Heaters- Do they need water circulation?

[The Rockster]

Hi,
I use a 30 gallon plastic barrel for my water changes. For my QT/growout tank,(Discus) I like to heat the new water to about 84 degrees(from about 78 degrees).
Sometimes the heater takes a few hours to half a day to heat the 25 gallons to app 84, then my options are to wait or to add the cooler water slowly to the tank to keep the tank temp stable. This is a pain, as I also have a planted tank to do a w/c too.
I want to be able to do both w/cs with heated water in the shortest length of time possible. (hopefully in one afternoon)
So I bought a new 250 watt Stealth Heater, thinking it would heat the 25 gallons up quicker. But I ended up with the same results. Bubbles do form along the heater, showing that the heater is functioning Since I also have changed extension cords with no better results, the only reason I can think of why this is taking so long is that there is no water circulation in the barrel.
Lately I have been stirring the water with the heater, trying to make the heater work faster, with no noticeable results.
Any input would be appreciated..............

 

[John Barkan]

Hello,
For water changes I adjust the hot and cold until it reaches my desired temperature and then run it straight to my tank with a python. I always add a chlorine remover to the tank before doing this, but I assume you do not want to use your hot water line? You could pick up a cheap powerhead for circulation, or use a heater without a temperature controlled shutoff.
Good luck!

 

[The Rockster]

Defies Logic!

Hello,
For water changes I adjust the hot and cold until it reaches my desired temperature and then run it straight to my tank with a python. I always add a chlorine remover to the tank before doing this, but I assume you do not want to use your hot water line? You could pick up a cheap powerhead for circulation, or use a heater without a temperature controlled shutoff.
Good luck!

Thanks for the input.

I don't use a python for 2 reasons:

1.We never found the adapters for Kohl's hand held faucets. Live in a high rise and only have 2 faucets available.

2. I don't like the idea of putting untreated tap water into my planted tank, and then dechlorinating. I want to minimize the stress to my plants and fish. (esp my Discus-whom are like family) I know that lots of folks use the python system, and that is great for them.
If I hadn't read threads on other forums-AC;Krib, etc., about the possible fatal effects of treating the water in the fish tank, I might be tempted to try it. (but not with my fish!!)

I have been keeping fish for years, and this system had worked well for me.I upgraded to a barrel when I bought the bigger, planted tank My fish are 5 years old, huge, and seemly healthy. (The live food; QT tank and UV Sterilizer help.)

I will purchase a powerhead or another new heater, if that is what it takes. However, prior to that, I would like to understand why the new Marineland Stealth Heater- 250 watts will not heat 25 gallons of water, 6 degrees. I have even tried plugging in the heater all night with no results. Once or twice it heated the water in 20 minutes. the heater does work, I can tell by the bubbles that are on the shaft of the heater...............

thanks again for your response.

 

[John Barkan]

I will purchase a powerhead or another new heater, if that is what it takes. However, prior to that, I would like to understand why the new Marineland Stealth Heater- 250 watts will not heat 25 gallons of water, 6 degrees. I have even tried plugging in the heater all night with no results. Once or twice it heated the water in 20 minutes. the heater does work, I can tell by the bubbles that are on the shaft of the heater...............

I have the exact same heater for my 46g tank, and it can raise the temp 6 degrees in 20-30 minutes, but there is plenty of circulation in my tank. You either have a defective unit, or a circulation problem.

 

[The Rockster]

I have the exact same heater for my 46g tank, and it can raise the temp 6 degrees in 20-30 minutes, but there is plenty of circulation in my tank. You either have a defective unit, or a circulation problem.

That is what I am thinking too. The 100 watt Stealth in the QT tank, heats up the water, faster. So I have emailed Marineland with the problem. Also have found a new 100 watt (for up to 30 gals) Stealth in the box (one of my backups), and will try that. This heater was a replacement heater to an 8 year old defect one. Although the guarantee for life is great, ( I have read in Europe a warrantee of 3 years is the max for a heater.) I get tired of playing mail tag!

Is there a way of testing a heater? What if the thermostat in the heater is intermittent? Are the thermostats in the higher wattage heaters less sensitive to water temp fluctuations requiring more circulation? Maybe the 250 watt heater is too large for a 30 gal bucket?
My objective, as previously stated, is to heat 36 gals. of water in about 4 hours.

