Dear All,

Planning on using two Iwaki pumps for water return/circulation. Each one will be capable of the required flow and I was going to operate them alternatively (on timers) with different placed returns to the tank.

How tolerant are these pumps to being switched on/off and what would be the minimum time they could handle between oscillations?

Cheers.

Welcome to Reefland shaggss!

I don't think it is a good idea to run your return pumps on timers unless your going to be around when they are shutting on and off. Eventually one will fail and throw everything out of balance until the next cycle.

For alternating current see if you can get a rotating return device like the Sea-Swirl in your area. I'm not sure if they are distributed to Hong Kong.

Thanks Reefland,

Cheers.

You can also use a electrically controled valve that switchs the flow. The sea Swirls are less expensive.

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Paul C
Things should be made as simple as possible, but not any simpler.
Einstein

I am not sure with pumps/motors such as these but it is much more economical to leave the motor running in the industrial world. A motor pulls a tremondous amp draw at start up, to bring it up to speed. It is also very hard stopping and starting motors, atleast in the industrial world. That is why they make clutches, to keep the motor running. I think you will be much better off with sea swirls or electroincally controled switches to alternate the flow

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Paul C
Things should be made as simple as possible, but not any simpler.
Einstein

Still I dont think the wear and tear on the motor itself is a thing to shoot for unless you like replacing the pump motors yearly. [img]/ubb/lol.gif[/img] Now if you could purge the water from the pump before it was restarted I dont think its a issue. This would be similar to stopping and starting a table saw with a pc of wood cramed in the blade. It would eventually start but would require a longer ramp up time to bring it to operating speed, thus pulling a much greater draw for a longer time. Not only is this more expensive it is much harder on the motor windings. Not being a Electrical Engineer but a Design Engineer I cant explain why other than the obvious, the increase draw cause the magnets to wear out sooner, plus puts tremondous torque and strain on the other moving parts of the motor and pump. Just My opinion.

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Paul C
Things should be made as simple as possible, but not any simpler.
Einstein

Definitely agreed that Iwaki's are reliable pumps, however as Ltspd mentioned the motor will most likely not last as long as it would under normal operation. Buying two Iwaki's may not be the most cost effective option either. [img]/ubb/smile.gif[/img]

Big diffrence in a 15.00 ph and 250.00 pump [img]/ubb/rolleyes.gif[/img]

I am speaking on behalf of industry practices, of which I am very familar with, I deal with situations like this daily. I cant tell that there is any diffrence in these motors and the industry ones, small 1/6 hp motors are sort all the same except for mount style. Here is a link to industrial motors http://www.marathonelectric.com/ that you can read up on. There are invertor duty motors that can handle low rpm, stop and starting, but these babies are mucho bucks. I use the explosion proff Invertor duties, similar to black or blue max a lot.

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Paul C
Things should be made as simple as possible, but not any simpler.
Einstein

I find my corals prefer random current i agree good current is good but find if its random the corals seem to get some rest from current and seem to stimulate them more.turning the big pumps on and off every 1/2hr isn't recommended. just like big rigs or machinery takes its toll on and off. cutting 5yr off the life of a pump seem alot to me. I would opt for a sea swirl or just have stready current vs on/off

I believe that a motorized ball valve would be the best choice when compared to switching off and on flows. However this isn't the route I've taken, currently I'm using dual pumps one on recirculating spray bar and the second is on a 1" sea-swirl which equates to 2k gph. I'm currently collecting goodies for a new 240 system which will have a 4 swirls, 2-1" inch at the ends and 2 3/4" in 1/3rds mounted on the back.

starmstr,

Can you supply any info on the motorized ball valves please? The tank I'm planning is also around the same size as you are planning. The swirls are alittle more expensive to buy for me than another Iwaki.

Thanks.

http://www.haywardindustrial.com/

Here is a link to the company that makes the motorized valves.

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Paul C
Things should be made as simple as possible, but not any simpler.
Einstein

I use two from plast-o-matic. These actuators can use ball valves from 1/2" to 1" pipe, they have larger also, and are good for 1 million cycles. check them out at www.plastomatic.com

iwaki's The only way to Pump and Good to the Last Drop!

Got to love em.................nuff said!

Schottman [img]/ubb/spineyes.gif[/img]

here's another - don't know much about it, however
http://www.marin.de/salzwasser/engli...ber/eaqua1.htm

Thanks All for the advice,
Cheers