Water Physics Question...

[tamz273]

Hey guys, I have a question for you experts!
I have a sump running with an overflow box.. The overflow is almost full, and the sump water level is below what I would like it to be...

If I add water to the sump, it goes up to the tank and the water level in the sump increases proportionally with the tank level...

What should I do in order to raise the sump water level without changing the tank water level? I was thinking of putting a valve on the return pump's output, so that I can close it off a little bit... But wont that cause the water level in the tank to CONSTANTLY drop? and eventually overflow the sump...?

[Amphiprion]

Once the effluent from the return pump and the siphoning action from the overflow balance, simply adding a bit more water to the sump should raise its water level. There is a proportional work load that decreases with a higher water level, but not enough that it would negate that.

[tamz273]

That's what I was thinking too, but whenever I add water to the sump, it seems to simply pump into the tank and cause the tanks water level to rise...

Im using a cpr overflow, and that seems to be constantly full, unlike its "meant" to be working... Its supposed to look like a waterfall, instead the water level reaches the level of the rim and it just looks like a full container of water (but it is still overflowing water to the sump)...

What should I do?

[sundevil_brian]

you've reached equilibrium between your pump and overflow, so the distance from the top of the water in your sump to the top of the water in the tank will remain constant no matter the height of water in the sump. so if the sump water height raises 1" the tank water height raises 1" so the distance between will be the same as before. (you already figured that out)
To alleviate this problem you need to restrict your pump or add another overflow. the cheaper of the two options is restricting the pump. simply place a ball valve after the pump (never before it!) and restrict it till you get the waterfall effect you mentioned in your overflow.

[tamz273]

oh alright... funny thing is, it was running perfectly fine before a water change i did... right after the water change, this problem decided to happen!! Any way around it or is this the only solution? (Ball Valve)

[snailrider]

Something sounds wrong, with your setup or something. If your tank has not overflowed onto the floor, your siphon is working. Restricting the pump output is not the way.

On the outside of the tank, you may have to lower that resevior to lower the main tank level.

Please supply a few pictures of our overflow setup


Or you may just need a larger diameter u pipe

[snailrider]

oh alright... funny thing is, it was running perfectly fine before a water change i did... right after the water change, this problem decided to happen!! Any way around it or is this the only solution? (Ball Valve)

Then you got an air bubble in the siphon tube

[tamz273]

so i should suck it out and close the siphone again? ill try that right away actually... will post in 3 minz...

[tamz273]

just restarted the siphone (let air fill it up till it stopped and then sucked the air back out) and its sitll the same problem... the overflow box is filling up almost to the rim...

[tamz273]

actually its settling back down... not sure if theres an air leak or if its working properly.. its constantly going down at a VERY slow rate... it may have stopped now... should i try topping off the sump? or will this cause the tank water level to rise too?

[tamz273]

Alright, sorry for posting so many times in such a short time, BUT you where right, there was a bubble and now its out and im back to normal flow in the overflow box...

Should I technically be able to top off the sump now without having the tank water level rise? Or will it still rise if I add water to the sump...?

[sundevil_brian]

do you have a ball valve on your drain? sometimes when my diy overflow slows down i close the drain but leave the return pump on then open the drain, this causes a "flush" (for lack of a better term) water rushes down the drain and loosens any debris or air bubbles that have been trapped, if that doesn't work I check if there are air bubbles in my U-tube. those are the two things that usualy fix my slow overflow.

also how is your drain situated in the sump? i.e. is the output underwater? if so this will cause a back pressure slowing the drain down, raising it above the water line will help or by using a T at the end, one end of the T underwater and the other above for a vent.

[sundevil_brian]

now that the bubbles out you should be able to add more water to the sump w/o raising the level of the tank now

[sundevil_brian]

just one more thing, with u-tube overflows you want to check for bubbles in the u-tube at least every other day. I've had problems with bubbles and almost overflowed my tank several times, finally got a aqualifter pump for the u-tube and that "solved" my problem (still need to do occasional maintenance but def not every couple of days)

[tamz273]

alright i will give it a shot... my drain hose is underwater in the sump, its also got a U-Like figure to prevent it from "gurgling" or in other terms sending air bubbles back up the over flow and making noise...

