Water Height

[JaminRat]

Hi folks,

As many may be aware I am in the midst of a tank upgrade and building my own weir. The question I need answered is... is it possible to calculate the height increase of the water in the display when the return pump is running as opposed to when it is off.

Failing that is there a set amount of space to leave. The tank is 18" high ( footprint 48"x15") with bracing bars at approx 17" from the base. There is 10" of linear overflow, 3/4" bulkhead (in the base of the tank) and my return is rated at 338GPH at 5.36' of head which is what the calculator over on RC came up with. RC calculator recommends 0.76" bulkhead with 6" linear overflow so may have to tweak the pump down slightly.

I was thinking of having the overflow set at 16" from the base of the tank with the comb filling the 1" between the top of the overflow and the bracing bars?

Hope someone can help.

Thanks
Ben

 

[Wave Ace]

1. are you having a hood if so you want the water lever just above the bottom of it so you cant see the water live
2. And if you use an adjustable comb, weir then set this below the attended water level to allow for final ajustment

 

[JaminRat]

Waveace in response to your questions.

1. The tank will have a hood but I'll build after I have set the waterline for just that reason. I want to keep as much depth as possible but still allow enough room in the tank for the content of the return chamber should the overflow ever get blocked. You can garantee that if it's going to happen it'll either be in the middle of the night or while your away. Sods law in full effect lol

2. Not heard or seen adjustable height weirs a link would be good if you've got one or some more info. I was going to get the glass cut to make the weir so will be a fixed height and then front it with blue acrylic. The comb will then be cut into the acrylic. Hope that makes sense.

 

[SkiFletch]

Actually you shouldnt have to tweak the pump down at all. Having a wider overflow will allow the tank to drain faster and keep the visible display level just a little lower. planning for a 1" rise in water in the display is a great idea, and it sounds like you're really on-track here. what pump are you gonna use just out of curiosity?

 

[JaminRat]

Actually you shouldnt have to tweak the pump down at all. Having a wider overflow will allow the tank to drain faster and keep the visible display level just a little lower. planning for a 1" rise in water in the display is a great idea, and it sounds like you're really on-track here. what pump are you gonna use just out of curiosity?

Thanks Ski, I'm using an eheim 1250 for the return but I've scrapped the spraybar idea I was originally thinking of. There seem to be calculators around for everything just wondered if there was one for this. Definitely on track but if I flood the place again the better half will most likely loose her calm demure. So it's time for a little science theory insted of practical. LOL

I'll keep the return section as small as possible roughly 2.5 usg and even if the normal water height with pump running is right on the bracing bars there is still 3usg of space in the tank before my socks get wet.

 

[JaminRat]

Bit the bullet and bought the glass for the overflow today. Went for 16" tall in the end and will add the comb to fill the inch beween the top of the overflow and the bracing. Fingers crossed it's enough. I'll start construction tonight.

Anyone got any hints on the best way to approach this?

 

[SkiFletch]

Yeah, patience . Also conveneint plumbing can make your job LOADS easier. Make sure you use ample valves and union fittings to allow you to tweak things that dont work. Also, just in case your pump proves to be too strong, equip the pump outlet with a T fitting and valves on all 3 sides. That way you can remove a pump if necessary, and shunt water either back to the sump, or up to the display tank. Gives you some fine control over the operation. And remember, always have your hand on the plug/kill switch for the pump and be prepared for siphons just in case

 

[JaminRat]

Yeah, patience . Also conveneint plumbing can make your job LOADS easier. Make sure you use ample valves and union fittings to allow you to tweak things that dont work. Also, just in case your pump proves to be too strong, equip the pump outlet with a T fitting and valves on all 3 sides. That way you can remove a pump if necessary, and shunt water either back to the sump, or up to the display tank. Gives you some fine control over the operation. And remember, always have your hand on the plug/kill switch for the pump and be prepared for siphons just in case

Nice one ski but the plumbing is all sorted I meant a little advice on assembling the overflow and fixing in place but don't worry I've made a good start.