Precision Submersible Heaters

Precision Submersible Heaters
  • Image 1
  • Image 2
  • Image 3
  • Image 4
  • Image 5
  • Image 6
  • Image 7
  • Image 8
  • Image 9
Product No. ML90648-00
Find a Store In Stock
  • 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 3.6 out of 5 by 18.
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
  • y_2018, m_1, d_22, h_10
  • bvseo_bulk, prod_bvrr, vn_bulk_2.0.6
  • cp_2, bvpage2n
  • co_hasreviews, tv_0, tr_18
  • loc_en_US, sid_ML90648, prod, sort_[SortEntry(order=SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_marineland

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

How much is precision 400 tank heater??

Asked by: Wheels
Thank you for your interest in this Marineland heater! We do not sell directly, unfortunately. This is available through most local pet and fish stores, as well as many online vendors. Average price will be around $35. BREX
Answered by: BREX
Date published: 2016-12-30

My 90648 -00 heater, was replaced in six months with a 90439 and replaced with another 90439 on Jan 30 2016. Third heater in less than 2 years.Heating a ten gallon tank to max 75,room temp 70 Am I under power? Have not had this many issues in 40 years

Asked by: mad fish
Thank you for your support of Marineland products! No, you are not undersized. Customer feedback has indicated that heaters may fail due to: - their being exposed to air during a water change or because of water evaporation - build up of hard water deposits, algae, etc., over time - burying them in gravel or having ornaments, etc., pressing against them Please contact us directly if you require further assistance at 1-800-322-1266. BREX
Answered by: BREX
Date published: 2016-12-30

temp range on this heater is??? from what to what? I know it can heat to 80 at least but I need to only heat up to 68degrees. can this be set that low?

Asked by: cold weather
Thank you for your interest in this Marineland product! The range is 65-88 degrees Fahrenheit. BREX
Answered by: BREX
Date published: 2016-12-19

Are they fully submersible?

Asked by: ReefinLuis
Thank you for your interest in this Marineland product! Yes, they are fully submersible. In fact, you can position them either horizontal or vertical in the tank. Just make sure they are not buried in the gravel and do not have anything pressing up against them. BREX
Answered by: BREX
Date published: 2016-12-15

what size heater do I need for a 40 gallon tank?

Asked by: Brett6500
Thank you for contacting us! Typically, we recommend around 5 watts per gallon of water, so for your tank, around a 200 watt heater should suffice. BREX
Answered by: BREX
Date published: 2016-12-12

What is the exact length of the 50 watt heater (including the dial on top)?

Asked by: scottb
7". BREX
Answered by: BREX
Date published: 2017-01-08

I have had this 50W heater for a little over a week. It worked great to keep my 5 gallon tank at 79 degrees. Now however it is on all of the time and the tank sits barley above 75. What when wrong?

Asked by: Novorapid
Thank you for contacting us! If the water level dropped and exposed the heater, this may have caused an issue. Make sure the tank is covered appropriately, at all times, as well. And last, check the temperature with a second thermometer as the first one may not be working properly. Assuming that it is working correctly, did the house get cooler due to a cold front, weather wise? If you are unable to resolve this issue, please call us at 1-800-322-1266 so we may assist you. BREX
Answered by: BREX
Date published: 2016-11-28

What size heater (wattage) do I need for a 20 gallon freshwater aquarium?

Asked by: John Junior
Thanks for your question! Typically, you want 3-5 watts per gallon of water, depending on your home's room temperature. The cooler the house, the more wattage you need. So on average, you want a 100 watt heater for a 20 gallon tank. BREX
Answered by: BREX
Date published: 2016-11-28

Can i use the 50 watt in a 2.5 gal betta tank?

Asked by: Hann
That could be a bit much for that small of a tank. If the room he is in is pretty chilly, it should be okay since it is an adjustable heater. BREX
Answered by: BREX
Date published: 2016-10-11

Which way do I turn the dial to lower the temp setting?

Asked by: Dwingo
You would turn it towards the lower temperature settings. There are numbers around the dial if you are viewing from the top, and a vertical array of settings on the front of the heater as well so you can view it from the front too. If you cannot see either for some reason, turn the dial counter clockwise. BREX
Answered by: BREX
Date published: 2016-12-31

What size heater do I need for your 20 gallon tank? My present Marineland heater is still working but the black rubber is falling apart. I purchased the whole kit at Petsmart about five years ago.

Asked by: Cheri
You typically want about 5 watts per gallon so around 100 watts would be perfect for your tank. BREX
Answered by: BREX
Date published: 2017-01-08

Will this heater cool the water also? I am looking for a submersible type cooler with a temperature dial that I can set the temperature at about 65 degrees and let it keep the water cool for my hydroponics system.

Asked by: Burger Bob
No, it is only a heater. You are looking for a chiller. This is a very expensive piece of equipment most often used by marine hobbyists. It runs approximately $800+. Try websites such as BREX
Answered by: BREX
Date published: 2016-09-27

I have the 50watt heater in my 5 gal take for my betta and it has begun flickering instead of being solid. Do I need to replace it?

Asked by: BettaGirl47
No, this is just a light issue, and does not necessarily reflect how it is heating. Check your thermometer regularly and make sure the temperature is maintaining correctly. If it is, you are fine, if it fluctuates more than a degree or two, irregularly, then I would replace it. BREX
Answered by: BREX
Date published: 2016-09-09

I have a 50 watt ro2983 out of a topfin 10 gallon set up. it does not state if it is fully submersible at all in the instructions.  I assumed it was so I submerged it.  No light ever came on.  I kept the dial at the line it was set on. what's wrong?

Asked by: Amamda
It is indeed fully submersible. At this time of year, however, the water may be warm enough to not need a heater. Be sure to have a quality thermometer on tank and check the temperature at least once daily. Also, make sure you do not have the heater installed with the light on the backside. BREX
Answered by: BREX
Date published: 2017-01-08
  • y_2018, m_1, d_22, h_10CST
  • bvseo_bulk, prod_bvqa, vn_bulk_2.0.6
  • cp_2, bvpage2n
  • co_hasquestionsanswers, tq_94
  • loc_en_US, sid_ML90648, prod, sort_[SortEntry(order=LAST_APPROVED_ANSWER_SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_marineland
ML90648 50-watt
ML90649 75-watt 
ML90650 100-watt 
ML90651 150-watt 
ML90652 200-watt 
ML90653 250-watt 
ML90654 300-watt 
ML90655 400-watt