Amazon Swords - Leaf Deterioration

[ZoddyZod]

I've got a few amazon swords that seem to grow well (must be around a foot tall) but the leaves grow, deteriorate (holes appear and they eventually rot) I cut them away and they are replaced with new leaves but the cycle starts again.
 
I'd like to know what my tank is lacking that I can add or change to prevent this.
 
300L tank (around 2 foot deep)
2 x 28w 'daylight' T5s for 8hrs a day
cat litter/clay substrate capped with sand
150ml of trace elements (from 1L of 7.9g mix) dosed every Monday & Thursday
50% water change each week
Fertilizer tabs at the root of each sword
NO liquid carbon or C02 injection.
 
if the fix is carbon related - then I'll pull them out. But is it something else?

 

[TwoTankAmin]

Do you have any algae eating plecos in this tank? Do you add any substrate ferts?

 

[ZoddyZod]

I do indeed have some bristlenose in the tank. I occassionally catch them rasping on the leaves - potential cause?
 
The substrate ferts come in the form of fertilizer tablets placed directly at the roots of each plant.

 

[TwoTankAmin]

Two things thne, The bn are after algae on the sword leaves that we usually can't even see. The problem is amazon swords  have fairly flimsy thin leaves compared to most swords. The bn hole the leaf as a collateral damage from the algae rasping. The do this to compacta swords as well- a dwarf E. belheri variety
 
Next. Push the ferts unde the roos of the sword- push it in at an angle to get it down to the bottom glass while touching/damaging the roots as little as possible. For bigger swords bread tabs and push in from several different sides. You may use more than one tab doing this.

 

[SO19Firearms]

Make sure the root tabs contain Nitrate and Phosphate, even a bit of ammonium if you want to give them a real treat.
If the holes are appearing as a clearing of the leaves and you can't increase CO2 - shade them or use less light.
 
 
IMO

 

[ZoddyZod]

I'm using your tabs, S019.....so I hope they are decent
 
it's definately the BNs doing the damage. Don't know why I didn't think of this before. I tried swords a couple of years ago and they wrecked them. This time they seemed to leave them alone long enough for the plants to flourish, and have only nibbled them later on.....my memory isn't up to much.

 

[SO19Firearms]

The reviews say they are
 
If they've left them until now - I'd still wager they've grown too big for the CO2 levels in the tank - But that's just IMO.

 

[ZoddyZod]

so my plant mass may have exceeded the available C02. Take a look......what do you think?
 

 

[SO19Firearms]

I can't really see them but yeah. They look to be about half way up the tank, so plenty of light there to cause a lack maybe.
 
EDIT: Just re-read your text. It's not necessarily about mass TBH. The vallis don't really count for instance. IMO

 

[DrRob]

Any mileage in letting that vallis grow over the top a little? A little shading might solve the problem as SO19 suggested.

 

[ZoddyZod]

the vallis has grown.....it's now starting to grow DOWN the front of the tank, following the spray bar current.
 
....which means I should really trim them

 

[DrRob]

Don't trim them too far then, give the swords a chance to grow a bit in lower lighting. Might just be the lighting variation from the trimming that they're complaining about.

 

[SO19Firearms]

BIM melting leaves don't recover too

 

[ZoddyZod]

Don't trim them too far then, give the swords a chance to grow a bit in lower lighting. Might just be the lighting variation from the trimming that they're complaining about.

 
but the plant on the left hand side has never had any cover from the vallis, so I don't think it's a difference in the amount of light they get that is a cause.

 

[SO19Firearms]

but the plant on the left hand side has never had any cover from the vallis, so I don't think it's a difference in the amount of light they get that is a cause.

Was it always that size, or has it got bigger?