Powerheads question

Anfo42 · Oct 31, 2014

I'm quite confused with the whole gph thing for my 29g. The 29g was given to me as a gift and I was told that they had an 800gph and a 400gph power head in a tank that kept sps and softies. I would like to have a reef tank and recently finished my cycle. My water is great, everything checks out and I purchased a hydor koroli 850 thinking it would be sufficient. this thing looks to be a bit powerful for medium flow. I have it at the top pointing upwards for water agitation now and it has slowed the flow a bit in the rest of the tank however, it still seems a bit powerful. before I had it placed lower in the tank and it was making a somewhat hurricane effect in one spot of the sand bed. My dad got me a clown since my water was finally good to go. The clown loves to swim right where the powerhead is and get launched upward... does the 850 seem to be a bit powerful for my future reef set up or should i swap out for something a little less powerful?

Reefing Madness · Oct 31, 2014

Ok, so heres the deal.
Reef tanks flow start out at 20x your DT volume. So for a 29g tank you'd be ok with just 600gph, or using 2 300gph powerheads. Now that being said, SPS love high flow, and you really can't have to much flow when you run an SPS dominate tank. Softies and some LPS will get ticked off if they get blown all over the place. SO, is yours to high, not really. You could break that flow up, and use 2 400gph powerheads instead of one giant one.

Anfo42 · Oct 31, 2014

Thanks! I didn't know that there was a formula. I hope I can return my powerhead and get 2 smaller ones.. I really like the hydor koralia Evo I have, it's super quiet.