DIY Chiller

[timebomb]

Hi, guys,

I came home from work today to see 24.1 C. That's pretty good, considering how hot it is today. Room temperature is 31.5 and the temp in my chiller bag is 22.4.

I switched off the powerhead in the chiller bag. Let's see if the temp drops further.

Wright, when I replaced the chiller tank with a plastic bag, I turned the thermostat back to midway. It's been set at that level since.

I was discussing the DIY chiller with some colleagues and they all agreed that if I add salt to the water in the chiller bag, it will bring the temp down further. They can't explain why though but they all say ice creams sellers use salt to prevent ice from melting. I thought it was dry ice. What do you all think?

Loh K L

[TyroneGenade]

Salt will alter the chemical structure of water (i.e. how the little H2O molecules interact). This reduces their energy (because now that are lugging salt around) so the average temperature (which we measure as temperature) is lower. Alcohol does the same thing but it may leach into your fishtank via the plastic hose... although probably not.

The salt you want to add is potassium chloride. The temperature will however requilibriate to whatever temperature that is... which may just be 21 or 22°C again.

Give it a try if it isn't too expensive.

Ciao

[whuntley]

Salt is used in ice-cream makers to get a lower temperature, but the salt does not remove BTUs and create the lower temperature. It lowers the freezing point of the water, and that gets the liquid temperature down to good ice-cream making levels. The liquid is essential for heat transfer from the milk solution to the ice. The colder the liquid, the quicker the ice-cream forms.

Pure water freezes at 0C, and salt water freezes at 0F, or 32 defrees F lower. Solid ice can be at any temperature below the freezing point of the particular solution. Good freezers run at -10F or below or 42 degrees below the freezing point of plain water.

AFAIK, the only effect of adding salt is to alter the freezing point. One has to add or subtract BTUs (Calories, kilocalories?) to actually alter the temperature. The ice can do that to ice cream if it is below the current melting point of the salt solution. Salting your chiller bag won't do a blessed thing, because no freezing or melting is involved.

Salt is used to de-ice roads, not because it warms the road, but because it dissolves in surface moisture and reduces the freezing/melting temperature of the ice, turning it liquid but at still the same temperature. They usually add black oiled gravel to collect some solar help, which does raise the temperature.

Wright

PS. There's no excuse for not lowering the thermostat setting to see where that takes you, KL. If the freezer is power limited and never turns off, it won't do a thing. OTOH, it might be all you need to do.

[TyroneGenade]

Actually, potassium chloride does lower the temperature of water. It is one of the novel properties of this salt. Your fish tank will probably raise the temperature unless you increase the heat sink capacity of the chiller bag...

So back to square one...

tt4n

[whuntley]

Actually, potassium chloride does lower the temperature of water. It is one of the novel properties of this salt.
tt4n

I'm puzzled. Where does the energy to lower the water temperature go? The salt has only a negligible effect on the density (specific gravity) or thermal storage capacity. The ionization of potassium chloride is not an enormously endothermic reaction, so that isn't what lowers the temperature.

Tyrone. You aren't trying another scotch-and-water-diet theory on us, are you?


Wright

[TyroneGenade]

Where do you find those smilies??? Let me guess... "view more emoticons."

This question of the KCl is a big mystery. I don't think anyone knows. Maybe because K is heavier than Na it can reduce the energy of the water... who knows... I do know now that I have time to digest you 2nd last post that I was talking out of my arse... your point about the salt disrupting the structure of water making it more difficult to freeze is more sensible so please don't

tt4n

[whuntley]

Suggestion for a mini-experiment:

Take some "No-Salt" o/e source of KCl, and drop a measured amount in a container with melting ice in water. What happens to the temperature? It drops quickly as the salt is dissolved and stirred, of course.

Now take a container of cool tap water (no ice) and repeat the test.


Wright \/

[Robert]

