Powerhead Advice Needed

[mcgdz86]

Hey everyone

I was looking into adding some powerheads into both of my tanks and am looking for some advice. I am mostly uneducated when it comes to them; my basic understanding is that they can help add aeration and circulation to the tank, which is the reason I'm considering them. I could use some advice if they would be useful for my situation or if there's something better, and also what type/brand/power would be best.

The first tank is my brackish tank. It's a 37g bowfront that houses a Green Spotted Puffer and 10 bumblebee gobies. No live plants. It's currently freshwater but I'm slowly transitioning it to near full marine conditions.

I have it filtered with an Aquatop CF400UV Canister filter, which is rated at 370gph. I have both output valves pointed at the surface to produce surface agitation to pull oxygen into the tank. While the agitation is quite strong on one half of the tank the other half is pretty calm. So I'm concerned that possibly enough oxygen isn't being pulled in. I have no bubblers or other aeration system set up in this tank. I also worry that since both outputs are pointed towards the surface that the bottom portion of the tank is not getting circulation. I notice when I feed bloodworms they tend to just float straight to the substrate and sit there until their pecked off.

My second tank is a my freshwater community tank. It is a 37g bowfront as well that houses 1 Betta, 2 German Rams, 1 Molly, 1 Koi Angel, 2 Guppies, 2 Albino Plecos, 6 X-Ray Tetra, and a handful of Ghost Shrimp. No live plants.

This tank is hooked up to an Aquatop 300 Canister Filter rated at 264gph. I also have an Aqueon Quietflow30 HOB rated at 200gph. A Fluval Q1 air pump powers a large air stone in the tank. A believe there is plenty of surface agitation in this tank between the output of the canister, the HOB, and the bubbles from the air stone. I was wondering if some extra circulation in the tank would help... mostly to keep waste from settling on the substrate so the filter can pick it up easier.

Please let me know what you guys think would be appropriate for each tank. Thanks

 

[Jeroen]

I've bought a set of these recently.
with just a sucker instead of a magnet they get even cheaper.
http://www.aliexpress.com/item/resun-AquaSyncro-HWM-2000-Wave-Maker/2002316413.html

they're not ridiculously strong and for a reef tank it might be crap, wouldn't know.
But for my planted tanks they work quite well.
If there's species in the tank that don't like the heavy flow (I'd say puffers don't really) i tend to aim them towards the glass.

You can also set them up just beneath the surface to create a whirl and suck air in although when to close and too much air goes in this can get loud.
Lily pipe does the same without any sound?..

 

[PB_Smith]

If you understand what is happening at the water surface, than it becomes easy to develop ways to achieve what you want, with or without powerheads.

The exchange of gasses at the water surface is pretty much instantaneous and needs little help from us.
What we need to understand is how to maximize this to achieve as high of a rate of gas exchange as possible. not only do we want to gain oxygen from the atmosphere, we also need to release carbon dioxide and other gasses into the atmosphere.

There are three important considerations to meet to achieve the best results;
1: increase overall surface area for gas exchange.
2: do not allow any films or other layers to form on the surface which would impede gas exchange.
3: move the lower layers of water from the bottom of the tank to the top.

1) when we disturb the surface of the water and cause ripples, that increases the overall surface area available for gas exchange. Powerheads are good for this, but the same can be achieved with airstones and the returns from the filters, although not as vigorously.

2) oil slicks or a dust layer will interfere with gas exchange so the surface needs to be agitated to prevent this. Again, any means employed above will also achieve this.
Sadly many HOB filters that have the spill over type of return do not achieve this very well at all, nor do they disturb the surface enough for added surface area. you get a clean patch right around the filter and that's it.

3) exchange the water layers in the tank. This is probably one of the more important things as water at the lower levels of the tank will quickly become oxygen depleted if the tank has poor or no circulation top to bottom.
Basic rule of thumb in fish keeping, if you remove the water from the left, return it to the right, if you remove it from the bottom, return it to the top.
One reason I hate most HOB filters is because they spill the water right back to the intake spout and don't really move it around.
I did a "fix" that, I made an extension for the siphon tube from pvc and ran it along the bottom and over to the opposite side of the tank so water was being pulled from one side and returned to the other, but I'm getting sidetracked...LOL

Anyway, airstones are without doubt the easiest most reliable means of moving the lower water layer to the top, and it also causes an updraft current that helps keep the substrate clean. The only concern is with salt creep in the brackish tank.


My recommendation is try a small powerhead in the brackish tank and another airstone in the other tank at the opposite side and you should be fine.

Clean surface, good circulation and exchanging the water layers is most important, take care of those three and gas exchange will be fine.