Mapping Water Currents in My Aquarium

[ChrisD]

I'm trying to come up with a method to map the water currents in my aquarium. I think it'd be cool to both come up with a method and to see the results.

I only have an in-tank filter and air stone- no supplemental circulation pumps.

My first experiment is going to involve putting some sort of flag on the end of a stick and methodically moving it around the aquarium.

Anyone else have ideas?

 

[Daniel]

Non-toxic dye or little neutral buoyancy plastic beads or fish food would work also.

[Spewing_nonsense_]

1 hour ago, Daniel said:

Non-toxic dye or little neutral buoyancy plastic beads or fish food would work also.

Yeah that was my thought was food dye that’s non toxic, dropping it right in front of the filter and see where it goes

[ChrisD]

Well, my filter has a spray bar (Denerle Eckfilter), so I can see the outflow. I'm more interested in seeing the flow in the rest of the tank- the course water takes to the filter inflow.

I would think food dyes would instantly dilute and thus not last long enough to allow tracking.

 

[Aubrey]

Whenever I feed the Co-Op fry food, I spray it near the out flow of the HOB. It's easy to see the flow as it sinks and I can see how far from the filter it goes from how much lands on plants and hardscape away from the filter.

Another way I have observed flow is by using a strong focused LED flashlight at night with all other lights off. Usually there are particles free floating in the water and they are made much more visible in the beam from the flashlight. Just point it straight down on the water.

Edited October 18, 2020 by Aubrey

[tolstoy21]

The folks at bulk reef supply publish flow dynamics of many of the pumps they review.

I have no idea what they are suspending in the water in their videos, some kind of beads, but whatever it is it gives one a good visual of flow patterns. Not sure one can do this kind of experiment with live stock in the tank, but could give you some ideas  

Here’s a video they did illustrating the flow pattern of a gyre pump around hard scape to show dead spots, flow dynamics, etc.

 

[Dandy Pearl]

I like your 'flag on a stick idea' as it does not put anything in the water and is reusable.

What about tying a long piece of colored thread to your stick. The flow should carry it and you should be able to see more of the flow at one time. you could even use several threads at a time.

Good luck!