Hi,
I’m new to this forum and at first I want to say hello to everybody! BTW, I’m a German, so please forgive me some of my misspellings .
Can anybody explain to me why it is so important to get the tank temperature below 24°C? I live in a region where most of the year I have to use heaters to heat my tanks. I heat them up to 24-25°C. Should I throw them away and be happy if the tank temperature reaches the 20-22°C of the room temperature? Is 22°C not a little bit too cold for tropical fishes and plants? I think 24-25°C are perfect and there is no positive effect if the water is cooler than this temperature. Only if your want to breed some dwarf shrimps like Crystal Reds it’s really useful to have cooler water (which is no problem for me but for you). But I guess you don’t want to breed any fishes or shrimps in your 380liters display tank, so why do you want to cool it to less than 24°C?
Loh K L, if you have some problems with the leaking fridge, then try to find the leaks and use some epoxid resin (I hope that this is the right translation for “Epoxid Hartz”). There should be no problem while using it and it is much cheaper if you compare it to the special silicone for aquarium usage. A friend of mine used this resin to get his balcony water proof and it works fine. In my regions we have winters with temperatures up to –20°C but nothing happened to the epoxid resin on his balcony. Paint the walls of the fridge several times to be sure that you cover all leaks. It should work pretty good and if there is still a bigger leak, you can also use silicone for it. I don’t know if it effect the tank water but I guess it won’t hand over anything to the environment. Perhaps some of the experts here can say something about this artificial resin.

BTW, perhaps you can reach the 23°C-mark if you modify the fridge itself. Everybody seems to think only about the heat which comes from the tank but nobody thinks about the heat of the surrounding air. The whole fridge should have a good isolation but you changed the cover and it looks really thin. If you isolate the cover of the fridge in a better way, less warmth from the surrounding air can disturb the cooling-process of the tank water. It should be no problem to isolate the inner part of the cover with some styrofoam.
To isolate the back and the bottom of the tank should also help a bit and nobody cares about these sites. If you have a rectangular tank and the width is only half as long as the length of the tank, then these 2 sites are 40% of the whole surface of the tank. You lose cold at all sites of the tank and if you can isolate 40% of the surface, you should see a big difference because heat can now only affect 60% of the surface and not 100%. This helps your fridge to cool the water and you should get cooler water in your tank (even if there is no need for much cooler water but you can also safe some energy and money if it works).

Best regards

Robert

[whuntley]

Welcome to the forum, Robert.

Many killifish like sub-tropical temperatures. Aphyos from the highlands of Cameroon, Gabon, and Congo (or whatever it is called this week) live in small swift brooks that are not particularly warm.

Keeping them healthy and, particularly, breeding can mean maintaining them at 20-23C. Diapterons and A. jorgenscheeli are classic examples of cooler water killies.

Many plants, like the Madagascar Lace Leaf also do much better in cooler water. The SG guys are avid plant growers, too.

The two-part cement you refer to is, in English, epoxy resin.

The compact freezer uses the outer skin as the way heat is radiated or conducted to the room, so insulating it isn't a very good thing to do. It is already very hot to the touch. All refrigerators, freezers and air conditioners that use fluid pumping are heat pumps, with cold coils inside and hot coils outside. It might help a little bit if the heat could be drawn away from the hot case with fans or finned heat-sink material.

Your spelling is fine, and probably better than mine, if you use the neat spell checker that was just installed.

Wright

[Piscesgirl]

perfect and there is no positive effect if the water is cooler than this temperature. Only if your want to breed some dwarf shrimps like Crystal Reds it’s really useful to have cooler water (which is no problem for me but for you).

Are you saying that Crystal Red Bee shrimp need cooler than 25 C to breed? Mine breed fine at 78 F. (26 C?), and it sometimes get to 80 F.

[FC]

I switched off the powerhead in the chiller bag. Let's see if the temp drops further.

Good move.

Wright, when I replaced the chiller tank with a plastic bag, I turned the thermostat back to midway. It's been set at that level since.

The change to bag idea should work better. Now, you should set to maximum to see how far the fridge (for its' size) can bring down the Aquarium's temperature.

I was discussing the DIY chiller with some colleagues and they all agreed that if I add salt to the water in the chiller bag, it will bring the temp down further.

Addition of salt is useless for your case. Why?
For such application, salt's sole function is to lower the freezing point of water and increase the heat (cold) storing capacity (if THAT water EVER freeze). For certain, your fridge does not have the capacity/power to froze the water in the bag.

If the water do freeze, then the addition of salt would facilitate the "salted" water to lower beyond zero degree celcius. This is then important and effective because it broke the zero degree barrier, thereby increasing its' capacity to cool, for your case, the hosed water.

[timebomb]

Hi,I’m new to this forum and at first I want to say hello to everybody! BTW, I’m a German, so please forgive me some of my misspellings

Hello to you too, Robert. Welcome to the forum.

The weather here in Singapore is hot the whole year round. Mostly, the temperature of our tanks are about 30 to 33°C if there's no cooling equipment. With fans, we can get the temp down to about 26 to 28°C. That's low enough for most plants but to grow mosses and ferns really well, it's best to have temps of between 24 to 26°C. It's more for the plants than the fish.

why do you want to cool it to less than 24°C?

