Spray Bars

Hi,

I'm hoping that someone can help us settle a domestic ...

We have a spraybar for our 15-gallon tank. The last time we used this for the return flow from our submersible (clearjet 1) filter, the tank developed a bacterial bloom. Now we want to reintroduce the spray bar, but are having some 'issues'

We'd be interested to know how others have their spray bar set up, why, and if there have been any problems with it. (I'm not telling you which of the following options I favour, so as not to bias you )

One option is to have the bar above the water, trickling down the wall of the tank, to minimise flow - but we think this might encourage a return of the bloom.

Another option is to have the bar above the water, spraying into the surface - this may encourage oxygen to dissolve by breaking the surface, restricting bloom, but might be excessive flow.

The last option is to have the bar in the water, spraying just under the surface of the water, so as not to break the surface, but this may induce excessive flow.

Currently, we have a compromise in which the bar is partially above and partially below the surface of the water. It'd be ironic if that's the best solution...

I will cast my vote, but my situation may be very different from yours. All my tanks have screen lids, and since I moved to a dry climate evaporation is a problem. A spray bar above the water would increase evaporation, so I don't do that. I have my spray bars under the water, with the spray pointed toward the glass or slightly upward. I haven't noticed any problem with current, but my filters with spray bars are not very powerful (Zoomed 501).

The question I would have is when did the bacterial bloom occur in relation to when the tank was originally set up?
Ed

About four months after the tank had been cycled, and about a week, perhaps two, after introducing the spray bar.

Hmm, very interesting. Did you by any chance do a very large water change at the same time?
Ed

Not that I recall. We did perform a large water change in an attempt to rid the tank of the bloom, but that didn't work. I'm starting to think we should keep better notes

Thanks for your response by the way Jennifer. It's pretty damp where we are, so much so that we tend to have a dehumidifier running somewhere in the house at any one time - as you guessed, evaporation is not our problem

Since the spray bar return was reintroduced, our axolotl in the large tank (as opposed to the one recuperating) has rediscovered the joys of plant-climbing. It's hard to tell, but he looks happy about it...

Large bacterial blooms are usually the result of a disruption of the aquarium cycle resulting in a buildup of nutrients spiking the bloom.
The two I mentioned are the most common causes of blooms but removal of an old filter and setting up a new one is another possibility. But occasionally it just happens.
Just some thoughts,
Ed