Any Tips On Small Sumps?

Ok, so the long-running saga of me setting up a 400-litre Rena tank has finally reached the stage where I'm putting a sump in the right-hand cupboard of the stand. Space is a bit tight in there, so I want to use all of it rather than fit the largest commercially available tank (like a Clearseal) in.

To be more specific, the sump can be 38cm square on the base and around 50cm tall I think (need to check again how much room I need to leave to be able to get the skimmer cup off) - and will be fed by a Tunze overflow [sorry drilling fans, I just don't have the guts to drill the tank!] [though I am going to have to mod the lid and rim slightly]. Said overflow apparently allows the tank water level to drop 2cm when e.g. power failure causes the return pump to stop - at 150cm long by 50cm deep (as in front to back, not water depth) I reckon that equates to 14.2 litres of water from the tank plus whatever's in the overflow unit and pipe - so worst case estimate 20 litres of water heading downwards [which conveniently fits with Tunze's own version (at several hundred £'s all in) that has a "safety volume" of 21 litres I think], causing a 14cm rise in the level in my sump if I use 10mm glass - which sounds a lot to me... Anyway, all told I think I'm ok on the whole flooding issue

What I'm planning to put in the sump is a skimmer (already got a Tunze 9010 for the purpose), a heater (one will remain in tank - it came with 2 and I'm keeping them both to have redundancy), the return pump of course, plus a small pump supplying water slowly to a phosphate reactor sitting in the other side cupboard. Also in said cupboard will be a 25-litre storage can of RO water to supply a Tunze top-up gizmo sitting in the sump. Finally, I was wondering about putting in a denitrator at some point if I can't get the nitrate to hold at a low enough level - but am a bit worried about the space it would take up.

Anyhoo, today's questions (for those not bored to sleep by the above) are:

1) What should I do about the design of the inside of the sump? What I've come up with is a tall vertical wall from the middle of the back wall to the centre of the tank, so that looking down from above it has a U shape - with water coming in at one end and back out at the other side of the U so that it has a chance of getting skimmed and dephosphated. And a second idea was to supplement that with a shorter wall across the middle left to right - so that water has to flow over both of these and spends longer going past the skimmer etc. Then I was wondering if I need the first interior wall to extend to the front of the tank but have a gap at the bottom so that water truly has a really well-defined path past the various intakes. Is this all over-complicating things? Will it reduce the flow rate and cause flooding?

2) Should I have a partial or full-sized (removable) lid to reduce evaporation? I was thinking of a permanent lid from the back to about 1/3 of the way to the front, with appropriate holes for the drain and return pipes, then a removable one to keep water loss down over the rest, but allow access to the skimmer cup.

3) What about materials? I'm thinking this is worth having a pro build me a decent glass sump rather than bodge one myself, though I like the sound of making one out of perspex as I can confidently cut and drill it!!! I was also thinking first thing I'd do is make one out of cheap plywood or something to check everything fits together ok - not to actually use - am I just being over-cautious?

Thanks in advance everyone! And sorry for the lengthy (as ever) post!

Paul

My sump must be the smallest on here.
http/www.fishforums.net/content-page/202...ation/page/280/
Yours is a bit tight though but I would still go with the baffle method.
Indulge in this site for some more ideas
http/www.melevsreef.com/allmysumps.html
Regards
BigC

i just read all of that thread on your tank BIgC. love it. I dont suppose you have a plan of that sump showing the compartments and how they are split do you?

Hi,
The sump itself is only small 280x280x460mm, (not much room for getting yer hands in) Basically its an all glass affair I made myself. Not wanting to smear silicone all over the place when installing a baffle I purchased some plastic "U"channel ( 3/4") and siliconed that in the middle front and back panes. Next I cut 2 pieces of glass (same size) and siliconed these to the "U" first chamber to the tank floor, (run a bead of silicone on the bottom edge of this plate before installing) Second chamber side leave a 25mm gap at the bottom. So you should now have one piece of glass siliconed to the tank base (chamber 1 side) and another 25mm higher but with a 25mm gap at the bottom (chamber 2 side) Thats the baffle in situ.
When you run the return from the tank you are going to get lots of bubbles, If I had left the sump as it were with just the above solitary baffle, this would have not been enough to stop those bubbles entering my tank, so I had to come up with something (and small) My solution was to build (again out of glass) an "L" shaped component (silicone this together first) One side nearest the baffle is higher than the other by around 40mm. (the box size was roughly 75mmx75mmx400mm). Again the glass was flush at the bottom and a bead of silicone was run around all edges inc. the bottom that was goung to adhere to any glass surface. This was stuck in the back corner of the sump where my return came in. I made a little cradle (from eggcrate) to sit at the bottom of this pre sump compartment to allow free flow of return water before hitting the media, For the media I opted for bio-balls but I could have used ceramic rings (to break up the water bubbles) on top of this I placed a course Jewel filter pad (made to measure and kept the bio balls in place) then a sock of Rowaphos and then topped off with some filter foam to stop fines of Rowaphos from making a mess of the sump floor. I was going to originally have the Eheim return pump in chamber 2, but seeing as they can run in or out of water I now use a syphon method and have the pump outside (bought myself some more room). The sump is lit by a daylight spectrum 18w energysaver twist bulb. My Nano Skimmer is in compartment 1 and my heater/stat and pump return is in compartment 2. I think thats about it really. If there's anything thats not clear about the above then just ask some more questions.
Regards
BigC

