High Aquarium Temp

[Sanj]

Hello,

I know we have recently had a bit of a heatwave here in the UK, but the temperature has since gone down a bit, the problem is my aquariums have not, they are both at 31C in the day and 29-30C at night!!

The heaters arent on, they are set to 24-25C.

Could it be that the aquariums just take a lot longer to respond to atmospheric changes, considering the lights probably also add to this heat??

I have recently conducted water changes and since that have lost several fish in my Rena aquarium, tested water and quality from Ph ,Ammonia, nitrites, Nitrates is very good.

Im a bit stumped??

 

[canarsie11]

Do you have an airstone or plants in your tank? Less oxygen in the water because of the heat. That could be reason for the loss of fish

 

[Sanj]

Yes the tank is failrly heavily planted, it just has an external filter there is good circulation, but not too much surface disturbance. I thought about oxygen starvation, but the tank isnt really very heavily stocked considering its size.

 

[Aquascaper]

Everything has what's known as a 'latent heat capacity'. The specific latent heat of a substance is the quantity of heat energy required to change the state of a unit mass of a substance.
Things with a high latent heat capacity will take a long time to heat up (and use up a lot of energy) but will lose heat very slowly.
Water and rocks both have a high latent heat capacity and therefore take a lot of time to heat up (think of the sea - it's warmer at the end of summer than at the beginning) but cool off slowly.
When you first set up your tank you would have noticed the heater on almost constantly for a day or two, now I bet you hardly see it on for more than a few seconds.
It's the same with rocks, you heat them in the oven to sterilise them then have to wait ages for them to cool before putting them in the tank (People used to warm rocks by the fire before bed to use instead of hot water bottles as they would stay warm most of the night).
Because of this it's rare to get quick fluctuations in temperature and therefore hard to change the temperature quickly (unless you do a water change).
Canarsie11 is right that higher temperatures reduces the level of oxygen in water and this could be a cause of the problems you're experiencing. You may find that it is as simple as the fish that are dying just can't tolerate temperatures of 30c - 31c (very few fish can for long).

Try floating a plastic bottle of water that has been in the freezer in the tank, that should help a little. Another tip is to set up a fan to blow over the surface of the water to increase evaporation and heat loss (you will have to top the tank up more often though).

HTH

 

[Tenko]

I lost a few fish due to excessive heat at the start of the summer. I messed about for weeks trying to cool it off.

I left the hood open a little to allow evaporation, unplugged the heater and severly restricted the time the ligts were on. I also froze blocks of dechlorinated water which I'd place in the filter housing when it rose too high. This only consistently reduced the temperature by a degree or two.

In the end I had to buy a cheap air conditioner, £120 from B&Q. Although to be honest, it wasn't just for the fish's benefit as their tank is in the bedroom. Now the temperature hovers around 24 all the time and the fish look a lot happier.

It was expensive, but worth it.