Temperature - How high is to high? And effect or considerations on Chemestry

[Clown2020]

Hi

I currently have a 32 gallon fluval flex with a fair amount of coral mostly LPS some SPS and Soft, hadn’t given much thought to a chiller until I noticed my temprature starting to climb on hot days. at its hottest the tank will run at 28.5 Celsius over a 5 hour period. So far I have not noticed any impact on the coral and seneye is showing the temperature change both up and down to be gradual.

What would you consider to be the maximum safe temperature and are there any impacts or things to think about with regards to water chemestry given the tank is running at a high temperature?


Thanks

 

[shwareefer]

28.5 would be as hot as I would want it to go but 30 would be the red line where you should float some ice bottles...

 

[Randy Holmes-Farley]

Running a tank at high temps does lots of things to the creatures and how fast they metabolize and such, but the main chemical thing it does is drop the O2 a bit (driving it out of the water into the air), If you want to run hot, I'd be sure aeration is kept high.

I kept my tank temp lower in the summer to give more buffer against temp rises if power failed. I usually aimed for about 80-81 deg F.

 

[Clown2020]

Thanks, Running hot wasn’t my intention but wil be the reality for this summer provided it doesn’t get any hotter as a chiller isn’t something I had considered and is quite expensive here. Denifnitly gonna have one for next summer and run 25 Celsius all year round

Good to know about O2 wave maker and return pump create good movement on the water surface so should be good their


Does less O2 mean there will be higher CO2 in the water?

reason I ask is overnight ph always drops to 7.5-7.8 (7.8 with a window open) as my tank has started to mature over the last 7 months and as I have added more coral my peak ph is 8.2-8.3. Unfortunately running an airline outside is not an option for me. Alk, Ca, Mg are all at the higher side of normal

will the temp combined with ph have any impact?

 

[Randy Holmes-Farley]

Does less O2 mean there will be higher CO2 in the water?

No. CO2 and O2 do not impact each other in water. They can move independently.

The effect of temperature on the pH of seawater is complicated and small in the range experienced by reefers. Temperature impacts not just CO2, but other acids and bases in the water, such as bicarbonate. It is a stronger acid at higher temperatures.

 

[PatW]

Increasing temperature has a double whammy. It increases metabolic rate and decreases O2 solubility in water. I dive and I have seen healthy reefs at 84 degrees but if it gets much higher that can be really, really, really bad for the corals. Coral reefs can do fine at much lower temperatures. Temperatures in the low 70s are well tolerated and even lower.