hi, ive had an african tank running for about 3 months going really well, but in the last 2 weeks the bright white coral which cost me a fortune is developing brown spots, but only on the coral, not the sand or glass. the fish seem to enjoy nibbleing it but i think it looks fricking ugly, the water is crystal clear with no odour, tank is out if direct sunlight, can i stop this with an algaecide or something? i expected the coral to go a bit green but didnt expect brown spots

Only way to keep the coral white is taking it out and boiling it and scrubbing it every time it goes brown IMO, Im not sure if it can be prevented. Maybe less time having the lights on would slow the growth. My tank is full of coral rock and is all types of green and browns but I like it because it looks more natural.

true, it does look more natural, ive heard of soaking in a bucket with vinegar over night is another way. probably not as cost effective as boiling though, id need alot of vinegar. thanks for your reply

true, it does look more natural, ive heard of soaking in a bucket with vinegar over night is another way. probably not as cost effective as boiling though, id need alot of vinegar. thanks for your reply

Soaking it in vinegar will dissolve the outer layer off. Vinegar is an acid.

I used to pour boiling water over mine, and then soak in a bucket with a small amount of bleach. Did this many times with no issues, and they came out nice and white. Just rinsed off well, and final rinse with water double dosed with prime to get any excess chlorine.

Can't be bothered now and don't do anything.

I did have algae issues with mine when I first setup a tank with it but it seemed to disappear, as with all algae watch your light levels and what you feed etc, also some fish that dig around in it more will tend to turn it over more so. Brown algaes are also very common in new tanks so it might clear up.. In saying that when I tried silica sand that went manky and brown and I couldn't find anyway to get rid of it

We had a type of brown algae in our African tank and we added a few golden algae eaters which seemed to fix the problem. I had read on an internet site that they can be an option when combating brown algaes, GAE can be aggressive though and do get quite large.