Too much light?

[Phaewryn]

I brought my floating plants inside into a 20 gallon aquarium filled about halfway and hung a 14w LED grow light (https://www.walmart.com/ip/Great-Va...th-Integrated-Outlet-up-to-10-Units/852904069) over it. It's been a couple of months now and I've had to compost a ton of salvinia because it tries to take over, so it's working well, but I've notice that the frogbit that is directly under the light tends to turn pretty yellow and look unhappy whereas the pieces that have floated more towards the edge that are not directly under the light are looking greener and happier. Is the frogbit just getting too much light?

The light is about 4" above the water surface.

Are there just too many plants and not enough nutrients?

I don't have any fertilizer or fish food to add to it. I've tried tossing in a few pieces of cat food to try to "feed" the plants but I don't think it does anything and I can't afford to buy anything either.

Should I take some of the frogbit out so there's less competition for the nutrients? Or should I try to move the light to one side so there's more area out from under it?

 

[Phaewryn]

Edit: there are tons of little snails. No fish.

 

[JRS]

The brighter the light, the more nutrients and trace elements a plant is going to need. Not experienced personally with the requirements for those plants. If those plants can live outside in the sun, even partial, it is way more than that light you have. If that is the case, likely the nutrients are the issue as you suspect. Lowering the light level can help also, raising the light or offsetting as you mentioned can help.

Even in my low light tanks, I have to add fertilizer eventually as stuff starts to yellow. For my Bacopa, I occasionally drain some old water from another tank during water changes into the tank. A bit of terrestrial fertilizer can help also if you have that, Osmocote or MiracleGro.

Some of my plants, water lettuce and Bacopa did poorly during the winter due to the dry air. Covering the tank with a glass or plastic top would help if that is the case.

 

[Phaewryn]

The brighter the light, the more nutrients and trace elements a plant is going to need. Not experienced personally with the requirements for those plants. If those plants can live outside in the sun, even partial, it is way more than that light you have. If that is the case, likely the nutrients are the issue as you suspect. Lowering the light level can help also, raising the light or offsetting as you mentioned can help.

Even in my low light tanks, I have to add fertilizer eventually as stuff starts to yellow. For my Bacopa, I occasionally drain some old water from another tank during water changes into the tank. A bit of terrestrial fertilizer can help also if you have that, Osmocote or MiracleGro.

Some of my plants, water lettuce and Bacopa did poorly during the winter due to the dry air. Covering the tank with a glass or plastic top would help if that is the case.

My pond is mostly shade (it gets maybe 3 hours of mostly filtered sun in mid-summer, and basically no sun by the end of September), so I'll try offsetting the light. I didn't think the cheapest light at Walmart would be this effective.

I wonder if I'm giving it too many hours of light? I turn the light on as soon as I get up at around 9:00 to 9:30 in the morning and I don't turn it off until I go to bed around 11:00 at night.

I did try some garden fertilizer and it didn't seem to make any difference, perhaps because it was 20 years old and dried up.

My partner has newer holly and orchid specific food at his house, I'll try one of those.

 

[GBBUDD]

The brighter the light, the more nutrients and trace elements a plant is going to need. Not experienced personally with the requirements for those plants. If those plants can live outside in the sun, even partial, it is way more than that light you have. If that is the case, likely the nutrients are the issue as you suspect. Lowering the light level can help also, raising the light or offsetting as you mentioned can help.

Even in my low light tanks, I have to add fertilizer eventually as stuff starts to yellow. For my Bacopa, I occasionally drain some old water from another tank during water changes into the tank. A bit of terrestrial fertilizer can help also if you have that, Osmocote or MiracleGro.

Some of my plants, water lettuce and Bacopa did poorly during the winter due to the dry air. Covering the tank with a glass or plastic top would help if that is the case.

Frog bit in my experience does not like to be disturbed and can take some time to get established once it finds a happy home.

 

[Phaewryn]

I suppose I could buy a cheap feeder fish next time I'm in the city, just for its waste generation. In 10 gallons, will 1 feeder goldfish make enough waste to feed the plants?