Help with grumpy plants

[Professor_J]

So I decided when setting up my tank that I'd actually take the plunge and use some real plants.

After some reading decided that to keep things simple I'd go with nice slow-growing tough to kill java ferns. They're ok looking epiphytes that don't need a bunch of light, nutrients or special attention (or so my reading told me) so it sounded reasonably easy as a first go and easy to undo if I needed to.

They were doing quite well for a while, but lately the plants have been losing leaves and having them turn brown and get holes in them. If I had to guess they're missing some nutrient (K?).

Water is 28-29C, pH 7.2, gH 100-110 ppm, kH 50-60 ppm, nitrate 5-10ppm, nitrite/ammonia 0.

It's a 90 gallon tank and there are right now 7 discus about 5-8 cm across I would guess, 30 tetras, 5 ottos, and 6 corydoras. They get ~35% water change 2-3 times a week and the token amount of gravel on the bottom is vacuumed once a week (I was doing it more often but even once a week I don't clean much gunk out of it).

The fish are loving life in the tank at the moment, as are my students when they come into my office, but the plants are really struggling.

Should I be adding some fertilizer to the water? If so, what should I look for, how much and how often should I add it?

[Baxter123]

They're ok looking epiphytes that don't need a bunch of light,


They might not need a lot of light but they DO need the right type of light.I use globes T8 & compact fluro's in the 6700K - 10000K range.Any light globe over or under this range does not suit freshwater plants.
I wouldn't worry about fertz as your fish will provide all the plants needs.

Cheers

[Greggy]

Too much fertilizer can also cause plants to struggle. If you'e been adding ferts perhaps do a few water changes and see if they improve after a week or two.

Remember that once a tank is fully established (around 6 months) you hardly need to add fertilizer of any kind. For example I only add a few iron tablets and 10mLs of Flourish once per month to my 6x2x2 and my plants are growing like crazy... no CO2 either!!!

My take on aquarium plants is that the more you ignore them the better they seem to grow.

Regards,

Greggy

[fish_r]

usually holes in leaves is a sign of potassium deficiency.

sorry Greggy but i disagree with what uv'e said above with the more u ignore plants the better they grow, u cant be serious can u. to grow plants "well" u need the correct balance of ferts along with lots of other factors...

[Greggy]

I'm deadly serious!

The more I've tried to 'get it right' with plants with various fancy/expensive fertilizers etc I don't seem to have much success. As soon as I forget about having plants they come good. The only thing I can think of to explain this is that the plants are getting enough fertilizer/nutrients from the various waste products in the tank, hence the extra fertilizer seems to do more harm than good.

Of course each tank is different, and some may have to add extra fertilizer on a regular basis, but for me this just isn't the case.

Agreed you need the correct balance of several important factors including lighting, nutrients, CO2 and carbonate hardness etc, but just as too little of these can hurt growth so can too much, and it is my experience that the labels on the bottles of many plant fertilizers that describe dose rates are are WAY too much/frequent compared to what plants actually need.

Right now I'm having to prune every second week due to huge growth. I can only imagine if I had a correctly set up CO2 injection system that I would be pruning weekly. I might be able to keep more exotic plants with CO2 but I'm happy with the easy ones. I guess thats the benefits of using simple to care for plants vs plants with more complex requirements. For me keeping it simple seems to be the key to success.

Regards,

Greggy

[Professor_J]

Hmm...

Sounds like it is probably potassium then - I have not been adding any ferts to the tank so they probably aren't getting "too much" of things right now.

My lights are 7000K (I just checked), so they will put out the right wavelengths for the plants.

Assuming it is potassium deficiency, how much of what should I be adding, and how often?

[tzwms]

Professor_J,
How many watts of light are you providing? Your ferns don't require a lot of light but as pointed out earlier, they need the right wave length and enough. That is why T8 and compact flors were mentioned. :)

[Professor_J]

The lights are 7000K fluorescents so the wavelengths will be right (I'm ok with physics and chemistry - the biology is where I have troubles :) ), T6 bulbs, 30W total across the tank.

The whole physics of it works out to about 55 W/m^2 of 7000K light over the tank. Sounds like plenty for "low light plants" to me.

[fish_r]

if u want to try upping ur potassium Prof u can get this from seachem http://www.aquariumsuppliesaustralia.com.au/store/cart.php?m=product_detail&p=1013
but if ur not fertilizing @ all i would start with a broad spectrum fert like seachem comprehensive
http://www.aquariumsuppliesaustralia.com.au/store/cart.php?m=product_detail&p=993
the directions in the seachem bottles are for med light tanks so i would go with what they say to dose or maybe a little less often if u dont have many plants...

if u want ur plants to grow lush and show no signs of deficiency i would advise using ferts on a regular basis but thats just my opinion...

[ILLUSN]

30w of light is too little , even for java fern, aim for 90-180w over a 90gal.
kelvin colur isn't a real good representation of spectrum. eg hagen lifeglo2 tubes 6500k and are USELESS as the spectrum contains mostly green light which the plants cant use, where as an 18000k aaquaglo is perfect as the light is produced with strong peaks at red and blue where chlorophyl is most active.

java fern survives at low light of about 1 watt/ US gal (4L). to grow it propperly you'll need 2.0-2.5w/(US)gal. your holes if they are in the old leaves are proably due to low iron or low potasium, I'd dose 1/2 teaspoon of chelated iron and a 1/4 teaspoon of potasium sulphate or potasium chloride every second night for a month.

If you get algae cut the iron, if no change up the dose to 1/2 tsp iron 1/2 tsp postasium every second night and observe for another month.

java fern grows slow at low light and low co2 so you'll need some time to see the differance.

[Greggy]

FWIW I'm running 3x 36 Watt 48" Philips Aqua Sky 6500K fluros, 3x 36 Watt 48" Philips Aquarelle 10000K fluros and 2x 8 Watt 12" generic fluros for a total of 232 Watts stagered accross the top of my 6x2x2 tank for 11 hours a day.

Western Power love me but so do my plants.

Regards,

Greggy

[tzwms]

Good post ILLUSN. Where did you get the spectrum shots?

[fish_r]

no wonder u dont have to use ferts Greggy running approx 1.3 WPG.

cheers
Rob...

[ILLUSN]

thanks tzwms, i got the spectrum off the hagen homepage.

[Professor_J]

Thanks all,

The plants are now actually coming back. Just adding food - they seem to be happy enough with the lights I've got.