i always have used a comb to stop bits of food going down into the overflow.

but realisig that combs are expensive, i may not do it this time.

i am looking at a rectangular shaped overflow so it has slightly more surface to drain than a triangular straight line.

any ideas on how to make it so food wont go over.

my thoughts

1) just do it with no comb but another bit of glass restricting it so fish dont go over. maybe 1cm straight gap?

2) mesh, like a plastic garden type mesh

or i was thinking just making sure that i feed just enough so food doesnt get over the overflow.

OR maybe using more sinking cichlid foods and limited floating foods.

Plastic mesh should work. Something like gutter guard might even be the right size and shape even. I'm not sure how exactly you'd fix it in place. Heavy use of silicone probably would be the first thing to try.

Go with plastic mesh siliconed in place. Here's the thread about pipe sizes I was talking about earlier, a 25mm drain should only flow 600gph, probably want more than that for your big tank. Also look at the friction head loss figures, 1" plumbing for the return will add twice as much friction head as 2" plumbing.

http://www.monsterfishkeepers.com/forum ... Flow-Rates

a 25mm drain should only flow 600gph, probably want more than that for your big tank.

David the marine tank you sold me has 25mm drain and can under full syphon drain much more than my 5000L/hr pump can deliver (around 4000L/hr at 1m height).

So I reckon a straight piece of 25mm pipe of 1m length can drain up to 6000L/hr (1500gph?)

Agree 25mm is too small for the tank Henward is planning. I would go 32mm. Hansen all the way baby full on BeanAnimal style yeah! :thup:

Henward this is the overflow I will do on my 800L with 25mm Hansen fittings, 2 holes out, 1 in. Standard overflow comb

David the marine tank you sold me has 25mm drain and can under full syphon drain much more than my 5000L/hr pump can deliver (around 4000L/hr at 1m height).

Have you measured the flow of the pump, or relying on the manufacturers graph? TBH those figures on MFK did seem a little low, but I'm not going to try re-check his math. I'm going 2x 50mm on mine (2000L), one running full siphon (with a ball valve to adjust it) and the other taking the excess. Having redundancy is a good thing when it comes to overflow drains...

My return pump will be same as my 1200 litres.

It served me well, i am increasing bio media efficiency so the return pump will be mainly for bio filtration.

the side of the filter, iw ill have a inbuilt filter box for mech filtration. that will have the big turnover relative to the tank size.

in the 1200, i had 25mm and usually was on fu ll siphon and the water level was never more than 10cm above the hole i found.

only issue is now, i am trying to find a way to avoid the water fall effect.

um er not my area but can I ask if you fill the overflow box with bio media...balls...porret foam...filter wool...will it not porvide a prefilter and eliminate the water fall effect?

nav

um er not my area but can I ask if you fill the overflow box with bio media...balls...porret foam...filter wool...will it not porvide a prefilter and eliminate the water fall effect?

nav

It could, i wouldnt do poret, has to be something that will not block.

danger is bio ball may block the hole on the overflow drain.

but i am considering something similar, just to break the speed of water and divert it a little.

Have you measured the flow of the pump, or relying on the manufacturers graph?

Yeah from the graph.. could be wrong but it sure seems like a lot of water :dnc1:

i am trying to find a way to avoid the water fall effect.

Easy! Just do an overflow like David described above or like the one I have shown.. super silent.. but you need two drains, one adjustable for full syphon, one for the rest (like david said)

Having seen Henwards old tank running, I think by "waterfall" he means the water cascading over the overflow (literally like a waterfall) rather than noisy drains. I think you just need to make sure the overflow is wide enough for the amount of water going over it, only other thing I can think of is to make the drains at the top so it doesn't have as far to fall.

Yes that is how your old marine tank is and what I based above design on. The whole end of the tank is an overflow and water runs into the box through the comb without making any noise and then down the two drains also without noise.

To me this is the best overflow possible. Super silent, easy to control and doesn't take up any precious floor space.