50 l sump design

I have a 50l with a cracked bottom that I would like to convert to a sump for my 250l tank.
Cutting the old bottom out was allot tougher than I expected, but thick fishing gut seemed to do the trick in the end.
I replaced the bottom with 6mm glass, just to be on the safe side.
Here is my sump design.


I've placed the heater under the perforated perspex plate, to save space. Is this a bad idea? I haven't seen this anywhere else, so please comment on that if you don't mind.
My inlet compartment is allot smaller than most designs, but it gives me a larger filter aria. does it seem ok to you guys?
I'm going to use my HL-BT700 power head as a pump in here.
How do I work out the diameter of my siphon to keep up with this pump?
I suspect the siphon needs to be slightly faster than the pump to avoid a dry pump.
Is this just a trail and error thing, or are there ways to work it out?
To start with I'm going to use sponge at the top, and gravel for the rest. This should be ok right?
I'm thinking of taking the filter media out of the power-head, and replacing it with fine floss, just as a final polish before the water goes back to the tank.

 

Maintenance in these so called "big bore" design sumps will be as close to impossible as make no difference...

 

Also, water will follow the path of least resistance, so why would it go up through the filter media and down again ? I think it will just flow straight underneath and back out again

 

Sometimes it is best to keep it simple and as straight forward with tried and tested designs, especially if it is your first sump

 

ok maybe my drawings were unclear. the 45 degree inlet chamber is sealed at the bottom. Its only there to get the water to settle before overflowing onto my filter media.

 

Ust think, if you stack all your filter media on top of each other and you want to clean something at the bottom you will need to remove everything in the sump, this is not a very practical design in general, and I, having had more than one or two ranks with sumps would never recommend this to anyone. Also, flow rate through the filter is controlled by the return pump and how many litres an hourit can pump.

 

I hear you on the single compartment cleaning problem, but after reading prof Dirk's posts on flow rates and sump designs, this seemed like the way to go.
Regarding cleaning: I thought I would put my filter media in lots of small net bags (like the ones you buy oranges in) to help with the cleaning. the bottom perspex stand will also be removable.
I was under the impression that the top layers of sponge and floss will be the things you clean regularly, and the rest of the sump will only need cleaning once a month or less??
Thanks for your feedback, and please keep it coming

 

I cleaned out my garage today and found a 60l plastic bin on small plastic wheels.
This seems like a much stronger sump container when it comes to moving and cleaning it.
Any reason why people don't use these "Rubbermaid" sumps more often?

 

My sump was and is (on the new tank) the same concept as this - worked very well for me (350l tank and 75 l Sump)

I used Bio balls and ceramic rings (proper ceramic rings are expensive hence some bio balls too ) have never used gravel but i think the Prof does
my heater was in the "inlet chamber" as my heat fluctuated a bit so needed to be able to change it and was afraid the sump would run dry one day and my heater would pop, the first chamber will never run dry

Replaced/cleaned my filter sponge every second week - never really removed my filter media (balls and rings) unless something went really really wrong - if the sponge is doing its job properly you shouldn't have crap lower down. not sure if people would see this as poor husbandry but as you say trial and error - what works for me might not work for others

That pump is rated 690L/H - should be ok... i think ... , just remember you loose flow the higher you pump up and i don't know how that pump will handle the strain of pushing water up as it wasn't designed for that (just thinking aloud there)

Just my 2c

good luck and put some pics up as you go along

 

Tried to stick perspex to this plastic bin yesterday, but the pvc cement didn't stick to the bin. Silicon doesn't really stick to the pvc or the bin. Anything else i could try that is fish safe?

 

Update on my sump
I finally stuck everything together with pratley putty original.
here is the proof

 

update on this:
The sump worked fine untill i picked it up to clean it outside. One of my perspex walls came loose.
There is a good reason why most people use glass.
So This failed. Don't try this one folks, at least not the way I did it!!

 

Damn Varkie - all that work and now this - sorry to hear. So now what are you planning ?

 

I recently bought a 600L tank with an overflow system and a sump underneath. I have other tanks with built in filters etc. and I am SO happy that this new tank does not rely on the syphon system. This syphon business it seems is so difficult to calculate the correct flow rates. The overflow system that I now have is practically faultless and I reckon is the way to go for ease of use!!.
Not that this info helps you @Varkie but just wanted to share my new found 'happiness' with other members thinking of using the overflow system. I would never normally have thought of buying a tank with this type of system - now I would LOVE to convert ALL my tanks to the overflow system and sump!!!

 

Hey @eros111 I'm glad you like the overflow system. As a DIY project, the siphon overflow is easier and non destructive to your tank. The flow rate isn't that hard to calculate. You basically only need a siphon overflow that can handle more than your pump.
I think this is the main reason why people go for it rather than drilling the tank.

 

also its a lot cheaper....

 

Ah no man, I was hoping this could work. Have you tried gluing it with a hot glue gun ?
Some more info on acrylic gluing. cutting and joining perspex - SA Reefkeeping.com

 

@Good_Times: I've read online that hot glue gun glue is not aqua safe. It also didn't stick to my plastic bin. The only way this could work is if I made brackets to screw the perspex to the plastic bin, and then glue it with the pratley stuff afterwards.
This might just make the whole thing leak. I suppose I have nothing to loose.
I think in the end, the bin is the problem, not the perspex

 

suggest that you just go and buy a glass tank and convert it into a sump....

 

Yes I agree with oupoot!!!

1 foot tanks are cheap.