I own an established planted 36BF that has been running for 1yr. It has several Anubis Variety as well as some amazon sword plants with rock and Driftwood. I keep my aquarium @ 80° Fahrenheit.
I am running 2 Classic Eheim Canister filters Model 2217, 1 Fluval Heater & a newly acquired Maxi-Jet 400 powerhead to keep the plants free moving from an algae takeover.
While adding the powerhead on 2/11/14 pointing to the right side of the aquarium (mid Tank) with the spray bars facing up to agitate the water above pushing the flow toward the front of the aquarium My Cardinal Tetra's as well as the pair of German blue rams were ALL gasping for air!
I quickly unplugged the powerhead and proceeded to rotate the spraybars Up to agitate MORE water an added an airstone right away. I lost 4 Cardinals total R.I.P. (out of 14) Saved both rams as well as the other stock list I had in the tank currently which was 2 Cory's, 2 Otto Catfish, 1 Bristlenose Pleco & a Pair of Threadfin Rainbow Fish. Lucky I caught it!
Here is a picture of my aquarium.
Where the powerhead is attached, I get optimum Flow (The plants sway back & forth, NOT violently with NO surface agitation mind you) I wanted optimum flow for algae control, however once I added the powerhead, my fish almost died, gasping for air at the top of the tank!
A picture of my current flow on top of aquarium.
As you can see, the water agitation is more on 1 side of the tank then the other For Now. (See #1) I had it like this BEFORE adding the powerhead and the fish were happy, all breathing normally. Even now. (Present) all fish are fine without using the powerhead.
(#1) I'm breaking the filter down. It's stuffed with a mixture of Eheim Cocoa Puffs and the other that looks like white coarse rock. NO FLOW.. Adding 3-4 Blue coarse filters then Pillow stuffing then that mixture. OR, All 6 Blue Coarse filters then pillow stuffing.. I don't know. Need more flow from 1 of the 2 eheims I own. Other is filled with a white coarse sponge, pillow stuffing then the knock-off of Fluval BioMax. Tank is *Crystal* as a Bell. SO. Why are my fish not being able to breathe?
I would like to add C02 injection. The only thing I figure is since I added the powerhead to the aquarium and the fish swam to the top of the tank gasping for air, that somehow by running the powerhead, it deprived the fish of oxygen. Don't plants release oxygen into the water?
In theory, once I add C02 injection, I will be able to use the powerhead where It is. The spray bars, agitating the water on top, oxygenating. I just need to purchase and attach a drop checker within the aquarium that measures the C02. THEN I can give the plants & fish the correct C02 the aquarium & fish truly need to flourish? Have I got it?