My big malawi tank project

[alanmin4304]

Another way would be to just put the tubes and reflectors into the lid and and wire the rest up remotely. Takes a lot of weight out of the lid and a lot of mains wiring away from the water.

[elusive_fish]

I still think you could have the hood made in a few pieces so it was an easy lift you won't need to get into the tank very often and would most likely be doing that when customers aren't around anyway I would think..

I will be doing it after hours, on my own. Even if the hood is light, one person cant handle something 2.3m x 0.7m. I guess I could get someone to help me before they go home, but im just trying to make my ongoing maintenance life as as easy as possible.

Lighting just buy standard lighting battens from mitre10 or even building recyclers or trademe and stick the right bulbs in them, they wont be T5 but still plenty bright enough if you get some 10k and maybe a blue one, inside your hood you have the room to do 2 banks of them if you want it brighter anyway. You can get an engineering company or maybe someone you know to fold up some ally or something like that to make reflectors for them. Or stick something to the entire underside of your hood, paint it in silver paint or something like that, I have even heard of people using tinfoil but that is probably a little too hori and rough for this job. Building paper might work?

Would a single strip of t8 lights either side do the job? Ie 2 x 4ft and 2 x 3ft for the whole tank? Interesting idea about painting the inside silver. The custom reflector idea is a good one, but by the time ive paid an engineering firm to cut and bend aluminium to size I may as well ahve spent that extra money on one-piece aquarium lighting.

[elusive_fish]

The standard bought lighting "units" will come with reflectors inbuilt. They always do. brands include arcadia, hagen and so on...

Know of any cheap sources for these? If I can find a low enough price this would certainly be my preferred option.

[elusive_fish]

Another way would be to just put the tubes and reflectors into the lid and and wire the rest up remotely. Takes a lot of weight out of the lid and a lot of mains wiring away from the water.

Great idea. I'd imagine I could get the ballasts from a lighting or electrical store and the reflectors from a pet store.

My sisters bf is an electrician - if he is willing to help it would be a great option. Shame he ..er... suffers from inertia

[MarkLB]

Shame he ..er... suffers from inertia

:lol: Are you saying his motivation goes up in smoke? :lol:

[Jennifer]

Why can't the lights be attached to the lid which lifts on a hinge, like those red sea max tanks (I think it was those tanks anyway :roll: )? That way the whole light rack would just flip up from the hood so you wouldn't have to remove it for most tasks.

[ryanjury]

If you know a sparky then ask him he will no doubt have access to reflectors.. I would say a strip on each side would be plenty obviously get the right spectrum to achieve what you want and I would say you will grow heaps of algae. Could be expensive to get someone to make up the bits you want, but if you shopped around you may find someone with long thin offcuts that aren't good for much else they may do a cheap job for you.

I was meaning making the hood in several pieces that all join together ie 3 766 x 700 pieces that are just sitting on the top then you could just lift or slide them off. A friend of mine has a 8 x 3 x 2 and we had to take the lid off her tank the other tank it is one solid piece and takes 3 people to slide it off the front and sit on the floor so definitely not a practical way to go.

[oneeyedfrog]

You can get reflective film - I think its called mylar from switched on gardener.

Jenniferh- I was thinking the same. I have seen pics where the whole lid can lift up out of the way and has stays to hold it up as well as a hinged piece that you can lift for feeding etc.

This guys has all these holes/fans for ventilation which shouldnt be needed with standard lights

[ryanjury]

That is a very well designed hood, lol imagine what you could do with some car gas struts..

[trace&steve]

awesome its coming along lovely :bounce: :bounce:

[Jennifer]

Holy cow that is an awesome hood! Just what I was thinking for my new tank.....

[phoenix44]

Those sort of hoods are commonly used for marine setups. A point to consider is condensation. It is best to use a glass lid on the tank, even with a hood like that, and then make sure you design a drip plate if the tank does not already have one. course then you lose some of the light as it reflects off the glass, and passes through it, and then the water. With a tank that high, I do not think you can afford to lose any more light. For the display to look right, you will need the tank to be brighter than its surroundings, and that will be hard to achieve if you don't get lights that are powerful enough.

if the tank is dimmer than the surrounding there is no point lighting the tanks. That is why ALL fish shops have the aquatic section dimly lit with the tanks well lit.

[elusive_fish]

Of course there will be a glass lid on the tank.

Sorry if im being slow, but im still trying to figure out why a hood is a better idea than suspended lighting. The main point seems to be around security of the tank ie the fish not being fed muffins. I cant imagine that would happen too often - there will be bar surface width 40cm aroudn the outside of the tank and the top will sit at about 150cm. Kids wont even be able to get access to the top to put things in.

P44, would your double T5 lights do the job suspended above the tank?

