Ok so my initial greenwater tub failed, it never grew enough free floating algae before i had to do a water change (ammonia just kept going up too high). But now we've moved into a unit and i have a nice verandah just screaming "FILL ME UP WITH GREENWATER TUBS" so on my holidays that is my plan

I have 1 concern though... there are many birds around, viscious angry birds that would rip a peice of chickenwire/screening off the tub without a second thought. We're talking kookaburras, magpies, butcher birds (their name rings true for their temperment), etc. They are angry buggers and would love a feast of my fishies! What do you reckon i could use to top the tub but still let enough light in?

I would do an indoor tub but we're saving for a home deposit and i cant spend anymore money on fish stuff

I have a 2x 20gallon tubs which are my QT/hospital tubs and i plan to use with a broken internal filter to supply air (its only the powerhead + air attachment, no actual filtration component). I think all i need to figure out is how to top the beast.. anyone got some ingenious ideas? Something cheap

I was thinking glass, but i only have a piece that will cover 1/2 the tub... and glass is expensive.

What about plexi-glass? Anyone got any idea on how much that is?

Also does glass/plexi-glass filter out any of the rays i need for the greenwater?

Plexiglass tends to be much more expensive than glass - at least in my experience. As it heats up in the sun, it will sag. You would need to go with a much thicker piece of material - most likely lexan - and that will be VERY expensive.

Glass breaks.

What about a wooden frame with hardware cloth for the top? Hardware cloth is the heavy wire mesh - usually about 1/2 inch squares. You can build a wooden rectangle of 2X4s with four feet that hold it over the tub, but will prevent it from being flipped off the top of the tub by the birds. Staple or nail the hardware cloth over the rectangle top frame. Hardware cloth is strong enough to repel even the most determined raccoons here..... I doubt the birds could rip it. And, with the legs, I think the frame should remain in place. You will be able to see and feed the fish through the wire mesh, but it is small enough that no beaks or claws can get through and strong enough that it cannot be torn.

Well i've had butcher birds tear chicken wire off a chicken cage (as in break it).. but this stuff is stronger yeah?

I'll take a stroll down to bunnings on my holidays and see what i can find

Chicken wire is rather thin wire that is twisted together. I can rip it apart with my bare hands if I try. Hardware cloth is much heavier wire, welded (I think) together in a 1/2 inch (other sizes available) grid. It is strong stuff. I have had it defeat the most determined raccoons - they are HORRID pests......

hrmm oky doky, i'll check it out! thanks