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I chucked a load of vallisneria into my L199 tank a couple of weekends back, mainly because I'd read it can handle high flow rates - I've got three powerheads in there, after all. My leafy plants are struggling to cope, though. Then, while browsing online for something else, I came across someone on a forum who suggested vallisneria doesn't do well in soft water. Uh oh, I thought, that's exactly what I've got in my tank. I couldn't find any other sources to back this up, though - all the plant websites just say it's a pretty easy plant to grow.

Can anyone shed some light on this? I've been dosing my plants with Seachem Flourish Comprehensive once a week; that's got all the necessary minerals, right?

Val's been a breeze for me, despite having pretty soft water. I've grown it for years with no issues, actually it's been the opposite, it's done great.

That's reassuring to hear, hillsman. Given Scotland's predominantly soft water, I'm hopeful my val will thrive in its new environment.

My water's around 5.7 dGH and I've found vallisneria does alright, I think the key is it's a root feeder so it's probably more about the nutrients in the substrate or using root tabs.

dungeon wrote: ↑Tue Jan 21, 2025 3:15 pm My water's around 5.7 dGH and I've found vallisneria does alright, I think the key is it's a root feeder so it's probably more about the nutrients in the substrate or using root tabs.

Definitely need root tabs in soft water. I've found it takes a bit of time to establish, but once it does, it really picks up pace and does well.

I've never tried root tabs before, so any recommendations would be great. Do you just stick them in the substrate next to the plants, or is there a specific way to do it?

dungeon wrote: ↑Tue Jan 21, 2025 3:15 pm My water's around 5.7 dGH and I've found vallisneria does alright, I think the key is it's a root feeder so it's probably more about the nutrients in the substrate or using root tabs.

Seachem makes a great root tab that's got everything, including calcium, which vallisneria really loves. Vallis are pretty heavy root feeders, so it's worth giving them a boost.

dungeon wrote: ↑Tue Jan 21, 2025 3:15 pm My water's around 5.7 dGH and I've found vallisneria does alright, I think the key is it's a root feeder so it's probably more about the nutrients in the substrate or using root tabs.

Considering your location in the UK, I'd suggest going with TNC root plugs - they're a great option and don't need replacing as frequently as some other types I've come across.

Vallisneria generally does better in hard water, pH 7.0 or higher. That being said, some of the smaller species can still grow in soft water, as long as it's not too acidic. The one exception is Gkento4t Vallis, which really struggles in soft or acidic conditions.

I've also got soft water and I've had no issues with my vals, actually got them from my local rivers as they grow naturally here. Root tabs - they're a must, really help them thrive.