Closed Loop Question

pballafreak · 12-04-2005, 05:41 PM

I am soon going to make closed loop system for my 10 gallon nano, drain on one side of tank, return on the other, i know that I can plumb my return to it just goes right over the side of the tank, but can I do this for the drain. Im sure drilling the tank for an overflow for the drain would work better. But im not ready to drill tanks yet as this tanks glass is so thin. So I was wondering if I could do this for drain, and if so, should i use just a open hole or a peice of pvc with holes drilled in it for the drain.
Thanks in advance
~mark~

motorslave · 12-04-2005, 05:54 PM

An over the top set up would work fine. I had to such closed loops on a 55g. The key IMO, is to make the intake a bigger diameter then neck down at the pump. This way you have tha added wait of extra water feeding the pump so it doesnt have to work to get its water. Making a ppump work for its water isnt good fopr the pump. On the intake you could use a piece of PVC with many holes drilled in it for sure, it would be best to get a sstrainer to fit, you want to draw of water spread over some space so its not to strong of a suction so no critters get stuck to it (been there) You can do a very simple set up for it!

Robert

pballafreak · 12-04-2005, 05:57 PM

Thanks for the quick reply, that helped me alot. I am almost finished with the stand for my tank, so the next step is the closed loop and the hood. One other question, are there any precautions I need to take for If the power goes out? Or when i make the T at the top to get the system ready do i drill a hole that will break a syphon. Once again thanks
~mark~

motorslave · 12-04-2005, 06:01 PM

For a closed loopp there is no worry of back siphoning when power goes out. Basically the just stops and stays put. If you have a sump then you have to worry about back siphoning. To remedy this you can drill a hole in the sumnp[ return just blow the surface of the water in the tank, make sure you test the sump to see that it will hold the volume that will flow back (there will be some) and make sure you check the anti siphon hole as part of your regular maintainence, they can plug.

Robert

Doug1 · 12-04-2005, 06:51 PM

OK, since I havent played with over the top in/out closed loop, hopefully someone will clarify the initial siphoning when starting the pump and firing up the closed loop. How do you maintain the loop if the power goes out.
With a typical closed loop, the intake and outflow are both submerged and the plumbing throughout stays continualy flooded.
With a typical overflow, when the power goes off and the pump stops, the water can only drain to the bottom of the overflow teeth, assuming that the return line is near the surface or has a siphon break hole drilled near the water line breaking siphon. Once power is restored, the pump sends water from the sump back into the tank and the rising level spills over the overflow and down to the sump.

If i remember correctly from Roberts original over the top CL there was a cap to facilitate priming the pump and getting the loop going, what happens if the pump stops?

reef_noob · 12-04-2005, 07:28 PM

Quote:

Originally Posted by Doug1

If i remember correctly from Roberts original over the top CL there was a cap to facilitate priming the pump and getting the loop going, what happens if the pump stops?

Bingo.

The trick is, the cap is on the intake side, above the water level.
To get the whole thing running, you fill the intake line from the cap and then put the cap back on.

If the pump stops, there's always enough water in the intake line to keep it primed as long as you don't open the cap again.

reef_noob · 12-04-2005, 07:33 PM

This is an excellent closed loop with scwd that demonstrates how to run one over the top. This came from http://www.melevsreef.com/closed_loop/, which for some reason crashes my browser.

motorslave · 12-05-2005, 02:06 AM

Ahhhhh, good catch Doug, how soon I forget! The cap doesnt realy seel all that well, what I wound up doing was using a "T" at the top with a ball valve to get a good seal and keep the air out. The "T" would be set side ways.
As far as the pump stopping and losing prime in the loop, I had a bad pump at first that would stop pumping. I would have to unplug it and plug it back in, sometimes several times, and I never lost prime once the loop was primed at initial start up. Water stays in the plumbing at least to the water level in the tank and once the pump gets going again the water in the pipes is enough to get the suction going again. I dont remeber if the water even drained at all but I dont think so, I think the whole loop stayed full as the intake and return would balance each other out. Of course my mind isnt what it used to be, and of course thats not to say it was ever much!!!!
I do know that I didnt have to re prime if power was off.

Robert