 

[John Barkan]

You could try it in one of your tanks to see if it can hold a steady temp. Mine maintains the temperature within 1/2 of a degree even though my home varies between 60 at night to 70 during the day. Since you're goal is not to hold a consistent temperature, I would try to return it to the store and get a heater without that feature.

 

[The Rockster]

You could try it in one of your tanks to see if it can hold a steady temp. Mine maintains the temperature within 1/2 of a degree even though my home varies between 60 at night to 70 during the day. Since you're goal is not to hold a consistent temperature, I would try to return it to the store and get a heater without that feature.

Not sure what my next move is. Am not in any hurry---it's in the 80s, here. I got this heater online for rewards points. It cost about $19.00. Buying retail, locally, is a waste of my money.We will probably keep it for backup on the 72 gal. planted tank. That was the plan anyway (Plan B).
Redundancy is good for heaters and air conditioners.........lol

 

[The Rockster]

Future Purchases

Hi,

I am thinking of buying a Koralia # 2 power head, for (Plan A) the heating of the w/c, (25 gals) in my 30 gal barrel (problem explained in prior postings.^)

However, if that does not solve the heating of the water barrel issue, then I could use the power head, in my 72 gallon, medium planted Discus tank. (Plan B) Although I seem to have sufficient water flow from my 2 Eheims spray bars.

Is there a way to adjust the output of the power head ?
Would a #2, supply the approximate correct flow for my planted tank?

 

[VaughnH]

In stagnant water a heater will quickly heat the surrounding water, which then rises by convection current, exposing the heater to cooler water to heat. If you increase the power supplied to the heater it will heat that surrounding water faster, but the thermostat will shut off the power until the convection current cools the heater down again. I am pretty sure the end result will be that the higher wattage heater wouldn't decrease the time to heat the whole stagnant barrel of water by more than a small percentage. Years ago I did some testing of this concept, in reverse. I was trying to water cool a big sheet of nichrome metal used as a high power resistor, by just keeping it in a stagnant container of water. The result was the "heater" generated a massive amount of bubbles, which removed the cooling water from contact with the "heater", which let it overheat, and it quickly erupted like a steam volcano and burned up! To get the heat transfer rate needed to transfer heat quickly to water you absolutely have to have lots of water flow by the heater.

 

[The Rockster]

In stagnant water a heater will quickly heat the surrounding water, which then rises by convection current, exposing the heater to cooler water to heat. If you increase the power supplied to the heater it will heat that surrounding water faster, but the thermostat will shut off the power until the convection current cools the heater down again. I am pretty sure the end result will be that the higher wattage heater wouldn't decrease the time to heat the whole stagnant barrel of water by more than a small percentage. Years ago I did some testing of this concept, in reverse. I was trying to water cool a big sheet of nichrome metal used as a high power resistor, by just keeping it in a stagnant container of water. The result was the "heater" generated a massive amount of bubbles, which removed the cooling water from contact with the "heater", which let it overheat, and it quickly erupted like a steam volcano and burned up! To get the heat transfer rate needed to transfer heat quickly to water you absolutely have to have lots of water flow by the heater.

Makes sense to me..................
Must be a different type of heater in my home water heater. Can't imagine there is any circulation in that tank.

So a power head, would make the heater warm all of the water, and the larger heater would do it faster?

 

[shoggoth43]

Yay thread necromancy.....

Out of curiosity what size opening is on the container? Just like boiling water. Cover the pot if you want it to boil faster. Depending on the surroundings of the container, you could try putting it on a sheet of styrofoam or wrapping the bucket in a blanket or something.

-
S

 

[jonny_ftm]

I don't agree to this,

I also use a 30 gal barrel filled with 25 gal water for my WC. I always used a 300W heater and had to add a second 300W heater to shorten my waiting time. In less than 1h I'm done now compared to desparate long waiting times with one heater (that was already a 300W)

The heaters are longer as they get more power. So water surface contact is much bigger with stronger heaters. Also, I never saw my heaters playing the on/off yoyo. Once they shut off, my water is at the temperature I need. The convection flow is a continuous phenomenon and will ensure a permanent good passive flow around the heaters. The more power is the heater, the more strong will be the convection flow.

For me, your case is normal. You can't expect much more from a 250W heater in your 30 gal barrel. Also, keep in mind that a 300W heater won't consume more power than the 250W one: the thermistance will stop both at desired temperature.

Also, keep your barrel at an ambiant room temperature. I take care to close the window of the room where it is stocked at least 24h before the WC. If the water is too cold, it'll take a much longer time.