I want to see 22°C in my tank for the same reason Sir Edmund Hillary wanted to climb Mount Everest Because I believe it can be achieved.
The day the thermometer reads 22°C, I will turn the thermostat to set the freezer at a higher temperature. Even at 24°C like what the thermometer registered today, there's already condensation on the sides of the fish tank. Condensation would mean I can't see what's inside my tank but it feels good to know the tank is so cold. Here's a pic:

if you have some problems with the leaking fridge, then try to find the leaks and use some epoxid resin

I appreciate the suggestion but there's no need to use epoxy resin as the plastic bag I'm using to hold the water works just as well as using the compartment itself. As for using silicon, a friend told me silicon works well only with glass. He used it on a tank made with acrylic and the tank gave way after a few days.

The whole fridge should have a good isolation but you changed the cover and it looks really thin.

You meant insulation and not isolation, don't you, Robert? The cover I made for the freezer looks thin but there's a rubber seal on the insides along the perimeter. I believe it's quite effective keeping the warmth out and the cold in.

I already have a piece of styrofoam on the bottom of the tank. Almost every hobbyist I know uses styrofoam to keep their tanks stable. I also have a piece of styrofoam glued to the back of the tank. It's wrapped with aluminium foil. It's there because the back of my tank faces the balcony where the sun shines in everyday. The foil bounces the heat away from the tank. I don't think it helps very much but hey, anything for another degree



It rained today for most of the afternooon and evening. Room temperature now is 29.5°C. It should be a lot colder tonight. The temp of my tank now is 24.0°C. I turned the thermostat to its coldest reading as Wright suggested. I pray [-o< I can see a temp of lower than 23°C tomorrow morning.

Loh K L

[TyroneGenade]

Aren't there products that can retard condensation? I'm sure there is one that is used on bathrooms on tiles. I'm sure the principle is the same and it would work on glass. Any suggestions?

[RonWill]

why do you want to cool it to less than 24°C?

I want to see 22°C in my tank for the same reason Sir Edmund Hillary wanted to climb Mount Everest Because I believe it can be achieved

Guys, if the condensation isn't heavy enough, Kwek Leong won't have a reason to start on his DIY wipers!

The day when his tank stays at 24ºC, I'd want to see how his plants are doing. Then again, for someone with green wet thumbs, I doubt it would make much difference

The cover I made for the freezer looks thin but there's a rubber seal on the insides along the perimeter. I believe it's quite effective keeping the warmth out and the cold in

Still, I don't think it'll hurt to have a snug fitting piece of styrofoam between the bag and lid.

I suspect if you insulate both hoses connected to the freezer, with air-conditioning foam pieces, the temp should drop a tad more.

Willkommen Robert. The only reason I would want my tank that cold would be to maintain and breed cool water killies, never mind the plants! [but wait till the electricity bill comes in!]

BTW, where is 'north of Germany'... Bremen? or you're not residing within Germany?

[Robert]

Hi,
I know that the weather is always hot in Singapore. I have some friends in the Lion City and I visit a handful of your forums everyday (because the ambience is better in your forums than in ours and most of them are very informative for me). So I still knew why you built a chiller but I couldn’t understand why you want to have such low temperatures.
I got the idea of the insulation of your tank’s back wall when I looked on your pictures. I couldn’t see any insulation, just some paper which is not very effective. The idea of the better insulation of the fridge’s cover came when I read that you changed it and when I saw the picture of the new one. The new cover seems not to contain any coil and so it gives no heat up to the surrounding. But heat can come through it into the inside of the fridge, which influences the cooling-process. Perhaps there will be no difference if you use a better insulation but I thought it’s worth a try.


I kept some Aphyosemion striatum in the past and I had no problem with them at temperatures of 24-26°C. The only problem were their aggressions against my guppies. The female killed almost one of them and she used every chance to bite my guppies. The male was not that aggressive but he also bit my guppies every now and then. But I’m a guppy ( and dwarf shrimp) breeder and I need my males and females healthy and in good conditions, so the striatum pair found a new home outside of my tanks (I gave them to someone else).
A. striatum and A. australe (often you can only get the xantic form which is called “Cap Lopez” here) are the most common killies in our LFS here in Germany. But you still have to look for them, they are not as common as cardinal tetras or guppies.

