Power heads in 75 gal.

I currently have an MJ 1200 and an Evo 1400 running in my tank. They're kitty corner to one another in the tank (close to the water line) with the EVO directed to the front glass. Last week when I did a water change I noticed a trace of cyano bacteria, mostly under rocks where the may not be much flow. It got me thinking that I may need to buy another power head.

How much flow is too much flow?

 

do you keep or are you intending to keep any corals


if your sand bed keeps being pushed, piled up leaving bare spots
if your corals fail to open properly as they seem to be holding on
if the polyps on SPS corals seem to be bending backwards on themselves as they extend

then you possibly have to much flow or more likely - to much water travelling in that general direction IME

the MJ is 1200lph or 400 gallons per hour and the Koralllia is 1400 gph - giving 1800 gph total

so you have about 24 times tank volume in flow
which is OK for a FOWLR tank and also good for a number of soft corals IME

Although
the Maxijet can be a pain without mods - as its a jet of water (ideal for reactors or returns on small set ups, but not ideal for pointing in the general direction of corals IME)

If I was going to have SPS corals at a later date

I would ditch the Maxijet and get another Evo 1400

this would then be 2800 gph and 37 times tank volume in terms of flow
but in a form that much easier to distribute due to the wide spread of the Evo wavemaker

if your not getting corals or particularly SPS corals
then adding another smaller wavemaker lower down and angled towards the cyno problem spots, but not so pointed as it kicks up sand, may help relieve the cyno issue for you

but in addition to more flow, removing nutrients Via GFO in a reactor ( a great purpose for that Maxijet IMO) would also be a good idea

Steve

 

On my 75, I have two K4's (1200gph each). One in each baCK corner & a modded MJ900 that's directed along the face of the rock. Flow has been much better since I added that MJ recently.

 

right now i have 2 Koralllia 1400 and 2 750's in my 75gal and have a mixed reef and havent had any issues my clowns actually love the flow.

 

I don't currently have corals but I'm perhaps getting some in the next couple of days. My sand was moving around at first but since I pointed to the Evo to face the front of the tank I haven't seen the sand moving as much

 

I pointed 2 of mine towards the top so it breaks the surface and then one to move the water in the back and one in the front. What kind of sand do you have?