Backyard Aquaponics
A place to discuss aquaponics

Hi,

Due to the recent arrival of a baby I need to cover my fishtank.

It's basically an open top poly tank sunk into the ground like a pond 1.8m across.

I am thinking of making a wooden lid, of octogon shape.

Possibly with a hinged door in the middle.

Does anyone have any suggestions on suitable material?

I was considering treated pine from bunnings or similar.

I've read the thread at:
viewtopic.php?f=8&t=16671

Which had a couple of ideas but didn't appear to come to a conclusion.

Cheers

Untreated hardwood is fine, don't use treated pine unless you paint it thoroughly.

if the fishtank is under cover and providing the treated pine doesn't get wet it would be ok.. otherwise no I wouldn't use treated pine as a cover for the FT. it will leach out things like arsenic & pesticides into the FT. I don't even trust this eco-wood they sell and claim its ok for the environment,.
I would use plain old KDHW, (hardwood.) it will last many years outside without being painted or you could oil it with linseed oil and it would last a lot longer... if you do oil it, leave it in the weather for a couple of weeks on the ground so it gets time to dry off.....
I was thinking of merbau decking but that would only leach a lot of colour into the FT... so that wouldn't be much good..unless you can find some very old decking boards. other than that get some concrete Reo and cut it to the shape of the FT. 120mm/120mm square hole is classed as child proof.

Use Aluminium sq tubing for a frame (s) and then cover with .....gawd seniors moment.....the corragated clear or tinted stuff used on pergolas like corro iron but poly/plastic fiberglass type stuff. and paint the underside with quality paint.

Light to handle
Fairly safe to walk on.

lmao@tonzz

Look what I found Tonzz.....>>>>>>>>>>>>>>>laserlite ..


is that what your were looking for.

Oh thank you dear master, bloody young whipper snappers.Actually I have done an 800K drive today get back home, raging headache but cant leave this forum alone.

We have 3 kids including a 7 month old baby and are setting up our first AP system.

I was planning on using rigid galvanized metal mesh like cattle guard to make a FT cover.... Just like they do for ponds.

Using cable ties to attach shade cloth so that the fish are shaded. With a hinged (and lockable) "door" near the edge for maintenance and feeding etc.

It's going to be heavy to lift on and off but I think it's the safest option to prevent both accidental drowning and stop the little monsters putting rubbish in the tank.

Might put some clear laser lite over the door to act as a viewing window.

Thoughts?

If it rains a lot on it, and Sydney has fairly acid rain due to the pollution, the Zinc will be dissolving and dripping into your water, which is no good for the fish. How long it would take to poison them, I have no idea.

will probably need a frame. Mesh along would tend to sag and you don't really want to buy higher grade mesh anyway as it becomes heavy, plus maybe the zinc issue above (less issue). At that point you will probably find that a beam across the diameter of the FT and then some lighter material and a basic frame will work fine anyway.

With kids the main issue will be securing it down and it being strong enough in case they climb on top.
Little rascals will soon figure out most systems.


[edit] Crazytree - a beam across the middle would be option for your 1.8m poly tank as well.
can hinge at beam and easy to lift and access. Span and sag become less of an issue then.

I forgot to mention we are putting the fish tanks in a shed so rain is not so much of a worry - but I guess splashing from the fish/condensation would do the same thing.

What about creating a grid from pvc pipes/conduit and securing it to the tank with shade cloth attached?

Could still do the central beam idea and the hinged door/flap.... But a bit lighter than metal grid?

Yes if thje gal can be splashed, or have condensation drip off it, its best not to use it... although I notice Costa on Gardening Australia on Saturday was fixing up a disused, overgrown AP system, which appeared to have a gal grid cover on it. I'm not sure how long the Bass he introduced will last.

PVC + fittings would be expensive to do in pipe that would be strong enough to hold a rampaging child

What about a strong fishing net or similar?

Hahaha not planning to build a deck on top of the FT for them to dance on lol

whatever I build just has to be strong enough to hold the kids back so they don't drown. I'm thinking even electrical conduit lashed together with (as you said) a strong fishing net or similar over the top would be enough. Conduit is only $2-$5 per length. The shade cloth was mainly for shade and also to stop mini people throwing pebbles etc in the tanks.

We received an old driveway gate FOC that will be installed across the shed opening (since the sliding doors are stuffed) and this will be locked most of the time - the covers on the tanks are just extra precaution.

A friend of ours little boy is part monkey and has figured out how to scale their aluminium pool fence... No help just shimmies up those skinny vertical aluminum poles like they're a ladder...

Suffice to say they are now forking out big bucks for glass pool fencing.

I swear - some kids seem to gravitate towards danger!

I don't really think there would ever be enough condensation or splashing for the gal to be an issue, but if you're worried, I'd just paint it.

Good timing, I'm designing a lid for my poly FT which is 2.5m across. I have a local sawmill that offers rough sawn cypress to practically whatever size you like. Untreated and safe in ground, so it should be fine above the tank.

At this stage I'm thinking 100x50mm bearers in a H-pattern over the top of the tank with hinged doors on the top/bottom of the "H". That should minimise the span distance asa single bearer of 2.5m at the widest point will probably sag - unless I laminate two bearers together. The H pattern will be more stable and easier to create some pitch for rain water run-off.

Marine ply for the doors (no frame required) and cover the rest of the lid in waterproof shade cloth which is about $14/m from the big green shed. I'll notch the two bearers to fit over the poly pipe around the rim of the tank.

Here's a top view of my tank before it went into the ground, to give you an idea.

I'm curious about the poly pipe around the rim of your tank. What size did you use and how did you attach it?