater in each tank. One is set for 77 and a red light is always on. The other is set for 80 and there is no light on- I believe a red light use to be on all the time. Is it still working?

Asked by: Liss
The light is not supposed to be on all the time, it goes off when the tank is at the proper temperature. To determine if all is correct, you need an aquarium thermometer to read the water temperature. Always have one or two of these installed on a tank and take at least one reading daily. BREX
Answered by: BREX
Date published: 2018-01-05

My ML90648 50w heater has been working flawlessly for overe two years, but I just broke the mounting bracket (piece w/ suctions cups). Is that part available as a replacement? How / where could I get one?

Asked by: DJ Saberniak Jr
Order it from our site. BREX
Answered by: BREX
Date published: 2017-12-20

Are theses heaters fully submersible? 

Asked by: Cyndih
Yes, they sure are! BREX
Answered by: BREX
Date published: 2017-12-04

How long in inches is the 50 watt heater?

Asked by: Zack01
My apologies, total typo! It is 9", including the knob. Cord is still 6 feet though. BREX
Answered by: BREX
Date published: 2017-11-09

Would this product work in an 1800 gallon pond? If not do you have any recommendations?

Asked by: LG3313
No, our heaters are for indoor aquarium use only. We do have another brand, Tetra, with a pond deicer. BREX
Answered by: BREX
Date published: 2017-11-02

How far can the water come up the top of a precision 200 submersible heater?

Asked by: Dr Tom
It should cover it completely. BREX
Answered by: BREX
Date published: 2017-10-30

 300 watt HMB300. The temp is set at 75 degrees. I have two thermometers one at the bottom of the tank and one in the sump pump. Tank temp is 78 and sump temp is 80. My question is does the red light suppose to on, mine never goes out!

Asked by: The Beast
The light should go on and off. When you set the temperature are you looking at the front of the heater or the knob on top? Make sure your knob is lined up with the 75 on the gauge surrounding it, not necessarily with the front of the heater. BREX
Answered by: BREX
Date published: 2017-10-24

My fish (Pacu's) are large and will attack the heater. Will it shatter like my old heater did (not Marineland) ?

Asked by: Al G
Yes, and glass aquarium heater is susceptible to breakage by large, aggressive fish. You may want to place it behind some large decor like driftwood. If you ever buy a larger tank, consider one with overflows and place it in the overflow. BREX
Answered by: BREX
Date published: 2017-10-24

Are the Marineland - Precision Submersible Heaters safe to use with small aquatic turtles (Red Eared Sliders) ?

Asked by: justmonkeybiz
Yes, as long as you place them fully submerged, not touching anything, and behind something so the turtle cannot reach them. You do not want the turtle climbing on them, possibly breaking them or knocking them loose. We do offer a turtle heater under the brand, Tetra. This is suitable for up to around 15 gallons of water in a turtle tank since such tanks are rarely enclosed. If it is enclosed, up to 30 gallons. BREX
Answered by: BREX
Date published: 2017-09-20

I recently purchased an HT10 submersible heater, the light stays green and the water feels cool.....How far down am I  supposed to immerse it?  Up to the top wire?

Asked by: tomr404
It should be fully submerged. At this time of year, heaters rarely turn on since room temps tend to be warmer. Use a thermometer to gauge the temperature since 78 degrees is 20 degrees cooler than your body temp and will feel chilly to you. BREX
Answered by: BREX
Date published: 2017-07-27

Hi, i´ve a 250w model that was turned off in the tank while cycling. After that period, i turned it on and worked fine for a couple of days, but suddenly, it doesnt turn on and water is at room temp.Water level was ALWAYS above minimum,not exposed to air.