Which species do you keep in such a huge tank? I always thought it’s better to keep killies in smaller tanks but you try to cool a 380liter tank, which is pretty huge for a killie-tank.

By the way, I live in a city in the north-east of Germany, in the state Mecklenburg-Westpommerania. Take a look at the map: http://people.freenet.de/r.gall/Germany.jpg to find it. It’s one of the most beautiful regions of Germany. We have about 2000 lakes (several hundreds of them are less than 50 kilometres away from me, it’s a paradise for fans of all kinds of water sports), lots of island in the Baltic Sea e.g. Rügen , our biggest German island and which is much bigger (975 square kilometres) than Singapore , beautiful fine white beaches and lots of pure nature with sea eagles and many other wildlife. Only the unemployment rate of 15 % (in the west of the state) till more than 30% (in the east) is a big problem for us. Now you should know a little bit more about me.
BTW Wright, I learned English at the grammar school and I wrote my A-level exam in English, too, because it was one of my two main subjects (the other one was biology).

I mentioned the colder water temperature for CR shrimps because many German breeders of this shrimp (including myself) experienced that you have much more egg-carrying females of this species if you keep them at 20-25°C. At 25°C and above most of them stop breeding and you get much less offspring. It is possible to keep them at 28-30°C and you will get some offspring but it is not as much as you could get at lower temperatures. I can watch this phenomena every summer when the room temperature reaches the 28°C mark (it’s almost the maximum which I can get in the room where the CR shrimp tank is). Fortunately our summer lasts only three months.

Best regards

Robert

[timebomb]

I always thought it’s better to keep killies in smaller tanks

Hi, Robert,

I'm quite sure that's a myth. Small tanks are favoured over big ones because Killifish enthusiasts always run out of space. I'm sure fish in general do better with more space. I have only a few Killies in my 380 litre tank. Just a couple of Nothos, a pair of Apistos and some Boraras spp.

The day when his tank stays at 24ºC, I'd want to see how his plants are doing.

Ronnie, the temperature hit 23.5ºC this morning but it didn't dip below 23ºC as I had hoped for. Anyway, I'm not sure about this but I believe the plants have been doing better since I fixed up the chiller. Here are some pictures of my plants:


The Downois seem to be producing more plantlets.


My Weeping Moss was all brown before I had the chiller


Not much difference seen in the Java Moss; they are one of the easiest moss to grow.


The Christmas Moss


The lower temperatures definitely help with the Willow Moss


My coconut with Java Moss growing on it. I'm hoping the pair of Apistos will lay eggs inside.


Can't remember which Moss is this but it's probably the Nano Moss which Gomer sent.


The most beautiful moss of all - Taiwan Moss

Loh K L

[TyroneGenade]

You see by ditching the chiller tank you have gained a degree. Didn't I say you would?

If you want those Apistos to spawn bury the coconut shell a bit so the entrance isn't so wide. They like privacy. What species do you have? borrelli? They like it cool.

tt4n

P.S. that Taiwan and weeping moss is really nice as is the Downois. Do they remain short like in the picture or get really busy and big? Back in SAfr we never saw such pretty plants.

[Piscesgirl]

The plants look great! I love all the Downoi!

[timebomb]

You see by ditching the chiller tank you have gained a degree. Didn't I say you would?

Yes, you did and I'm glad I followed your advice. Many thanks to everyone who gave suggestions and tips on how to improve the chiller. I'll be wrapping the filter hoses with insulation foam later.

If you want those Apistos to spawn bury the coconut shell a bit so the entrance isn't so wide. They like privacy. What species do you have? borrelli? They like it cool.

They are borrelli, I think but I'm not too sure. They're are my first Apistos. I'll see if I can get a picture later. They're quite big so I don't know if they will find the entrance too small if I bury the shell deeper.

hat Taiwan and weeping moss is really nice as is the Downois. Do they remain short like in the picture or get really busy and big?

The Downois don't grow very tall. Nid, in Thailand who grows them far better than I do uses them as a foreground plant. You can see a picture of her tank here

Loh K L

[Robert]

HI Loh K L,
thanks for the information and the nice pictures. I never saw such a huge collection of different moss species in a single tank before. I really like it. In Germany we know only java moss and Riccia fluitans and even these plants are very rare in the LFS, so it's hard for me to create a nice looking moss tank. Java moss is not the best choice and riccia makes a lot of trouble sometimes. I also like the Downois but I would like to know its scientific name because I never saw this plant before. I guess it's a Aponogeton species but I'm not sure.

best regards

Robert