First time planted tank needs help!

[hollie13]

Hi,
So for context I have had aquariums in the past and have all been perfectly fine but never had a tank with plants in. It’s been over three years since I’ve had a tank so I may also be quite rusty.
I set my tank up over a week ago with some plants and have noticed that they don’t look very healthy anymore. They sort of look as if they are dissolving in the water and also turning brown, unsure if the pictures are showing it well.
Water test is perfect so I put some fish in yesterday. The substrate has one slow release fertiliser tablet that the shop recommended. Also all the plants I got where recommended there.
I have the fluval flex tank.

 

[Aiken Drum]

Do you know what plants you bought? Just because an aquarium store recommends them doesnt mean they are good plants for aquariums.

Are you using any plant fertiliser?

How long are your aquarium lights on for?

Plant melt is normal.

Commercially grown plants are cultivated “emersed” rather than “submerged”. This way the plants can easily get their carbon requirement from atmospheric CO2. They can be grown quicker which makes the operation much more commercially viable. You take that plant, put it in your aquarium, cut off its source of CO2 and the plant goes into survival mode. It starts to use up its stored carbon and the leafs melt. You may lose all your original growth to melt but new leafs will have a structure more suited to its new environment and get its carbon from the water. Plant melt is a normal stage in aquarium plant growth. To judge the health of a plant look for new growth rather than what might be happening to the original growth, and judge it over extended periods of time.

I would give the plants a few weeks before judging if they are doing well or not.

 

[hollie13]

I did keep the tags for each plant but I’m not back home till tomorrow.
Using a slow release tablet looking fertiliser that was recommended
Lights are on from 7am-8pm.
Thank you for replying it was very informative!

 

[Aiken Drum]

If you can let us know what the plants are. They arent immediately coming to mind. They might be high demand plants that need high powered lighting, injected CO2, nutrient dosing etc. They might not even be aquatic plants, thats not uncommon.

13 hours a day light is way, way, way too much light. What could be happening is that having the lights on too long, the plants are trying to draw on nutrients and CO2 due to the length of time the lights are on and they simply can't access enough. Result, unhealthy growth. It's all about balance. Enough nutrients, light and CO2 for healthy growth. Too much of one, not enough of another results in deficiencies. 6 to 8 hours a day of the light on will be enough for most commonly kept aquarium plants. I have very healthy plants in an aquarium with the light only on 4 hours per day.

13 hours a day will also cause a lot of algae growth which will compete with plants for nutrients.

The tablets will only be providing nutrients to the roots. Plants usually benefit from an all-in-one in one liquid fertiliser in the water. I use Seachem Flourish, but there are lots brands out there depending on your location.

What are your water parameters? You say perfect, but what's perfect for fish isn't perfect for plants. Aquarium plants generally get their nitrogen from nitrate in the water. So while you want nitrate as low as you can reasonably get it for fish, you want it high for plants. 10 to 20ppm of nitrate is usually a good compromise between the needs of the fish and plants.

Flex tanks don't give much scope for substrate because the bottom intake grill is so low down. You can only really get an inch of substrate in them. They aren't ideal for rooted plants because the substrate isn't going to be deep enough. I would personally recommend rhyzome plants rather than rooted plants. I do have some cabomba in a flex but it isn't rooted very well.