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I've got a 20 gallon planted tank with about an inch of Fluval Stratum. My Cryptocoryne Wendtii isn't spreading like I expected. Could the substrate be too shallow for root growth? I've got moderate lighting and dose liquid ferts weekly.

An inch might be cutting it close for Crypts. They're root hogs. I'd add another half-inch at least, or they'll just kinda sit there sulking. Stratum's great, but it compacts over time, so keep an eye on that.

My tank has shallow substrate too. The plants grow slow but they're alive. Maybe try root tabs? I use them sometimes.

fizzler wrote: ↑Fri Jul 25, 2025 9:44 am An inch might be cutting it close for Crypts. They're root hogs. I'd add another half-inch at least, or they'll just kinda sit there sulking. Stratum's great, but it compacts over time, so keep an eye on that.

Yep, second this. Crypts need depth to stretch out. If you're worried about aesthetics, slope it toward the back.

I had the same issue with my Amazon Swords. Added more substrate and they perked up in weeks. Maybe your Crypts just need room to breathe.

Thanks for the tips, everyone. Gonna grab another bag of Stratum and slope it like bajil suggested. Appreciate the help!

Good call. Post an update when they start spreading. Crypts can be drama queens, but once they're happy, they'll take over.

Do you think sand caps work with Stratum? I've heard mixed things.

coralhaven wrote: ↑Fri Jul 25, 2025 3:16 pm Do you think sand caps work with Stratum? I've heard mixed things.

They can, but it's sketchy. Sand chokes the Stratum if it's too fine. If you're gonna try, use coarse sand and keep it thin.

I've seen people use gravel over Stratum for better root anchoring. Might be worth experimenting if the sand doesn't pan out.