Who Gives A Fish Forums

My tank's been cloudy for days, and I can't figure out why. I've got a 20-gallon with sand substrate, a sponge filter, and a bunch of Java Ferns. Water params are good, 0 ammonia, 0 nitrite, 10 nitrate. Any ideas what's messing with my water clarity?

Cloudy water's usually a bacterial bloom or fine particles. How often do you do water changes? Sand can hold debris if it's not rinsed well. Also, check if your filter's flow is strong enough to keep things moving.

I had the same issue last month. Turns out I was overfeeding. Cut back on food and did small water changes every other day, and it cleared up in a week.

Cadix wrote: ↑Mon Aug 04, 2025 7:05 am Cloudy water's usually a bacterial bloom or fine particles. How often do you do water changes? Sand can hold debris if it's not rinsed well. Also, check if your filter's flow is strong enough to keep things moving.

I do weekly 25% changes, but the sand was rinsed. Maybe the filter's too weak? It's a basic sponge.

A sponge filter alone might not cut it for a 20-gallon. Try adding a small HOB or powerhead to boost circulation. Also, if you're overfeeding, that'll fuel the bloom. Floraka's tip's solid.

Yeah, less food and more flow worked for me. My tank's smaller, though, so maybe PetmanY needs a bigger filter upgrade.

floraka wrote: ↑Mon Aug 04, 2025 11:53 am Yeah, less food and more flow worked for me. My tank's smaller, though, so maybe PetmanY needs a bigger filter upgrade.

Exactly. A stronger filter'll help suspend particles for removal. Also, consider adding some Purigen to your filter media. It's great for polishing water.

Thanks, gonna try a HOB and cut back on food. Appreciate the help, y'all.