[phoenix44]

P44, would your double T5 lights do the job suspended above the tank?

I think t5 HO's will be fine, yes - but ill leave someone less biased to answer that question :lol:

[elusive_fish]

Ideally I'd like to put a strip of T5HO on either side of the tank ie 2 x 4ft and 2x 3ft.

There really dont seem to be simple, single bulb units out there. Makes me lean towards buying the ballasts and reflectors and installing it either in a hood that sits on the tank, or one that is suspended above the tank.

Man, this project is driving me bonkers

[phoenix44]

Ideally I'd like to put a strip of T5HO on either side of the tank ie 2 x 4ft and 2x 3ft.

That would be a very professional way of doing it, easy and no messing around. your standard business insurance should cover it too, and you should be able to depreciate it as a company related expense. Thus gaining a tax shield.

I doubt you would be able to depreciate a DIY light hood, and for it to be insured it would need to be installed by a registered electrician.

[elusive_fish]

I know this is a weird detail to get caught up on, but can anyone please help me with this question.

The cement covered polystyrene background looks reasonably light and quite 'patchy' when dry. When wet, it is dark and the colour inconsistancies are unnoticeable. It looks much nicer when wet.

How will it look when submerged and under strong lighting? Case in point: my neighbour used local beach sand in his aquarium. When dry, the greywacke sand is quite a light grey but goes much darker when wet. Thinking it would look 'wet' in the water he was disappointed when it looked closer to the 'dry' colour.

Its seems that wet things viewed in air look darker than when they are submerged... will this be the case or am wrong?

[elusive_fish]

OK, time for my next random question(s)

The tank is to feature a 'rock' wall running down the length of the tank, in the middle. There are diagonal holes carved in it so that the fish can weave their way in and out of the rocks, from one side of the tank to the other.

Because it is polystyrene covered in cement, its incredibly buoyant and im concerned that there won't be enough surface area on the bottom of the feature to anchor it down to the aquarium safely.

The wall is 2100 Long x 450 high x 80-150 wide. There are a number of cut outs along the bottom, meaning that the total surface area where it would stick is considerably less than the 2100x80-150 footprint.

Questions:

1/ Should I cement or epoxy resin the polystyrene on the bottom of the wall, where the tank will be stuck down? Or would leaving the bare poly be better for the adhesive (presumably silicone)

2/ Will there be enough surface area to hold it down without the glue or the poly failing?

Here is my (probably flawed) math if anyone can tell me if im on the right track!

Best guess, this thing has a volume of about 90l. It probably weighs 10kg, but displaces 90kg of water... so it will have 80kg/785N upward force. The bottom surface is nominally 2.1 x 0.1 = 0.21 square metres. But as roughly half has been carved away, this leaves 0.1 m^2.

Therefore, the rock wall will experience 7850N/M^2 (Pascal) of pressure/stress. Now that I've worked that out, I have no idea what to do with it :lol:

[spoon]

i would use cement over the poly then silicone it down but in saying that if its flat cut poly on the glueing surface - not crumbly carved up stuff then you should be fine the most important points being that everything is perfectly dry and clean when you start and use a thick bead so you have a big area of silicone then give it plenty of curing time before you add water. another option would be to melt out the poly with a heat gun to reduce bouyancy but then you would have to do that in an ares that isnt being siliconed or make a new bottom for it afterwards from some other material

[elusive_fish]

I've pretty much done what you described. The bottom surface has not been cemented, nor shrunk with the heat gun. Its just expanded poly. Do you think it would help the strength if I epoxy resined the bottom? I'm just wondering if the silicone would stick better to that.

If you plan on being over the new brighton way somewhere in the near future you should let me know and come take a look and let me know what you think.

[spoon]

could do a detour 2moro as i got to go to that side of town and im off work

[elusive_fish]

Ooh! Im excited about a trademe auction I just saw... a male giraffe at 10cm. Don't anyone go bidding on him!

Would he be ok in the tank im planning with electric yellows and dems juvis?

[ryanjury]

lol he would love them and probably eat juvvies, of course that would be depending on their size etc.. I would start with a smaller giraffe and let them grow up together..

[elusive_fish]

I know they are predatory, as are most fish given the mouth-to-prey size ratio works for them

Most juvies I see sold are the 2-3cm mark. Surely he couldnt eat those?

[ryanjury]

I know they are predatory, as are most fish given the mouth-to-prey size ratio works for them

Most juvies I see sold are the 2-3cm mark. Surely he couldnt eat those?

lol famous last words Giraffes like all nimbos are predators mine haven't been so far and have just left fish alone but I wouldn't put it past them to eat anything they can get and I certainly wouldn't bank on them not eating a bunch of 2-3cm fish when they are 10cm long..