Plumbing Questions

[MKCindy]

Ok, need a second opinion, am I over thinking this?

I am hard plumbing my new overflow. It has 2-1 inch over flow hoses from a 7 x 3 in. gravity feed weir with a siphon pump in the top to prevent air pockets. So, if I get this, each hose moves 300 gph, 600gph total. (or will the siphon pump increase the flow) The return pump needs to move 600 plus a 5 foot pumping height. So, I ordered this Mag 12 (major Tim the Tool Man Syndrome), guess a Mag 9.5 would have been plenty, right? (approx. 800 gph at 5 feet)

So now, when I put in the cut off valve on the return line, should I use tubing or hard plumb it too? Mag 12 requires a 1 1/2 in. isd. If I hard plumb, where do I get a 1 1/2 in. return U-Tube, or do I need to hard plumb all the way over? What paint works on white PVC?

[dustint21]

You can do your puming either way! I would hard plumb it! I dont know why you need the bigger you tube. Krylon fusion paint for the plastic! The Mag 12 is pretty big! But the 1.5'' Hard plumbing should help cut down on it a bit with the 5ft span! Good luck!

[mattymalcolm]

I tried the soft hose and had problems> my opinion is hard plumb all the way.

[MKCindy]

Thanks.

The instructions say "1 1/2 in. isd is minimum hose that should be used for maximum flow"
So can that be interpreted to mean I can use smaller if I need less flow, but wouldn't a smaller hose create more pressure, thus faster flow? (Physics was over 30 years ago, but something is dinging up there)

The box says 3/4 in. FPT Inlet and 3/4 in. MPT Outlet. The actual opening is 3/4 in.
I would much rather use 3/4, but what is the deal with 1 1/2 ? I just don't want to be mopping floors.
Or does it mean faster flow, but not as much volume per hour. (Maybe, I'm having a light bulb moment here.)

[Bill S]

When you put bends in your plumbing, it really needs to be a larger diameter. Since the mag pumps aren't pressure pumps, when you restrict flow at all, it slows it, it doesn't make up for it with pressure. If you hard plumb, use 1.25 or 1.5. if you use tubing, you should be OK with 1". 1" has 2x the flow of 3/4" (diameter squared).

In any case, don't use 3/4". You won't be happy...

Oh yeah. Plumb in a couple of rubber couplings. HD sells them. they will keep your pump noise down by isolating its vibration away from the rest of the hard plumbing (assuming you hard plumb).

[alton]

I had a Mag 18 on my 75 oceanic reef ready and it only had 1 - 1" drain and a 5' lift on the return. So your mag 12 should be fine.

[MKCindy]

Thanks that helps a lot.

[himegs]

Ok, need a second opinion, am I over thinking this?

I am hard plumbing my new overflow. It has 2-1 inch over flow hoses from a 7 x 3 in. gravity feed weir with a siphon pump in the top to prevent air pockets. So, if I get this, each hose moves 300 gph, 600gph total. (or will the siphon pump increase the flow) The return pump needs to move 600 plus a 5 foot pumping height. So, I ordered this Mag 12 (major Tim the Tool Man Syndrome), guess a Mag 9.5 would have been plenty, right? (approx. 800 gph at 5 feet)

So now, when I put in the cut off valve on the return line, should I use tubing or hard plumb it too? Mag 12 requires a 1 1/2 in. isd. If I hard plumb, where do I get a 1 1/2 in. return U-Tube, or do I need to hard plumb all the way over? What paint works on white PVC?

Sounds like you have the exact same situation I had with a tank I am setting up. (I'm a few steps ahead of you.) The Mag 12 is going to push too much volume for that overflow, so the way I see it you aren't concerned about maximum flow - especially if you're using the valve to shut it down a little anyway. (If I mis-read your intentions, then it might be a different story.)

I have a 50 gallon semi-cube, and I hard-plumbed with 3/4. It is giving me more than enough flow for this size tank. I had to work to keep it from digging holes in the substrate as it is. I may put in a Koralia, but only to move water in a hard-to-get-to area, not because there isn't enough movement in the main area of the tank.

Personally, I don't think I would like the look of a 1 1/2" return u-tube coming over the back of the tank. If you are going to try, Lowes has 1 1/2" p-traps that would make a single-piece U, rather than using two elbows. I would definitely hard-plumb the valve, rather than using tubing.

For the record, I set the overflow aside and had the tank drilled. Two overflow tubes are just more things to worry about and fiddle with.

[MKCindy]

I've decided to hard plumb with 1 inch. The p-trap is a good idea. I am thinking of drilling holes or slits in the return to reduce the flow onto the sand bed or if I use a U tube I can add a deflector. I am presently using 2- Kor 4, but I think I'l only need one after the conversion.

[Mr Cob]

<quote>What paint works on white PVC?</quote>

Krylon Fusion spray paint is made for outdoor plastics...so that should work perfect on PVC.

[brewercm]

Sounds like they've pretty much covered you on all of this. Didn't read through all the post so sorry if this is repetitive but a 90 degree bend in your hard plumbing equals about 1ft head loss as far as these pumps go. Also don't confuse volume and pressure, when you increase pressure you decrease volume which is what a pump is rated at straight out of the outlet (normally).