[Amphiprion]

Look into an aqualifter pump to keep bubbles out, btw.

Nevermind. Beat me to the punch.

[snailrider]

Alright, sorry for posting so many times in such a short time, BUT you where right, there was a bubble and now its out and im back to normal flow in the overflow box...

Should I technically be able to top off the sump now without having the tank water level rise? Or will it still rise if I add water to the sump...?

Give it a shot, be at ready to unplug if need be

When I had my first siphon overflow, I pumped about 3 gallons onto the floor when the bubble kept growing. Seems the little bubble accumulate and eventually made a big bubble that broke the siphon.

Well I strongly advise clear U tubes for these overflows, or a small nipple on the top with a hose running to a power head.

You should be fine for the time being. Consider a shutoff switch in the sump also

[tamz273]

o alright.. ill look into that if this problem keeps happening...
i just want everything to run stable enough to go on vacation... and not have to worry about overflowing or anything else... just simply tell my roomate to feed the live stock and not worry about any of the other stuff going wrong... im about to top off the sump, will let you know how it goes in a few minutes!

[tamz273]

i already have a shutoff switch in the sump... only problem is it keeps varying levels so its not really active atm.. another thing is instead of the aqualifter pump, can i simply run a hose form the nipple to any of the powerheads in the tank and it will work fine instead of a aqualifter?

[snailrider]

i already have a shutoff switch in the sump... only problem is it keeps varying levels so its not really active atm.. another thing is instead of the aqualifter pump, can i simply run a hose form the nipple to any of the powerheads in the tank and it will work fine instead of a aqualifter?

It might if the power head is strong enough flow to create a good suction

[tamz273]

yeh thats wat i was wondering about too... i got it all back up n running, MANY THANKS TO SNAILRIDER AMPHIPRION and SUNDEVIL BRIAN!!

im probably going to go out and buy a really strong power head tomorrow, and hopefully it will do the trick... the sump is at the desired level now though! and the float switch is in place incase worse come worse!

thanks again guys! couldnt have dont it without u!

[tamz273]

Alright guys! The problem is back!
This time I just left the tank running, I came back home today to find out that the sump water level has dropped again, and im back to the same problem... Only this time, the water level didnt drop as much as yesterday...

I checked the overflow box, no air bubbles... I tried to top off the sump a little bit through siphoning some water out of the tank and into the sump... it rose for about a minute and started comming back down...

Solutions?

[tamz273]

Anyone...?

[snailrider]

still sounds like an overflow issue, some pics might help. If you do not have a clear/seethrough overflow, my guess is still bubbles or some restriction.


When it worked proper how long did it function correctly, days, weeks, hours etc.

[tamz273]

it functioned properly probably for a few hours? I went to bed and woke up the next morning to find out it has dropped again...
I sucked out all the air from my overflow siphon today, and even took in some extra salt water just to make sure there was nothing left in there... then i connected the siphon to a powerhead in the tank...

here are 2 pics of teh overflow...

[snailrider]

Very interesting indeed. I wasn't expecting that. Is that white pipe clogged or just undersized? The water level in the chamber with the black strainer, should not be that full. Something is restricting that down pipe or you are just pumping way too much water for the down pipe. What gallon per hour (gph) rating is the pump in the sump, LOL?

You may need a larger diameter drain, or a diverter for pump side if your not clogged. OR-if your tank is not tempered, drill it.

So on the piping going down to the sump from the overflow box, are there a bunch of turns, and is there always a "fall" in all sections of the pipe?

I'm running two 1 1/4 inch pipes as overflows, and yours looks like one 1 inch or less. If you are pumping 3-400 gph, that will never keep up. Or if it does only till it gets partially clogged.

So looks like a nice setup and fantastic view. Hope your fish don't get vertigo :)