what did you use for the overlow? is the drilled hole plugged and sealed with like a water tank valve and push-fit pipe?
cheers

what did you use for the overlow? is the drilled hole plugged and sealed with like a water tank valve and push-fit pipe?

Click to expand...

Read my thread in Nano section to see how to do it,
Regards
BigC

BigC said:

Hi,
The sump itself is only small 280x280x460mm, (not much room for getting yer hands in) Basically its an all glass affair I made myself.

... snip ...

If there's anything thats not clear about the above then just ask some more questions.
Regards
BigC

Click to expand...

Ok, well mine will be a little bigger - I have 380x380mm footprint to play with, given the Rena cabinet. Thinking about making the sump myself as I'm pretty handy on the DIY front, though having never worked with glass or acrylic (anyone any thoughts on material choice?) and not wanting a living room floor covered in 400+ litres of finest fake sea water, maybe I'll get a pro to rig this up... I have a little more height to play with as well, with 690mm clearance in the cabinet, but needing 90mm clearance to get the skimmer cup off and say 10mm for a foam base for it to stand on that comes down to 590mm - and I'm thinking maybe I'll need an extra 10cm for fiddling with the pump, piping etc. so actually maybe about 500mm tall is all I've got. Am planning to build me a dummy version in either plywood or cardboard (got loads of boxes up in the loft from when we last moved house!) to see if I can actually get in and work in the sump...

I'm planning on having a full-height internal diving wall running from the back to the centre of the tank to make the whole thing a U shape, which with a bit more fiddling gives me 3 chambers so far:

Chamber 1: Water entry - the above dividing wall creates an entry chamber, currently planned at 180mm wide mostly because that means I can use a single piece of glass/acrylic running all the way front to back to add a bit of stiffness / reinforcement - though it won't be full height in the front half of the sump, but more of that shortly...

Chamber 2: Skimmer - this chamber is basically big enough to sit my Tunze 9010 in "Cabinet" mode with its foam-covered exit pipe in place, with a bit of spare room for a heater/thermostat (wondering if I can actually put both in the sump? Maybe I don't even need both?) and a tiny little pump that's going to supply a pair of phosphate reactors connected in series in the other side cabinet, one containing a phosphate absorber and the other carbon. Gonna try running with and without the latter once all is working, not really sure whether I should use it or not. Anyway, chamber 2 exits through a baffle system with 1" (25mm) spaced verticals - just checking, the water goes over the first, under the second, over the third plate right? How tall do the "flow-over-the-top" baffles need to be? 15-20cm would be a good operating depth for the skimmer so I figure they should be that tall, right?

Chamber 3: Return - am not planning anything else in here at the mo, it's kind of a safety volume, in that if I run it at e.g. 10cm depth to ensure the pump is covered, I'd have about 24 litres expansion volume on the left side alone - enough to allow the 2cm drop in tank depth (~15 litres in mine) that a pump failure would produce according to Tunze (the makers of the overflow I'm using).

I'm going to see if I can attach my sketch...

Thoughts and comments essential!!!

Thanks in advance,

Paul

Just pinning a couple of PMs in here so I can keep the thread going...

From Big C:

> Hi,
> For future diagrams could you please tell me what software you used for your sketch of your sump ...surely not MS paint
> Regards
> BigC

I actually used PowerPoint, working at 30% scale from real object size - so e.g. the 6mm (0.6cm) thick panels were 0.18cm wide shapes in .ppt file. I then screen-grabbed in slide show mode, pasted into, yes, MS Paint - cropped and saved as a gif to get the file size down! Wish I had a decent graphics package, would make this kind of thing much easier!

