Toxicity (or other) risk? Tin foil / aluminum foil as hood lighting reflector

[nobo]

I made some DIY reflectors from tin foil/aluminium foil to go under the black hood/black flaps/behind the lights of my Juwel Rio 125.

It’s now occurred to me that this may be a terrible idea, as there’ll inevitably be some condensation on the foil, which will drip back into the tank. Which made me wonder about whether this was safe or potentially toxic to my tropical fish (and shrimp). And whether heat reflection is an issue e.g. for bulb life.

Research so far seems to suggest I’m outside the pH danger zone (c. pH 7.5 but hard to be very precise - it could be under 7.3 I guess) since aluminium reacts in acidic water, causing problems (see links below).

An alternative would be to paint the underside of the hood and flaps white in aquarium safe paint. (I appreciate that there’s debate about which material is best as a reflector – white paint vs mylar vs foil etc but happy to leave that can of worms closed, not least as I’m looking for some improvement rather than perfection.)

Or have no reflectors - I'd prefer that over the risk of poisoning the livestock!

I’m probably overthinking this and the foil is probably fine (I’d guess the amount that drips back is negligible, and with c. 50% water changes every week or two, etc….) But don’t want to poison my fish. Thoughts?

Some of the better links I’ve come across in my reading:

https://barrreport.com/threads/may-aluminium-foil-be-toxic-for-fresh-water-shrimps-and-fish.5856/

http://www.simplydiscus.com/library/disease_medications/external/aluminum_toxicity.shtml

I can take a photo if that'd help.

 

[Colin_T]

If you have a coverglass on the tank, there won't be any moisture getting onto the light and running back into the tank.

Aluminium foil that is used for cooking is safe for fish, unless you wrap the fish in it with some lemon, butter and spices and cook it.

All reflectors do hold some heat in and this can shorten the life of fluorescent globes. If you drill a 10-20mm hole in the ends of the light unit, a lot of the heat can come out and you get cooler air flowing over the end parts of the globes.

 

[nobo]

If you have a coverglass on the tank, there won't be any moisture getting onto the light and running back into the tank.

Aluminium foil that is used for cooking is safe for fish, unless you wrap the fish in it with some lemon, butter and spices and cook it.

All reflectors do hold some heat in and this can shorten the life of fluorescent globes. If you drill a 10-20mm hole in the ends of the light unit, a lot of the heat can come out and you get cooler air flowing over the end parts of the globes.

Thanks Colin.
There's no coverglass, just the black plastic top unit (2 flaps, with a central bar housing the lighting). I've lined the flaps with foil too. The foil definitely collects moisture, which drips back into the tank, so was a bit concerned (given some of the other comments about aluminium) that this might be an issue (not quite as bad as putting aluminium foil directly in the tank, but ... ).

I think there's still reasonable air circulation, as there are some gaps in the lid.

I'll spare them the butter, lemon, herbs and spices

 

[Colin_T]

If the lid is plastic you can drill some holes in it to let the heat out. This should take out some of the moisture too.

 

[Essjay]

Or just leave one of the flaps open. That's what I did with my Rio 125 when we had the occasional heatwave.

If you are worried about DIY aluminium foil reflectors, you could always buy Juwel's reflectors