Who Gives A Fish Forums

My tank's phosphate levels are through the roof, and I'm not sure what's causing it. I've been doing weekly water changes, but it's not helping. Any tips on how to bring it down?

Phosphate spikes can come from overfeeding or decaying organic matter. What's your feeding routine like? Also, check your filter media, it might be trapping excess nutrients.

I had the same issue last month. Cut back on feeding and added some fast-growing plants like Hornwort. They suck up phosphate like crazy. Also, check your substrate, detritus can build up there.

Phosphate is often linked to overfeeding or low-quality food. What brand are you using? Some cheaper foods have fillers that break down into phosphate. Switching to a higher-quality pellet might help.

Yeah, I agree with the plant idea. Floating plants like Duckweed or Water Sprite are great for nutrient export. Just be careful, they can take over if you're not careful.

Thanks for the advice, everyone. I'll try cutting back on feeding and adding some plants. I'll also test my tap water to see if that's the culprit.

rockstar2 wrote: ↑Thu Jul 03, 2025 6:44 pm I had the same issue last month. Cut back on feeding and added some fast-growing plants like Hornwort. They suck up phosphate like crazy. Also, check your substrate, detritus can build up there.

Hornwort is a great suggestion. I've also had success with Anacharis. It grows fast and doesn't need much light.

If you're gonna use a phosphate remover, make sure to monitor your other params too. Some removers can mess with your pH or hardness.

Another thing to consider is your water change schedule. If you're only doing small changes, it might not be enough to dilute the phosphate. Try increasing the volume or frequency temporarily.

I've found that reducing light duration can help too. Less light means less algae growth, which can contribute to phosphate buildup.