Has this been tried?

[HighlandReef]

what i have been wanting to try is an overhead closed loop that basically sits on the top of my tank, i have a fish room so you wouldnt see it from the other side and running off my manifold from the sump but again if your tank is not behind a wall that prob wouldnt work as well

 

[tufacody]

I thought of that too CG, and looks like I might give that a try. It will probably need a priming tube if its above the tank.

As for pulling water out of the overflow box, that is true, but wouldn't it just flow over all the faster? That water has got to go somewhere. Its the draining down to the outlet that worries me.

Ultimately I'm just trying to please my gigantea, which is doing ok but I think it could be better. I went to the MN zoo last weekend and their surge tank with cold water nems was really cool. I've looked at the homemade surge systems but don't want to deal with that. Plus they are ugly and I can't conceal one. If I can't safely incorporate something that can recreate a better surge I may just have to try a wavebox.

 

[evsalty]

<a href=showthread.php?s=&postid=15475067#post15475067 target=_blank>Originally posted</a> by CGRANT
what i have been wanting to try is an overhead closed loop that basically sits on the top of my tank, i have a fish room so you wouldnt see it from the other side and running off my manifold from the sump but again if your tank is not behind a wall that prob wouldnt work as well

So you would be feeding a pump for your closed loop off your sump return pump? IMO that wouldn't be a good idea. You would have to match the CL pump to how much water is being fed to it or you risk cavitation or having it pull too much of the return water.

If not that and just a closed loop with the pump above the tank you would need to either use a special self priming pump or would need something to keep the power off after power outages until you personally can reprime it and restart it.

 

[addicted2reefin]

<a href=showthread.php?s=&postid=15477075#post15477075 target=_blank>Originally posted</a> by evsalty
So you would be feeding a pump for your closed loop off your sump return pump? IMO that wouldn't be a good idea. You would have to match the CL pump to how much water is being fed to it or you risk cavitation or having it pull too much of the return water.

If not that and just a closed loop with the pump above the tank you would need to either use a special self priming pump or would need something to keep the power off after power outages until you personally can reprime it and restart it.

^^ u could always put a check valve before the pump inlet so water doesnt drain out of the inlet

 

[evsalty]

True but check valves fail very easily. It only takes one tiny particle or a little build up to cause a leaky CV.

Also check valves will be a restriction in the intake plumbing and that is very bad for a pump.

 

[DarG]

Place the CL pump below the tank and the intake low enough in the water that water changes dont lower the water level below the outlet. You can also plumb a T with a cap on the intake so that you can prime the pump through the T if needed. Just need to make sure you have a good seal for the priming port. Threaded cap and teflon tape works. I ran a closed loop like this for years on an old system.

 

[evsalty]

OP - since intakes in the tank are your concern your best option is probably to make another overflowand use it for a closed loop or to house a pump. This would allow you to build it to flow how much ever water you want up to a point. Or like I said before calculate how much water your current overflow can pull from the tank, subtract how much your drain is taking from that and then you will know how big of a pump you can place in the current overflow without effecting the water height in the overflow.