I'm making a DIY background with polystyrene and layers of concrete. Possibly mixing in some acrylic paint, cause I have no idea where to find cement paint or something to colour it. What can I use as a sealing final layer?

More importantly, where can I buy it? How much is it approximately?

I have minimum experience with these things, and all the videos and tutorials use american products. I have read many things leak toxins into the water, so I want the safest thing possible. Not "marine-grade" things as I've read they aren't safe over a long time.

Any help?

Thanks in advance if anyone can help me.

I've read through some of the posts here on DIY but I need to know where to buy these things, and what is best.

Normal house paint did mine, still in the tank after 3 yrs

Just outdoor paint? Did you use any special kind?

I'm not sure if I want to use this, just in case, because it is for a baby axolotl tank, and they are extra sensitive. I will keep the option in mind though, cause I don't know what better luck I will have.

Have you noticed any cracking or peeling? pH spikes or anything with it?

What makes axys so sensitive?

have used this with frogs and also marines

I'm making a DIY background with polystyrene and layers of concrete. Possibly mixing in some acrylic paint, cause I have no idea where to find cement paint or something to colour it.

Mitre10, Bunnings. Should have concrete pigment, I know I've seen a variety of colors at mitre 10 here.

ce-mix do a range of products.i used quick patch,multi bond and aqua stop.to colour it they make oxides .i used all these over polystyrene.mix up a slurry paint it on with a paint brush,many light coats.no need to seal it thats what the aqua stop doesthese were designed to do water tanks and ponds i think,cant remember what was on the containers.mine has been in with my africans for about 3 years.no problems at all. only issue i had,and it was my mistake,not the products. was put plenty of coats on to get a good thickness as when a rock or something damages it you get a white hole showing.i only did about 4 coats,in hindsight i should have doubled that number.all availiable at bunnings.

Ok thanks for all your input everybody

I had a wee look at Mitre 10 for concrete pgiment but couldn't really find anything. I was probably in the wrong section.

I'll check Bunnings as well, and see what I come up with.

Appreciate all your help!

Also, axies as a whole aren't too sensitive, but their babies are. My background is for my young ones tank, so want it as safe as possible.

rear mine from hatching on tap water