Cadgey's 700 litre


Reefing newb
Hi all,

I've been working on this project for a number of months now and after finally completing the canopy today it's in a presentable state!

I bought the tank second hand, it was a fish and (some) live rock system however most of the live rock had died (the tank was very poorly looked after and had very little water movement). Although there was a complete equipment system (i.e. skimmer, lighting, filtration) much of it was outdated and had to be scrapped. The previous owner used two external filter systems which weren't up to the job; I scrapped these and planned to build a custom sump. Anticipating a long and arduous restoration project I decided to dump the water, sand and live rock (keeping some of the rock "dry" to be used for building the tank it was complete) and to start from fresh once the building was finished.

So went about planning my sump; as the tank was manufactured for freshwater there was a split cabinet underneath- neither cabinet on its own was large enough to house a big enough sump. I had to build two miniature sumps and connect them with a central pipe that ran beneath the tank and through supporting beams. Obviously the issue with this is having a pipe large enough to accommodate the required flow rate in a large tank such as this – a large pipe means large bulkheads and other large (and expensive!) fittings.

As it was all a custom build I ordered the required acrylic online which was thankfully pre-cut prior to being sent! thus I stuck it all together - an extremely stressful job considering I was dealing with over £100 of acrylic and one poorly stuck seam would render the whole sump weak and prone to leaking. Thankfully everything was successful and there have been no leaks to date (touch wood!) With everything stuck together and drilled, I (after much fiddling, cursing, crying) managed to connect the two sumps together. With a tubes worth of reef safe silicone lining the inside everything was waterproof and I could progress!


As shown in the picture, the left hand sump houses the bioballs, micro bubble barrier, heaters and the refugium which houses macroalgae and (will) house the deep sand bed. The issue here was stopping the bioball equivalent floating into the refugium, however using some garden wiring we’ve been able to stop them floating into the refugium (they were floating into the right hand sump and clogging up the return pump).



The right hand sump houses the skimmer and the return pump. Theres nothing particularly exciting in here but the large valve you can see on the return pipe is used to adjust the flow of the return pump (the overflow box has a weaker flow rating than the return pump). Forgive the quality of the picture; what you can see is the reflection of the foil I use to stem the evaporation from the sump.


The last project (within a project!) was to build the hood which was becoming fairly desperate due to the massive amount of evaporation we were suffering from. We built it from MDF with reflective metal bolted on to obviously increase the light. In addition to this we built acrylic around the lights to stop condensation build up. The inside of the hood is shown here..


Currently I’m running 4x t8 lights along the tank, leaving one end free for LED lighting- the idea being that in due course I’ll start with corals down that end in high concentration (the tank has been set up to reef quality) and gradually move it along the tank as I can afford more lighting!

Stocking (this is where I become less sure – my dad stocked the tank while I was away at university)
About 50kg of live rock (I think)
2x green chromis
1x silver bellied wrasse
6x deep blue yellowtail damsels
2x common clownfish
1x bi colour blenny
1x large clownfish (needs properly id-ing!)

I need some advice on powerheads and what to get, the ones I’m using now are inherited and obviously not effective enough! Any tips?
Any questions at all just ask – I wish I’d kept a diary throughout but unfortunately a bunch of shoddy photos is all I’ve got for my hard work! If you want any other photos again, just ask and I’ll upload them as soon as I can.


Looks good, make sure that wiring used doesn't contain metal as it will leak unwanted minerals into your water (including copper if it contains it which is a big no no in reef tanks as its fatal to inverts.) as for powerheads, I would recommend 3x hydor koralias magnum 7's... or 4x magnum 6's. that will be plenty of flow and wont break the bank or 2vortech mp40's depending on your budget (will break the bank for me)
Hello and Welcome!

1. The clown is a tomato clown. You can normally only have two clowns per tank, but your tank might be large enough to get away with 3. Normally they will fight until its down to the same species pair or the other clown.

2. You can only have one small fish for every 40 L (or 1 fish for 10 gals) so you have plenty of room for more, but there is a limit.

3. The damsel fish you have in there are very likely to kill any other fish you add to tank, the existing fish and themselves until you are left with the biggest and meanest one left. They are notoriously evil monster and I would suggest removing them.

4. It looks like you have a white nem in there, which is very sick. No healthy nem should be that white. Im not sure if you bought it that way, considering LFS love to pass off sick creatures to the uneducated hobbiest, but I would either return it or dedicate yourself to healing it - which will take some work. Nems require very high lighting conditions, higher than corals, and pristine, stable water conditions. Normally the last two requirement arent found until the tank is around a year old. What kind of lighting do you have on the tank?

5. I would remove the bioballs. Unless you clean them pretty frequently they just become nitrate factories. I would also skip the deep sand bed, they can easily crash a tank if they become disturbed. Just a few pieces of rubble rock and cheato (like you have) will serve you well.

6. Looks great! Good job with the build!
thanks everyone for the messages. its taken a long time to get to this stage but i've still got a lot of work to do/a LOT of things to learn!

