Planted aquarium rejecting new plants?

[Icd1227]

So I have a 26 gallon bowfront, planted aquarium up and running probably for about a year and half now. When I first set up the tank I these plants in it:

Java Fern
Rotala Indica
Dwarf Hairgrass
Crypt Wentii
Water Wisteria
Amazon Sword

After I set up the tank the plants did well, although the water wisteria began to melt. The stems shrunk and all the leaves eventually fell off, the stems then turned brown and the plant just deteriorated. Other than that, everything else did fine.

Although, any type of plant that I try to add to the tank now that is not one of the first ones added to the tank, just completely melts and dies like the water wisteria.

The tank is running with an AquaClear 50 HOB filter, two 18 inch T5-HO lights, no CO2, I occasionally add fertilizers to the tank. I have the following fish

2 young turquoise rainbow fish
2 young angel fish
1 young siamese algae eater
2 harlequin rasboras

Do you have any idea why new plants in the tank just melt right away?

 

[Rivercats]

Without using fertilizers and CO2 or liquid carbon there most likely isn't enough nutrients in the water. I'm curious but what did the dwarf hair grass do?: It is a high light, CO2, dry ferts plant. Also it depends on the type of plants your trying to add. If your lighting isn't adequate for the plants your buying then they won't thrive.

Do you know what your nitrate and phosphate levels are?

 

[Icd1227]

I have to check my nitrate and phosphate levels but I will let you know. My nitrate levels are typically low.

The dwarf hair grass has done surprisingly well for the conditions it's in. For a long time it did not grow or spread but it did not die. In the past four or five months it has begun to spread a lot and every week or so I look at the tank and there is a new patch sprouting up somewhere.

Thanks for the tip, I know the lighting is sufficient. I'm planning on adding a CO2 system soon.

 

[Rivercats]

You need to be using root tabs for swords, crypts, bulb plants, and wisteria. Then you need to get some ferts for the water. If you add CO2 you need to start using dry ferts daily and upgrading lighting would be a good idea.

 

[Icd1227]

I have dry ferts I just don't use them daily. Do I still need root tabs with the ferts? and what kind of lighting would you suggest changing to?

 

[Rivercats]

You need root tabs for the plants I listed because they are heavy root feeders. You need to read up on dosing your dry ferts EI or PPS-Pro so plants get all the macro and micro nutrients they need on a schedule. If your lights have kept DHG going then I'd just put good bulbs like a Geisemann 6000K Midday bulb and a Geisemann Aquaflora bulb in the fixture and use the money to get a pressurized CO2 system. You can use liquid carbon in the mean time at a rate of 1ml. liquid carbon to every 2 gallons of water. But remember when you use liquid carbon and or CO2 (I actually use both together) your plants will photosynthesize and grow faster which means they will need more fertilization.