Browning Plants - With Photos

Hi all
 
I'm generally happy with my aquarium and it looks great overall. The plants grow (some rapidly) and the there is a lot of healthy green.  understand they are all suitable for low tech set ups. However, I have noticed in the last couple of weeks some discolouration on leaves and wondered if there was a simple fix, without upgrading lights or investing in CO2 injection.
 
I've attached some photos below.
 
1) Bacopa - this has only been in the tank about 3 weeks and is showing some signs of browning. Its growing slowly
 
2) Nymphoides SP Taiwan - I've had this about six months and it grows really quickly. Some of the leaves go paper thin or transparent around the edges and I usually just remove them. Lately it is also showing a little browning on some leaves.
 
3) Crypt (unknown type) - I've had these about a year and they have been very bronze/olive for most of that time, although they were greener when I bought them. My growth on these is slow, although constant. Just lately they are looking a little greener than they have been.
 
Some stats
 

• tank size: 250 litre tank
• lighting :3 x 39W T5 (iquatics bulbs comprising one marine white and two tropical)
• photo period: 6 hours on timer per evening - tank is also near a window and gets indirect (UK) sunlight through day
• bioload: approx. 40 fish, 20 of which are cardinals and rummy nose
• chemistry: weekly reading of nitrate is approx 20ppm. no nitrite or ammonia. I know my water is soft, but not sure of reading. PH is a middle 7
• Fertilization: I use Tetra Crypto tabs occasionally and Easy Life Pro Fito liquid fertizer occasionally.

 
Just recently I've started to experiment with Flourish Excel. Initially I added this every couple of days and dosed the Easy Life fert weekly to support the uptake. Then I noticed unusually high Nitrate and established through some browsing that the Flourish Excel may have been the cause. So I did two 50% water changes and Nitrate is stabalized again around 10-20ppm. This week I just added a single dose of Flourish Excel the day after water change.
 
At the same time, I have been experimenting with the lights. I changed to the iquatics bulbs about 2 months ago. I instantly noticed they seemed really bright and was concerned that I might get an algae breakout. So when I wasn't home, I just had one of the bulbs on timer, then switched all three on only when I was home. In the last two weeks I've reverted to having all three on the timer again.
 
I'm not experiencing a plant disaster, but I feel they could look better. Any help appreciated. Although as said above, I don't really want to upgrade lights or add CO2. Maybe I just need to stop messing with Flourish and the liquid fert? or maybe I have the wrong plants for my setup?
 

dazbud said:

I don't really want to upgrade lights or add CO2.

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You've got that the wrong way round - you either add CO2 or down grade your lighting.
Higher lighting makes for greater CO2 uptake in the tank - so if you're lights are too bright you must add CO2 or reduce them.

With that in mind you're also making a lot of changes all at once so too difficult to pin anything down.
Excel/Liquid Carbons needs dosing everyday - and when you do that you'll need to dose a Complete fert containing Nitrates and Phosphate (preferaby also daily)....IMO

And don't worry about your Nitrate.

At very least you need to dose liquid carbon every other day (everyday much better option) Crypto tabs will last about 2 perhaps 3 months max before they needing replacing, the minimum liquid fertiliser application should be once a week preferably after a water change, you may need to add some phosphate too keeping it simply to a 10:1 ratio IE to your 20ppm Nitrate (which is a good level to maintain for a planted tank) your phosphates should be at 2ppm

Thanks guys . I thought the easy life fertiliser would include phosphate but maybe it doesn't. Might increase the flourish excel to a regular dose, with all three bulbs on their set pattern and see what happens. The nitrates did rise to about 40ppm when I dosed excel before and this was what made me panic

Depends which EasyLife fert. If Profito, this contains no nitrate or phosphate.
Excel should not increase nitrates. If anything it should encourage plant uptake of nitrates. Where did you find evidence that Excel causes high nitrate?

dazbud said:

The nitrates did rise to about 40ppm when I dosed excel before and this was what made me panic

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Added inorganic Nitrate is nothing to be afraid of - especially if you're relying on a test kit to give you the figure.
If the EL is Profito it's just trace. Fosfo, Nitro and Kalium provide Phosphate, Nitrate and Potassium.

HTH

The evidence of the Nitrate peak following Excel was observed in my own tank. As this seemed to be the only thing that had changed I looked it up and found a couple of similar blogs on here and other sites. I know it seems odd as Excel is expected to encourage plants to take up nutrients. However, I read that in doing so, they will compete against the algae and the algae will starve and die. The dead algae causes the nitrate to rise. Unsure if this is correct or not, but I did get a reading of 40ppm while using it, which is double what I normally see.
 
Yes, just realised that Profito has no phosphate. Think I avoided phosphate when shopping for ferts ages ago as I read that this also can cause algae. I guess now though with stronger lighting and Excel that a little phosphate might be effective. Is there a liquid fert that includes phosphate and would compliment my low tech setup given that the nitrates seem to be a stable 20ppm?