From StAndy197023:

> Hi,
> I have similar problem having a Rena tank. Have you by any chance got any pictures of your sump.
> My LFS said about removing the two supports and having a steel frame constructed but I dont really fancy the disruption
> this might cause.
> Regards
> Andy

Hmmm, sounds familiar - a guy in my local (to work) branch of the really big chain of fish shops that advertise on the back of Practical Fishkeeping said he'd done the same with his big brother version of my tank, the 2-metre long one. Can't say I fancy that, not sure what I'd cover the resulting open area with - and if was going to spend what I'm guessing is quite a lot of cash to achieve this then I'd just buy a dedicated tank with built-in overflows etc.! Which I'm kind of wishing I had done, but too late now...

Anyway, I just finished building the cardboard version of the sump from a big old box I had up in the loft. Once I get the photos off my wife I'll upload them - should give you some idea of what I'm putting together. The good news is everything fits very nicely so I'm just going to wait and see if anyone comes up with advice on whether I should adjust any of the sizes. Then it's tank-builder hunting - anyone know someone in the London area who'll have a crack at a slightly tricky sump?

pmb_67 said:

From StAndy197023:

> Hi,
> I have similar problem having a Rena tank. Have you by any chance got any pictures of your sump.
> Regards
> Andy

Click to expand...

Ok, here goes - this is the sump in cardboard format! The big corrugated hose is the input to the sump from the tank outlet, the straight pipe on the left won't be that tall as it'll need to bend a few times to get out of the sump and along the back of the tank to come in at the far end from the overflow. The middle divider isn't quite right in this picture, plus I think if I go acrylic I may have a thin rim all round like on all the http/www.melevsreef.com/ sumps!

The little pump (labelled "P+C" in my earlier diagram) I've currently sat with the skimmer, but I guess it could go in the "return" chamber. Am planning at the moment to have the P+C treated water come back to the sump to avoid too many pipes in the main tank, plus that wee pump would struggle with the 1.5 metre head I guess

One thing I hit on when I went back to my cabinet with the cardboard sump - firstly I'm going to have to move my multiplug bar thing to the outside of the cabinet (no biggy, though I'd prefer it hidden), more worryingly I've completely forgotten to allow for my Vecton. It's currently inline in the return from the external filter in the cabinet I'm going to use for the sump - any ideas/suggestions?

Paul

Sure does look the part man. Good idea on the cardboard mockup, I should use that more often myself

SkiFletch said:

Sure does look the part man. Good idea on the cardboard mockup, I should use that more often myself

Click to expand...

Thanks Fletch! Hoping this sort of thing saves me a few wasted bad designs Am wondering now if I can extend it to the layout of the full tank - i.e. building a box the same size as my tank, but with the front removed - and dumping some big polystyrene blocks in to simulate the LR positioning... I reckon practicing the layout without the constraints of all that glass could be a good move - might even try this with the real LR when I get it, though I guess I'll be wanting to get in underwater pretty quickly too, huh?

Back to sump designs, I've actually come up with a new one. Was wondering if I should make more use of my "return" chamber - like, adding in either a denitrator in a box (Aqua Medic one, maybe) or going the more eco-route and putting a wee bush of macroalgae in there, kind of like Big C has in his... How big an algae bed would I need for any kind of impact on nitrate and for it to be sufficiently stable in itself? What sort of light would I need? Would an Arcadia Arc Pod provide enough? A quick search online rates them at 9W for a 21cm long unit - seems a bit on the low side - DIY time again? Anyway, this is the sort of layout I'd be looking at (see pic).

Any more comments etc. more than useful!

Paul

I'd be concerned that the final section with the return pump would be too small. Remember, evaporation only manifests itself in the final compartment with the return pump when a sump is used. So if that last compartment is too small, evap will drain it faster than you can refill it. You'd NEED an auto topoff to do it that way...

SkiFletch said:

I'd be concerned that the final section with the return pump would be too small. Remember, evaporation only manifests itself in the final compartment with the return pump when a sump is used. So if that last compartment is too small, evap will drain it faster than you can refill it. You'd NEED an auto topoff to do it that way...

Click to expand...

Yep, got that covered - got me a Tunze Osmolator already, does a very nice job of keeping the tank topped up from a 25 litre plastic jerry can of RO water. Not that I've got shares in Tunze or anything, but I would recommend this to anyone running any kind of tank with a bit of room somewhere nearby - it annoys me every day my freshie tank seems to have lost another millimetre of depth, there's just no room for any kind of top-up nearby though.

Paul

Well in that case, go for it