• Looking to buy a cephalopod? Check out Tomh's Cephs Forum, and this post in particular shares important info about our policies as it relates to responsible ceph-keeping.

Sump Question


Jul 20, 2004
I've seen some sumps online that use a normal tube to gravity feed water into their sump, and then use a pump to pump it back into the main tank.

Instead of buying a pump to force the water backup to the main tank, would it be ok to use a powerhead?

Or am I completely off track here?
Yeah, a powerhead would be fine... i used to use a Hagen 802 powerhead to pump water about 4 feet or so high :)
So all that nonsense told to my by the fish guys about drilling and tapping holes in my tank (and how much $$$ it would cost) was a load?

This makes things so much easier, I'll just buy a little 10 gallon tank and use that as a sump.

I do have one more question however:

Since the water running to the sump is going to be powered by gravity, if the powerhead was too powerful it would pump faster than water gets into the sump correct? How could I maintain a balance?

Appreciate all the help!
Unless you use a really large powerhead it won't be an issue. 1" overflows are rated for at least 600 gph. I have two 1" overflows and a 1000gph return pump and have no issues.
Okay, i misunderstood your question due to term use...

'gravity fed' means that there is normally a hole at water level or on the base with an upstand, and water freely flows through the hole by gravity into the sump through a pipe. This is what most people have and I would call a gravity fed / overflow sump system.

I think you are asking about a syphon fed sump, that normally sits on the back of the tank and works via a syphon from one tank to the other and is returned by a pump.

You are correct in thinking that to balance a lower sump with a syphon is tricky, in fact, its pretty much impossible as one wrong move floods your floor!

OR, if i was initially right, like Randy in his post, that you are just wondering about water leaving your tank via a hole at a slower rate than its being pumped up then yes that is also a situation to figure out.

My cuttle tank for example had 3 holes drilled at water level and returned by a 802 powerhead, that worked fine... 3 because i was making sure that if one hole got blocked the other two would be easily able to cope...

hope you can settle this :) have you seen a pic online to point to?
Originally I was asking about a syphon, whether or not it would work. I suppose that's a negative.

So, I do need to get a hole tapped just below the water line in my main tank and then place a 1" line/pipe going form the main tank to the sump. Then use a powerhead to return the water via another hole tapped just below the water line?

I assume I would just seal around the tubes with regular aquarium sealant?

Also, where do I get glass tapped for something like this?

Thanks again.
You can do it yourself if you have a bit. Do you have glass or acrylic? Acrylic is easy, use a portable drill and a hole cutting bit. Glass you need a diamond edged bit, or a dremel with a special glass cutting bit. Call a few local glass shops and pet stores and see if they can do it if you don't want to. I drilled two 3/4" holes in a 20 gallon glass and they came out fine, but I was nervous and the tank was only a $20 loss if I broke it.
Ah, I consider myself reasonably handy so I think I'll give it a shot.

The holes, how far below the water line should I place them on the main tank? And where should I place them in the sump?
sarcazmo said:
Ah, I consider myself reasonably handy so I think I'll give it a shot.

The holes, how far below the water line should I place them on the main tank? And where should I place them in the sump?

I drilled mine about 1 1/2" from the top of the tank, I think 1- 1 1/2" is about the norm. If you're using a powerhead just submerge it in your sump and no drilling is required. If you use an external pump you'll want the holes fairly close to the bottom. I'd drill them so the hole lines up perfectly with the pump suction. You'll also need to go out and buy some bulkheads.
Ok, so let me see if I fully understand before I begin.

Drill a 3/4" hole 1 1/2" from the top of my main tank. Then, drill another 1 1/2" from the top of the sump. I'm assumimg just get a couple 90* elbows and some pipe to connect them and seal with some aquarium sealant?

Then submerge the powerhead into the sump and have either a 3/4" hose or pipe connect it back to the main tank? I'm assuming I'd have to dirll another 3/4" hole for the return line as well?

So basically, three 3/4" holes, two in the main tank, one for the sump? All about 1 1/2" from the top?

I did some quick searching @ homedepot.com and this was all I could find in the way of glass bits.

I did find one 3/4 inch diamond tipped bit here but it's $41 dollars!

Did you just make the outline of a 3/4" circle and cut it out with a dremel? :?:

One last request, could you provide a link to some good bulkhead information?

Thanks again for all the help!
Found a great 'how-to' with pics on how to drill the glass located here.

I'll be picking up a dremel this friday along with some glass cutting bits to try it out on a 10 gallon. Suppose I should pick up some bulkheads first.
its a brave person that drills a tank FULL of water!!! LOL

make sure that you spray the drill bit and water ALL THE TIME, keep it really wet or thats when it will go wrong, A job I did last year, or was it two years???, involved me building and drilling about 800 tanks in a few weeks... never again!!!! LOL
How's this?

Well, I decided to go out and buy a dremel and try this.

Also, rather than purchasing some bulkheads, I just bought a few pieces of PVC. I figured as long as the water flowed down, I really didn't need a bulkhead.

Let me tell you, using a dremel and spraying water by yourself is tough! :bugout:

Here are some pictures. The first picture is from the outside, the 2nd from the inside. I suppose I should probably take out the o-ring.



I should of put the threads out but oh well. It's only a 10 gallon tank that cost me 10 dollars from petsmart. I'll make sure to not make that mistake on my main tank however.

I'm going to make sure it works tomorrow. If it does, I'm going to drill the hole in my main tank.

Please tell me I'm on the right track :jester:
If you can do it outside take a hose and tape it on the tank so that water can constantly flow onto the spot you're cutting.

Good luck and let us know how your homemade bulkheads work out.

Trending content

Shop Amazon

Shop Amazon
Shop Amazon; support TONMO!
Shop Amazon
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.