# Building a custom Spray Bar??



## RyanRX7 (Mar 22, 2010)

I have a 125 and had imagined making a tank length spray bar, and hiding it inside the 2" rim of the tank. The pump driving my filter set-up is an Iwaki MD-70RLZ pressure rated pump. It delivers about 600gph to the tank. Having never used a spray bar, I'm curious as to weather that 600gph would suffice for one 6' long? If so, any ideas on size and spacing of the holes? I had imagined to put them facing slightly toward the glass as to circulate the water down, across the substrate, and back up. I have another Iwaki MD-40RLT no pressure rated pump, that's about 800gph at 0 head. Not that I would swap it for the other, the head pressure would have it to a trickle before it got to the tank. Just throwing it out there incase anyone has a clever idea that may involve it. I'm trying to avoid having any power heads inside the tank if I can help it. The tank is viewable from 3 sides and I have only the left side tank wall to work with as far as routing pipes up to the tank.

As always, thanks so much for the help.


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## Diana K (Dec 20, 2007)

I would start with just a few small holes and work up with more holes. If you reached a point where there were enough holes, but the water was still coming out with a really strong blast, then make the holes larger.

Maybe start with two dozen holes with 3/16" drill bit. Spread out equally. 
If there is any way at all of having the water enter the spray bar from the middle that would be much better. More even distribution when you start reaching maximum quantity and size of holes.

Another trick would be to use a smaller drill bit close to the source and a larger drill bit at the far end.

Fortunately PVC pipe is cheap, and thin wall is really easy to drill. Try several layouts and let us know what happens.

From a site that sells the Iwaki-MD-40-RLT, and they have charts that back this up:


> The Iwaki RLT type aquarium pumps handle back pressure better than RLXT pumps and can be used for almost any application. They are recommended for high-head situations or when using cartridge (pressure) filters. The MD pumps have Japanese motors.


However, based on your comment of 'no pressure'...
I can think of only limited use of a pump that will move fluids only when there is little or no pressure. How about as a power head? 
Or, if you have an inlet and an outlet of the same length will this pump 'think' there is no pressure, because water that falls downhill from the supply side is equal to the distance for the water to go back up hill to return to the tank? A canister, but as little hose and fittings as possible, and no media to get in the way. Looking at the web site, it looks like this is a dry mounted pump, with closed inlet and outlet. Is yours intended only for horizontal movement of water?


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## Diana K (Dec 20, 2007)

As for 600 gph for a 125 gallon tank... that is about as low as I would want it. Fine for plants, CO2... and fish from slow moving water or lakes. Not nearly enough for fish from a fast moving river or an active mountain stream.


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## RyanRX7 (Mar 22, 2010)

Some very good ideas, thank you for taking the time to post them.

It was bad wording on my part to say the pump was "no pressure". They are both in fact rated for various degrees of head that they can handle.

The pump that I'm going to use to drive the spray bar and my Ocean Clear canister filter (incase you're unfamiliar, they are a stand alone canister without a pump) is the Iwaki MD70-RLZ. It is a dry pump, and the reason I chose it was it's ability to deal with a max head of 66 feet. I figured that after pushing the water through the canister filter, then having to deal with all the various fittings I would be in the neighborhood of 20 feet of head. At that head the pump should be at about 600gph.

The other pump I have is the Iwaki MD-40RLT. It's dry as well, and can only handle a max head of about 21 feet. At 0 head it can push about 800gph, but the 20 feet I'm guessing would have it to almost a non-existent trickle.


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