Asked by: Marco M
Thanks for answering. Room temp is 25-26ºC, tank is 220 L and yes, its covered. Heater is set to 28ºC (~82F). As mentioned, the couple if days it actually worked, LED was on and off at times, as expected, and temperature of water was correct (28ºC), measured by 2 different termometer kinds at the same time. After that, LED no longer turns on, and temp is same as room temp.
Answered by: Marco M
Date published: 2017-07-19

Have 200w heater.  Minimum (low) water level is clearly marked.  Can't find a maximum (high) water level

Asked by: BillC1122
It is fully submersible, and should be submerged at all times. BREX
Answered by: BREX
Date published: 2017-06-20

I don't think my heater is working the temp in the tank hasn't gone up and I don't feel any heat coming from the heater when I touch it, shouldn't it be warm?

Asked by: clr031007
It will only feel warm when it is actually lit up. However, the water in the tank will disperse the heat, so you may not notice a warmth around it. It can take several hours to change the temperature, depending on the size of the tank, and the room temperature. At this time of year, heaters often are not needed. You might try a second thermometer to make sure the first one is working right. BREX
Answered by: BREX
Date published: 2017-06-01

I purchased precision heater from Drs Foster and Smith on the 30th May 2016 it failed last night with temperature falling to 66.7. The model number is ML 90652-00 (200 watt). Can you advise how I obtain a replacement under the lifetime warranty?

Asked by: Smudge 1960
Hi Kevin, If the heater has failed you would need to contact us regarding warranty via 1-800-322-1266. Once it is replaced, your warranty is fulfilled. 66.7 is a pretty low temperature, and would need to be the room temperature to be accurate. Otherwise, you have a thermometer issue, not a heater one. Warranty requires the lot code off a heater or a receipt for the heater. We look forward to hearing from you! BREX
Answered by: BREX
Date published: 2017-05-02

The light on my 250 watt heater is constantly on but the heater is not working. My tank dropped to 50 degrees. 

Asked by: Frosty2431
The only possible way a tank could be 50 degrees is if it is housed outside, in a garage, etc. By a law of physics, the lowest temperature it will reach is your room temperature. If your house is being kept as cool as 50 degrees, you will need a heater that is one to two times the recommended wattage for that size tank, and preferably two heaters, one for each end. All aquarium heaters are calibrated to the average room temperature of 73.4 degrees (this is a scientific lab calibration), and one heater cannot make up that large of a difference. We recommend checking the water temperature with a second thermometer to make sure the one currently in use is accurate. BREX
Answered by: BREX
Date published: 2017-07-11

Hi my heater temperature shown only 65 even though I turn my heater up to 82 is this normal and may I know how can I send pictures to this column thanks 

Asked by: Fat girl
No, but then you may have a thermometer issue or a heater issue. If your room temperature is 65 degrees, then the heater may not be working. If the room temperature is several degrees higher than 65, your thermometer is not working. Email pics to BREX
Answered by: BREX
Date published: 2017-04-11

Can thid heater be completely submersed in the water...the dial part is what wondering about

Asked by: Bonnie110
Yes, it is fully submersible. BREX
Answered by: BREX
Date published: 2017-04-10

How do I know which way to turn the dial to adjust the temperature?

Asked by: Evidence Ann
Thank you for your interest in this Marineland product! The dial has corresponding numbers for temperature settings. You would turn the tip of the dial to the temperature you wish the heater to be set on. It can be turned in either direction, depending on whether you are lowering or raising the temperature. Make sure you turn only one click at a time, to ensure proper adjustment. BREX
Answered by: BREX
Date published: 2017-01-03

I just purchased a Marineland Visi-Therm aquarium heater.  When installing, is it to be totally, including thr red temp adjusting knob, underwater?

Asked by: Terrty
Thank you for purchasing this Marineland product! Yes, it should be fully submerged at all times, including the red knob. BREX
Answered by: BREX
Date published: 2017-01-03
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ML90648 50-watt
ML90649 75-watt 
ML90650 100-watt 
ML90651 150-watt 
ML90652 200-watt 
ML90653 250-watt 
ML90654 300-watt 
ML90655 400-watt