2 Koralias 750 too much for a 30 gallon ??

Yes. You can. I had a 750, 550 and 450 in a 14 gallon cube with areas of low flow for zoas. It takes some tweaking but flow is a MASSIVE part of the reef. It brings nutrients towards and away from corals. SPS without a doubt grow much faster and have better polyp extension in high flow. For example, I put a frag of pink birdsnest in an area of high flow (about a foot away from atleast 1500 gph) and a another frag of the same birdsnest in an area of low flow (less than 100gph estimated) and the one under high flow grew twice as fast. This is just my experience but I think most reefers dont have enough flow in their tanks. Not even close.

That should not be the case in my opinion. Do you use fine sand? I always use crushed coral as a substrate to avoid the sand moving around in the tank.

 

Try doing what i did in my tank! place them in the rear corners facing the front middle! It creates a nice wave like effect and has nice high/med/low flow areas!

 

I have a 550 on my 30 and it almost killed my Xenia. Ya that's right.. A Xenia. I'm not sure what happened but it sure wasn't right next to it. Just be careful.

 

Exactly! By pointing all the powerheads towards the center you can create a point of turbulence making for more random flow. I forgot the exact statistic, but studies have shown all the water on most reefs is replaced more than twice daily. We are talking millions if not billions of gallons of water.

 

Sadly I mad a big time mistake and used sugar sand. It's sugar sand mixed with 1-2mm sand. The 750 made big time dunes.

 

Simple rearranging of rocks around can easily create lower flow areas,using the rock as flow reducers along with proper placement of corals.If you can arrange them to get your sand to settle down,i'd vote on keeping them as well.

 

You can also see if just one can provide the flow you want vs. just going out and buying more powerheads.

 

Well that was kind of an experiment... lol I had them laying around and wanted to see how the tank reacted with all of them after reading about flow on the reef. Simple rock rearrangement and creating a point of turbulence will do wonders in a tank.

 

I'm currently have two 420gph powerheads in that tank(one being the return pump) I'd love to bring in the 750.

Sorry to hijack guys, if anyone has anything regarding my issue feel free to pm me so that we don't steal this thread.