@buddy - i've had a few invert deaths which would be explained by this wiring. If i'm able to replace the wiring is there anything i'd be able to do to remove the copper/excess minerals? i also have stainless steel rings that i use to tighten the pipe around the return pump, will these need to be replaced?

@little_fish - so far i've had no signs of conflict. Hopefully it'll stay that way although if there is arguments coming from the damselfish i'll remove them asap. re: the nem - its fake! when i purchased the 2 clowns they were in a tank with anemones, i popped this in in case they were raised with one (tank bred) but they haven't touched it and certainly don't look at all stressed (the tamest fish i've ever owned). about the bioballs, at the moment my tests are near perfect (nitrate is 0.25 from memory) but again if nitrate becomes an issue i'll remove them straight away.

Nitrates should be at zero, but you can leave them in if you wish. Just be sure to clean them with every waterchange. And im glad to hear the nem is fake, otherwise that would be a very sick animal :) And as you can see, there is no guarantee that the clowns will be hosted by it anyways. The clown name is well deserved.

The stainless steel shouldnt be a big issue, but if you have copper in the tank it might be impossible to keep inverts because its extremely hard to remove the copper from the tank once it is in there.
first thing you need to do is have your water tested for copper, there could be other reasons for their deaths but if your water contains traces of copper, thats the direct cause. I would recommend gutter guard instead, its plastic and used to keep leaves and debris out of rain gutters and can be found at most hardware stores; or bought online.

if you do have copper in the tank, the only thing i can think of to correct the issue is start over. move the livestock to holding tanks, replace the sand, and rinse the live rock with a hose thoroughly and let dry. afterwards, then you should be safe to start building your reef again.

as for the stainless steel... to be safe, I would remove it and use zip ties instead
And im glad to hear the nem is fake, otherwise that would be a very sick animal :) And as you can see, there is no guarantee that the clowns will be hosted by it anyways. The clown name is well deserved.

I bought my two nems online and when they were delivered they were both bleached at first but they regained their color. Being bleached doesnt meant they are sick and about to die.
Amber, I realize that. You should also realize that in another persons care they could have died, you however were informed about them and you took the correct steps to help them regain their health. Not everyone is a lucky and as smart, and well informed as you.

Also just drying the rocks and sand wont remove the copper that is in them. Once copper is in the rocks, its basically in there permanently. You would have to get all new rocks and sand.
even after rinsing them thoroughly? The sand would be replaced, thats the easy one but the rock not so much. I could assume after enough rinsing and soaking in clean fresh water that the copper traces would vanish just like it would if someone was to bleach there rocks with bleach.
Nope, to remove the copper you actually have to soak them in acid, and then you have deal with the effects of dunking the rocks in acid
That would be in the case of him actually having copper traces in his water, we still dont know yet. It takes a lot for copper to disperse into the water from metals. I experienced it first hand when my pin cushion urchin ate through my digital thermometer cable; I had an exposed copper wire in the tank for who knows how long before I discovered it and luckily my water tested with 0 copper. Have your water tested cadgey and let us know the results; that way we can point you in the right direction. Hopefully, you dodged a bullet like me. Fingers crossed :shock:
i suppose theres nothing for it but to cross my fingers and test for copper.. so annoying; i've been using aquarium safe materials at every turn!
just another thing guys, its my understanding that a live rock only tank requires less flow than a reef tank, if i was starting with coral up one 'end', would i be able to 'get away' with stronger pumps in just that end? i didnt budget for an extra £300-400 in start up costs!
that is a total myth, you need lots of flow no matter the type of tank. The ocean is never still and neither should your tank. A minimum is 25x per hour, but i personally think the fish and corals are healthier at 40x per hour.
Sorry everyone for the late reply and keeping everyone on tender hooks (!); I've just moved back to Uni so a lot of non-Marine work to keep me busy!

Before I left I tested for Copper and [thank God] it tested 0. My dream of a Reef tank is not yet dead!

I haven't seen the tank for about a month but apparently the water is testing 0.25 for Ammonia whilst tests 0 for all other results (and at stable levels for PH, Temp, Salinity). Would this be why any inverts in the tank are not lasting particularly long?

could be but it could also be just inverts dying. I would get a second opinion on the test kit, some test kits can be deceiving or inaccurate. especially the api ones, mine reads .25 ammonia as well but my tank is over a year old and has always read that throughout its cycle till now. My lfs test read 0 ammonia so I know my kit is faulty.
fortunately i retested when i was home for the weekend and everything seems to be reading what it should.

a quick question of stocking, so far the tank has:

1 bicolour blenny
2 blue chromis
5 damsels
2 clown
1 tomato clown
1 silver belly wrasse
1 yellowhead sleeper goby
1 small blenny

what sort of limits are we looking at?
thanks again,
rule of thumb for stocking is 1 fish per 10 gallon ( 1 fish per 40 litre)so you would be looking at about 18 smaller fish.. I would really see if you cant get rid of the damsels and get a couple nicer fish in their place... Extremely mean fish that may kill any newcomers..