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I've got a 20 gallon planted tank with a HOB filter, and my plants aren't thriving. The flow seems strong, but I'm not sure if it's the issue. Tank has Anubias, Java Fern, and some floating plants. Water params are good, 0 ammonia, 0 nitrite, 10 nitrate. Light is on for 8 hours daily. Anyone else dealt with this?

Strong flow can mess with some plants, especially floaters. My Frogbit kept getting pushed under with my old filter. Maybe try redirecting the flow or adding a sponge to soften it?

Yep, HOBs can be rough on delicate plants. I switched to a sponge filter in my 10 gallon, and my Anubias perked up. What's your substrate like? If it's bare bottom or sand, roots might not be anchoring well either.

northstar wrote: ↑Thu Aug 07, 2025 9:15 pm Strong flow can mess with some plants, especially floaters. My Frogbit kept getting pushed under with my old filter. Maybe try redirecting the flow or adding a sponge to soften it?

Totally agree. I use a pre-filter sponge on my HOB, and it's a game-changer. Also, floating plants like Salvinia might handle flow better than Frogbit.

Your light might also be a factor. Anubias and Java Fern are low-light plants, but 8 hours could be too much if the flow is stressing them. Try reducing light to 6 hours and see if they bounce back.

I had the same problem. My filter was too strong, so I angled it toward the glass. Plants started doing better after that.

What's the filter model? Some HOBs have adjustable flow rates. If yours doesn't, you could baffle it with a plastic bottle cut to shape. Worked for my Betta tank.

My plants didn't like strong flow either. I moved them to a quieter part of the tank, and they're happier now.

Blazer88 wrote: ↑Thu Aug 07, 2025 11:12 pm Yep, HOBs can be rough on delicate plants. I switched to a sponge filter in my 10 gallon, and my Anubias perked up. What's your substrate like? If it's bare bottom or sand, roots might not be anchoring well either.

Sponge filters are clutch for planted tanks. Less flow drama and better bio filtration. What's your tank temp? Cooler water can slow plant growth too.

I'd try the sponge trick first. Cheap fix and worth a shot before swapping filters.