# Current



## ranha-man (Oct 14, 2011)

...About to buy a Hydor 750 powerhead with a timer hookup. What is the preferred time schedule for the powerhead to be on/off?


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## Ægir (Jan 21, 2006)

My rhoms powerheads (3) MJ1200s come on when the light do, and off at the same time. 1 more and a 1500GPH return pump are always on... This is in a 120gal tank, and they are pointed so the flow is from one end of the tank to the other. I will also add that its not good for powerheads to be switched on and off... the "crash" of starting the impeller (unless you are using a controller or timer with "soft start" to ramp up) breaks things fast. once per day isnt bad, hour or half hour cycles arent going to help the life of the pump.

Some fish like the current and swim right in front of the powerhead, some hide when it comes on for a while... how much flow really depends on the fish. The amazon river is high volume, but because of the huge width only flows feet per day in some places.


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## ranha-man (Oct 14, 2011)

"I will also add that its not good for powerheads to be switched on and off... the "crash" of starting the impeller (unless you are using a controller or timer with "soft start" to ramp up) breaks things fast."

Where can I find a timer switch with "soft start"?


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## Ægir (Jan 21, 2006)

Hydor makes one for the Koralia pumps... but they are like 200$. What size tank is this for? why do you want to shut it off or switch it?


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## ranha-man (Oct 14, 2011)

"Hydor makes one for the Koralia pumps... but they are like 200$. What size tank is this for? why do you want to shut it off or switch it?"

This is for a 90 gallon tank. I want to shut it off and turn it on to give the fish a break, because I can't figure out any creative ways to give my tank a dead zone for the fish to relax.


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## Ægir (Jan 21, 2006)

In a 90 gallon, 750gph isnt "lots" of flow (unless you have a huge sump and return, or a FX5 canister?) to have on the entire time. If you are worried I would just put it on a timer with the lights, and when the fish grow a little more put it on full time!

You have 11 reds in the 90 gal? how big are they now?


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## ranha-man (Oct 14, 2011)

"You have 11 reds in the 90 gal? how big are they now?"

No. I only have 8 of my reds in the 90 gallon. These 8 are a little over an inch. Ik all about the # of piranha per tank and everything. Once they grow a little they may get a bigger tank.

My other three reds are in a different tank and they're about 6 inches.


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