A couple of questions

[Mr_Cool]

First:

Is it just a fluke that I don't need a heater in my 55 gallon tank? All summer long, my temp stays around 80-82 degrees. In the winter (like this time of year) it's at 78-80 degrees. I don't have a heater. I guess I should probably get one just in case the power goes out. But, even then, the fish and corals would die from lack of oxygen rather than the cold. Is it just that the tank is small enough or what?

Second:

What's the deal with calcium? I don't keep sps corals, so I guess Ca is not a big concern of mine. Should it be, though? I have some soft corals, but that's it. Is dosing with Kalkwasser (sp?) just a way to increase or maintain the calcium level? Same for the Ca reactors? And, just what is Kalk anyway?

I see this stuff all the time in these forums. Just thought someone could fill me in.

[Richard]

First:

Is it just a fluke that I don't need a heater in my 55 gallon tank? All summer long, my temp stays around 80-82 degrees. In the winter (like this time of year) it's at 78-80 degrees. I don't have a heater. I guess I should probably get one just in case the power goes out. But, even then, the fish and corals would die from lack of oxygen rather than the cold. Is it just that the tank is small enough or what?

That's not unusual. I still recommend a heater to keep the temp stable day/night. Daily temp fluctuations can sometimes lead to some problems with protozoan diseases.

Second:

What's the deal with calcium? I don't keep sps corals, so I guess Ca is not a big concern of mine. Should it be, though? I have some soft corals, but that's it. Is dosing with Kalkwasser (sp?) just a way to increase or maintain the calcium level? Same for the Ca reactors? And, just what is Kalk anyway?

Kalk is calcium hydroxide also called limewater. It is a white powder that when mixed with FW creates a saturated solution that will provides calcium and support alkalinity. It has to be added slowly as the ph of the saturated solution is very high ~12. You still want to keep your ca at a reasonable level maybe >350. B-ionic might be a better/easier solution than dripping kalkwasser.

[Mr_Cool]

Thanks Richard. I think I'll pick up a heater. But still, doesn't the ocean temp vary a little from day to night and from one day to the next? I guess it must be the comparatively miniscule volume of water in a fish tank that make all the difference.

[Bill S]

Temperature variations on shallow water reefs can be HUGE. For some reason, this hobby seems to think they are constant - and they are not. That being said, our tank inhabitants do MUCH better if we don't stress them with temperature swings - get a heater.