[liquidkiwi]

Good day!

About 5 weeks ago I started a new, 200L cichlid tank. The tank was fully cycled (as informed by the LFS owner after a water test, ammonia at zero and nitrite at zero) after housing 4 Electric Yellows for 4 weeks. At this point I added 4 Sunshine Peacocks. This happened two days ago.

So today I did a 30% water change, the first change since starting the aquarium. This left a few questions on my mind so I thought to ask the experienced folk here.

During the water change I had to turn off both the heater and the pump (both would have been partially above water level during the water change). From what I've read, the beneficial bacteria in the filter media starts to die as soon as the pump is off because of a lack of oxygen. The dying bacterial colonies in turn pollute the water and can cause great harm to fish.

That, combined with the dropping temperature of the water leads me to believe that this is a very real thing to be worried about. This is a hard question, but how long can the filter remain off before the bacteria start to die and affect water conditions? Wouldn't this also 'undo' the cycle which we all aimed to complete in the first place?

This is also important because on the very odd occasion, we get brownouts and blackouts in our area. The last one was after strong winds hit and we were out of power for as much as 6 hours.

Naturally after replacing the water I dosed the whole tank with a solution purported to contain beneficial bacteria, in an aim to restore the balance. Something tells me that I'd be spending a lot of money on bacteria in the lifetime of this tank.

Next question relates to the cleaning of gravel. I bought one of those standard gravel cleaners when I started up. It's a simple plastic hose but is connected to this thingamagig that is wider on one end. It whisks away dirt very effectively without sucking up the gravel itself.

The key issue is that, being a cichlid tank, there is a fair amount of rockwork in it. There are two man-made caves constructed out of over 10 rocks each that took me hours to make and ensure they were stable enough.

With the rocks in the way there's a fair amount of gravel that my gravel cleaner/ siphon cannot get through to vacuum the gravel, unless I want to risk disturbing the rocks and causing them to cave in and kill my fish...how should I go about removing the faecal material in these areas?

Ultimately I resorted to simply doing a quick siphon of water from the middle of the tank where it was clearest, and replaced the water before temperature dropped too low. Temperature in the house gets a little low during the day and the tank started cooling down the minute the heater was off.

Besides that, the fish seemed to enjoy the water change, coming out to explore my hand and the gravel cleaner, and even emerging to swim in the massive current that must have developed when fresh water was being added. They're all happy now and barring any major stuffup I hope to still have 8 fish alive tomorrow morning.

 

[DJRansome]

how long can the filter remain off before the bacteria start to die? Wouldn't this also 'undo' the cycle? blackouts for as much as 6 hours. I dosed the whole tank with a solution purported to contain beneficial bacteria

Two hours while you vacuum the gravel and scrape the glass is not a problem, no need to add bacteria with every water change. Six hours if the filter material remains wet is probably OK too. Yes if the bacteria dies you will have to cycle, plus the decaying bacteria itself can pollute the tank.

there's a fair amount of gravel that my gravel cleaner/ siphon cannot get through to vacuum the gravel,

Use a clean turkey baster to blast debris out of rockpiles. Realize you will have occasion to remove the rocks since you may have to net a sick fish...just not every week.

Temperature in the house gets a little low during the day and the tank started cooling down the minute the heater was off.

Attach heaters so one or more is submerged below the waterline even during a water change.

 

[liquidkiwi]

there's a fair amount of gravel that my gravel cleaner/ siphon cannot get through to vacuum the gravel,

Use a clean turkey baster to blast debris out of rockpiles. Realize you will have occasion to remove the rocks since you may have to net a sick fish...just not every week.

Temperature in the house gets a little low during the day and the tank started cooling down the minute the heater was off.

Attach heaters so one or more is submerged below the waterline even during a water change.

Thanks for the advice. Looks like I might be in for shifting the heater everytime I do a water change. However it's good to know that a little bit of downtime might not really damage the bacterial colonies.

I'd hate to have to undo those two caves and reconstruct them again, especially with all the fish still in the tank. But when the time comes I guess it's not a matter of choice. I'd have to look into the turkey baster. :wink: The other thing I tried doing was to disturb the gravel and get everything floating in the water before doing a siphon. But usually a good deal of it sinks back into the gravel before I can get to it.