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I've had a moss ball for about six months now, and it's starting to turn brown in spots. My tank is a 20-gallon with moderate lighting, and I do weekly water changes. Any idea what's causing this?

Moss balls can turn brown if they're not getting enough light or if the water quality's off. What's your nitrate level? Also, do you ever roll them to keep their shape?

I've had the same issue before. It could be too much direct light or buildup of debris on the surface. Try gently squeezing it during water changes to clean it. Mine bounced back after a few weeks.

Yo, moss balls are chill but they hate stagnant water. If your flow's too low, they'll collect gunk and go brown. Maybe bump up the filter output or give 'em a lil swirl now and then.

Mine did that when I overdosed ferts. Cut back on the liquid stuff and it greened up again. Also, keep an eye on your temp, they prefer it cooler.

limber wrote: ↑Sat May 17, 2025 8:10 am Yo, moss balls are chill but they hate stagnant water. If your flow's too low, they'll collect gunk and go brown. Maybe bump up the filter output or give 'em a lil swirl now and then.

That's a good point. I've noticed mine do better near the filter outflow. Maybe try repositioning yours?

Brown spots often indicate decay. Trim the affected areas with clean scissors and ensure your water params are stable, especially nitrates below 20 ppm. Rotate the ball weekly for even light exposure.

Moss balls are tough but fussy about water changes. If you're using tap water, check for chlorine. I switched to RO and mine perked right up. Also, they love colder tanks, like below 76°F.

Mine went brown when I neglected rolling 'em. Gotta keep 'em round or they'll flatten and rot in spots. Now I give 'em a gentle squeeze and roll during water changes, no more issues.

Agree with the flow advice. Low circulation lets detritus settle on them. I'd also check your photoperiod, 6–8 hours of moderate light is plenty. Too much and they'll bleach or brown.